I am frankly quite disappointed with the overall experience... coupled with the digital rebel xt, this $650 lens wont give you any more sharpness than the 50mm f/1.8 which runs at about $70. Further, at 17mm (27.2mm equivalent on the xt) the wide angle distortion is very visible...Also between 35-40mm, the lens' transmitted contrast degrades very fast (look at the MTF charts on canon's website). Further, in low light conditions, the f/4 isn't very helpful...The UV filter runs at about $40. This $700 experience isn't very pleasing. You don't get what you pay for at all.

I initally had my doubts about this lens over the 16-35 2.8L, but decided to give this one a try since it is roughly half the price. I am shooting film, so I have the benefit of the full 17mm at the wide end, and this lens truly does not disappoint. It is crisp, colors are bright and accurate and the coverage is excellent. The focal length gives enough flexiblity to be able to compose almost any wide angle shot you could thing of.

While the 16-35 does give you the extra f-stop, really consider if it is worth twice the price for what you are shooting. If you are like me and shooting mostly still lifes and landscapes, it probably isn't.

This is a very good zoom lens. It's definitely a Canon "L" quality. I have a Canon 300D SLR and purchased this 17-40mm plus a 50mm f/1.4 lens to cover most of my photography needs. It is also ligheter than the 24-70mm f/2.8L. However, if I could do it again, I would have gotten a 24-70 f/2.8L which is a much clearer lens and covers the whole range that I wanted.

I TRIED THEM ALL FOR MY 350 XT REBEL,THE TAMRON 18-200 AND THE TAMRON 28- 75, THE CANON EF-S 17-85, THIS LENS 17-40mm f/4L IS EASILY THE BEST IN QUALITY OF PICTURES AND EVERYTHING ELSE
TOOK ME 3 MONTHS OF TRYING DIFFERENT LENS THIS IS MY FIRST L LENS AND I'M SOLD. PROBABLY WILL GET THE EF 70-200mm f/4.0 L
THIS LENS IS LIGHTER THAN THE OTHERS TOO ALSO IF YOU HAVE A FILM CAMERA YOU HAVE ONE OF THE BEST WIDE ANGLES OUT THERE! CANT DO THAT WITH YOUR EFS LENS & TAMRON 18-200 AS THEY ARE FOR DIGITAL ONLY. COMES WITH LENS HOOD A BIT UGLY, AND NICE LENS POUCH.

As a photographer, I have not yet succumbed to the pleasures of having one all-around lens for landscape, people and street photography (I personally prefer single focal length prime lenses since these tend to be sharper, contrastier, and relatively more free from distortion, than zoom lenses, though zoom lens quality is now quite close to those from primes.). However, if I was interested in acquiring one lens which would allow me to photograph easily landscape, people and street scences with the flexibility of focal lengths from an ultrawide angle to nearly normal perspective, then this lens would be a superb candidate. The test reports I have read in several photography magazines, most notably in Shutterbug, and I believe, Popular Photography, too, have been absolutely enthusiatic in their praise for this lens. Not only is it among the cheaper lenses in Canon's superb L Series line, but it is apparently among the best. I have also met photographers who are truly quite enthusiastic about this lens's capabilities. So if you are a Canon owner seeking a superb-quality wide angle zoom lens of this range, then you shouldn't hesitate buying it soon.

I traded in my EF-S 10-22 for this one, realizing how often I switched back and forth between 10-22 and 24-70. I took some stats in fact, and it turns out I stay mostly between 17-35 range, and never really go any wider than 15-16 even with the 10-22. The wider range of 10-22 certainly gives you a lot of freedom, but I found it to be a bit too artificial due to the unavoidable barrel distortion.

Now, 10-22 is certainly a solidly built piece of glass, but 17-40 does deserve its L label and the red ring. It feels a little heavier than the 10-22, and the focus ring turns with sufficient weight (10-22 feels a little on the lighter side) you can actually fine-tune the focus with greater accuracy. Being an L-series lens, it comes conveniently with a lens pouch and hood.

Under darker conditions, the focus seems a little slower than my other faster lens, but even at f4, it takes crisp shots. I highly recommend this for anyone with a Canon dSLR. If you're planning on moving on to the 1:1 crop bodies (1d or 5d, a less expensive sibling coming out in October) 17-40 can be a good piece of glass to have, as you're going to have to let to of the 10-22 anyways.

I did have a chance to try the 16-35L, but at the smaller aperture range, the difference seems nominal, especially considering the price difference.

I use Canon EOS 20d and Elan 7, and they both pair up nicely with 17-40 4L.

I actually returned this lens because it casts a large shadow when used with the built in flash - going to wait till I can buy an eos with a 1:1 ratio so i dont have to get the low mm lenses to get a full frame

I've been using this lens for 2 years, always attached to an EOS 10D.

Good build quality, good optical performance. It becomes somewhat short if used as a "all purpouse lens" (even with the 1.6x 10D crop factor).

with the 1.6X zoom on my rebel xt, this lense is still wide. the pictures are razor sharp, saturation is perfect, nice and compact, canon "L" quality definitely shines here. if you want one of the best lenses for your canon, look no further. the only downside to this lense is that once you go "L" - there is no turning back.

My school owns this lens, and after using it, I realized that I had to have a copy of my own.

I recently purchased a 1d Mark II N and I also got the 17-40 L to go along with it. (Take Into Account The 1d2n has a 1.3x Crop factor, not 1.6x like the 10d, 20d, 300d, etc)

To start off, I've had my share of lenses and this lens stands up among the rest as being one the best. Solid, fluid USM with the ability to manual focus while in autofocus. (full time manual focusing)
(...)

Pros: Size (it's solid, but light compared to the sigma 24-70 2.8), USM, comes w/ lens hood and lens pouch, sharpness, color, contrast, sharp even wide open at f/4, very wide on the 1.3 crop body (as wide as my old 15mm fisheye on my old 1.6 crop body)

Cons: Little pricey, f/4 can be a little tedious in low light

Overall: This is an excellent lens. I love its size and I can feel confident shooting with it wide open.

(...)

This is my first L lens, and I like it very much. This is an ultra wide angle zoom lens which give you a much broader angle of view. I wasn't happy with the kit lens and the 28-135mm IS I had before in the term of wide angle. I later brought 70-200mm f/4 L lens which is on of the great lens that Canon offers for the price.

A friend photographer for a local newspaper showed up with one of these, brand new! I tested it against the 28-40 range and the pictures were completely identical in every way, sharpness in every corner, contrast, etc.

Just thought I let you know.

I have had this lens for almost a year now. I bought this with a 350 XT body only. For a long time this was my only lens and pretty much this is all I needed.

I have used it extensively, the contrast and sharpness are great, it is relatively fast and extremely reliable, the success rate with this lens is excellent. The outdoor scenic shots are breathtaking. For the money this is the best wide angle lens you can buy.

Compared to the 2.8 's it is way less expensive and easy to carry. The 2.8 to 4.0 gap can easily be covered by changing settings on the XT in most cases.

Also it gives a nice grip when held from the lens and this results in steady shots at high ISO settings. I have used it for nightshots, the shutter speed has to be slow to get the shot, got good and sharp results with the lens.

I have added a 50mm 1.4 prime lens to my collection but the 17-40mm is the one I have on most of the time when going out.

Like every Canon "L" lens, this one gets endless great reviews from amateur and semi-pro photographers on the Internet. Trouble is that it's actually not very sharp. It's well-built and consistent in its performance, but the high-contrast edges are just not there at any aperture.

People give this lens high marks in comparison with consumer zoom lenses, but in comparison with most professionally well-regarded zooms, this lens is a waste. If you want something like this in your EOS system, splurge on the 16-35mm f/2.8L, or buy prime (non-zoom) lenses to cover the range.

For the money I don't think there is a better lens. It is very sharp and focuses very fast. It is weather sealed and has a rubber gasket that seals the lens mount on the camera. It is a bit slow at f/4, but given the cost of the 16-35 f/2.8 lens I can deal with it.

I just bought this lens and am totally in love with it. The wide-angle is beautiful, captures great area without distortion around the edges which is exactly what I was looking for. Fast and light, the performance has been excellent. This is my first L lens and I am totally hooked, will definitely invest in L's in the future. The only thing negative I can say at all is that when you have the hood attached, and use the built-in flash, it casts a small shadow. I usually use a mounted flash anyway so it doesn't affect my shots, but if you only use the built-in flash, be aware of this.

If, like me, you are a fan of wide angle shots with their greater sense of depth, and encompassing vision, then you will love this lens.

The 1.6X multiplier of my Rebel XT takes away the extreme wide angle capability of this lens, but nevertheless the range is impressive at an effective 27 to 64mm. This makes the lens a very effective general purpose lens, ranging from a great wide angle to slight telephoto. I normally leave this lens on my camera, only swapping it for a telephoto zoom for outdoor/sports shots.

The quality is just great - the pictures jump out at you for their color, contrast and sharpness. Even though this lens costs almost as much as the camera body, there is no question that it is worth every penny. If you are thinking of buying the new 30D with a lesser lens, then you might want to consider saving the money on the body and splurging on this lens instead.

You won't regret it!

This lens is the best purchase that I've made yet for my Canon Rebel XT. Amazing color, contrast, and sharp. It's my everyday lens and money will spent.

I have both 16-35 and this 17-40. I end up using 17-40 lot more than 16-35. No doubt, 16-35 is a better lens, faster, wider, but this only helps in one condition: indoor shots where flash and tripod is prohibited. I bump into this situation when I was in the Hearst Castle and 16-36 helped a lot. Another situation is indoor-event without flash, but not too often you'll bump into this situation. Maybe funeral service inside the church?

Again, these situations are rare. Usually I use the wide angle lens for landscape shots or group photos. For landscape, I'm not going to use f/2.8 anyway. For group photos, it's another no-no.

Therefore, 17-40 is a more reasonable choice. Again, it's F/4, but you don't have too many chances to use f/2.8 anyway. It's half the cost and it's lighter.

Many first-time users of DSLR face the situation of buying a wide angle lens. I highly recommend 17-40. It's one of the cheapest L lens but you'll end up with much better pictures. The results are instant. Of course, if you have enough cash, buy 16-35, but you'll find yourself reducing aperture most of the time, which, isn't that what 17-40 can do?

Canon's L lenses are generally expensive, for good reason. Along with the 70-200 F/4 L, this lens is probably the best overall value in L glass.

Build quality leaps out even when you hold the lens in your hand, size /weight/ balance is perfect (for me), optics are excellent, focal length (17-40mm) is extremely useful for digital shooters (with a 1.6 crop factor SLR such as the Canon 20D).

My only complaint is that it is often not fast enough for indoor/available light shooting (without a flash, which I do not like to use if at all possible). On the other hand, the 16-35mm F/2.8 is twice the price and not noticeably better (at F4 and over)

I have compared it to Canon's non-L primes such as the - 20mm, 28m etc. It compares well in terms of clarity, sharpness, color
rendition.... and it is cheaper than buying all these primes and a lot easier to carry, besides being much more versatile in a real life shooting situation.

For this range of focal length, it is a GREAT CHOICE!

I love buying the best value lenses from Canon like the blazingly fast 50mm 1.8 or the razor sharp 85mm 1.8. The 17-40 L is no exception; in fact it's the best value lens from Canon in my opinion, how so? Consider the following features.


RANGE: I use this lens on the Rebel XT. With a 1.6 crop factor this lens will provide an angel of view of 27-64. That's a great range for taking pictures in the forest preserve for example. It would have been nice if the lens was a little longer (more like 80mm on 1.6 a body), but with 8MP and Photoshop crop function does it really matter? Not really, I always crop to create beautiful animal pictures in post processing and still maintain excellent picture quality for prints up to 8-10 inches.

SIZE & CONSTRUCTION: Yes I list this second because this lens blows away all other canon lenses that I own in construction quality. Its solid as a tank and it balances the XT so well that I can hand hold it with confidence and comfort. Although it weight 1.1 pounds the lens never felt too heavy, just right.

SHARPNESS: very sharp at all apertures, but best by 8.0. I am close to affirming that this lens will produce sharpness at par with many primes at that aperture. That's very impressive if you consider that is still a zoom even if it's an L.

CONVENIANCE: Coming from using mostly primes its so much fun to use a zoom like this one. Now I pretty much own 4 lenses in one. Yes think of it as owning the 20mm + 24mm + 28mm + 35mm none L primes for half the price combined. The only draw back is that this lens is 1-2 stops slower than those lenses. Otherwise it's almost or as sharp and more convenient to use.

VALUE: At the $600 range this lens offers an unbelievable value plus the $50 rebate from Canon and the Amazon 3% credit card rebate I was able to get this lens for what it sells for used on line, which means the lens holds its value very well. That's some great value, thank you Amazon!


There are many great value lenses, but each comes with a weakness. For example, the 50mm is very cheap in construction and the 85mm is soft on the wide end. The 17-40 L on the other hand is just amazing! It did not disappoint me in anyway except possibly its limited reach on the upper end (40mm only). Otherwise I see no weakness in this lens. Some people may consider the 4.0 maximum aperture too low, but it served my landscape and nature needs incredibly well. If you need an extra stop for portrait get the 16-35 2.8. Otherwise this is the lens!

PS. if you are shopping for few Canon lenses check out my other reviews. I have all the lenses that I own or was planning to buy reviewed on Amazon. Good luck with your search!

No one lens accomplishes every photographic objective. Canon makes each lens at every price point well-suited to various tasks, but with limitations that can only be overcome by graduating to the next higher priced but similar item. A case in point: the wide-angle zooms.

The 17-40mm f/4 is one of Canon's best deals in L-series glass. You have to spend twice as much to get a lens of similar quality, but just one stop faster. Does this make the more-expensive EF 16-35 f/2.8L a ripoff? Not for its own specific use: the extra stop gives you the speed to shoot in more indoor situations. Not all photographers need this. When indoors, we're often taking pictures of people, which are better suited to lengths around 50-100mm. To capture sweeping panoramas of parlors for Architectural Digest (or Coldwell Banker) the f/2.8 is the better lens and worth the step up in price, though in many cases you could use the f/4 lens with a tripod. All this means is that the f/2.8 is priced for professional specialists whereas the f/4 is for more general use. My bigger point is that Canon has its whole lineup positioned: the differences across lenses are specific and appropriately priced, which is good news for the consumer. It's hard to make a mistake buying homegrown Canon lenses, especially L-series lenses. You just have to figure out which set of two or three suits your range of uses.

The 17-40mm is a steal for people who need a walkaround lens for travel and outdoor photography. The shorter focal lengths of the zoom are great on a digital body, with nice reach and minimal distortion; just an ability to grab up landscape and wide situations end-to-end, even when standing close. The focal lengths around 40mm are tight enough for portraits and other local detail. Colors are strong and convincing; contrast deep and impactful. The lens itself is small enough and light enough to grab-and-go, but nicely machined, with solid fit and finish. It has an instantly recognizable profile, with the added bonus of the red ring.

This lens, plus a 70-200mm f/2.8 telescope and a nice fast fixed lens in the range betwixt are all you need. On vacation, and in most outdoor situations, the 17-40mm alone suffices. It makes a good first L-lens, and a staple in the arsenal.

This lens is really not meant for Canon Digital SLRs. The multiplying factor negates its wide angle capabilities.

I bought this as a wideangle lense for my Canon 20D and its just as great as everyone told me it would be.
this was well worth the money.

This is a magnificent lens deserving of high praise. In general, I tend to shoot "available light" and towards wide angle, and EF 17-40 F4L is one perfect lens for someone like me. On an APS size sensor camera (mine is Rebel XT), it works approximately like a 28-70 mm zoom--a perfect walk-around lens, giving you decent wide angle and at the tele end, a pleasing perspective on faces you expect from a moderate telephoto. I spent two weeks with EF 17-40 on the coast shooting nature and street stuff in small towns. It performed perfectly. But I only realized what a real treasure I have when I began having second thoughts about it on the eve of a long overseas journey. I asked myself whether I would not have done better buying EF-S 17-85 F4-5.6 IS. After all, it gives you better reach - an equivalent of 28-135 mm zoom on a 35 mm camera. Would it not be a perfect lens on an overseas trip? A dilemma worhty of Hamlet. So I decided to order it from Amazon while I still had time to return EF 17-40. As soon as EF-S 17-85 came, I did some tests taking pictures of still life, flowers and a portrait at similar focal lengths and at full zoom. The results put 17-85 to shame. Color and light were flat and paled next to 17-40. But there was still the problem of reach. I took a portrait at full zoom of the same person (40 mm or 65 mm equivalent and 85 mm or 135 equivalent), cut out the critical focus area from both pix and equalized the two crops in terms of pixel numbers. Unprocessed, 17-85 produced a perfectly focused picture, the 17-40 crop was visibly softer, but in terms of tonality and richness of gradations, it was way ahead of its rival. Photoshop to the rescue! After I fiddled with sharpening and contrast in CS2, the focus softness in 17-40 was gone, and the result was a better all-around picture of the same portrait detail. In other words, if you wish to take a picture, say, of a building's detail or a monkey mug shot in a zoo--a situation calling for a telephoto of 135 mm that 17-85 is capable of--EF 17-40 F4 can do the job, in fact a better job in terms of textures and tonality--and focus, too, if you do a little post-processing in SC2. I am returning EF-S 17-85 and will stick with EF 17-40, taking it on my overseas trip. Unlike EF-S 17-85 F4-5.6, which is a feels like a decent consumer zoom, EF 17-40 F4L is built like a tank and has weather sealing. It should also come in handy if and when I decide to switch to a full-frame camera (EF-S lenses work only with the APS-size sensors).

Having owned the distortion-prone Nikkor AFS 17-35 f2.8D for six years, it was time to switch over to Canon's EF 17-40 mm f4L USM. Canon's version was over a $1000 cheaper, optically superior and lighter in weight. For me, an outstanding standard lens when coupled with the Canon 5D.

Vignetting at f4 is minimal. Adobe Photoshop CS2's vignetting tool can correct the vignetting.

Distortion at 17mm is minimal. Less than Canon's EF 16-35 mm f2.8L USM set at 16 mm.

With the 5D pointed at a blue sky, the EF 17-40 hunted for a focus point while the EF 16-35 didn't.

Flaring is minimal when compared to the EF 16-35.

Portraits taken at 40 mm produced better results than the EF 16-35 and AFS 17-35 at 35 mm.

Images produced at f4 are sharp. At f8, the images are very sharp.

This lens is a definite keeper.

Don't listen to the reviews that claim that this lens is not a good choice for cropped sensor cameras (IE the 20D, 30D, Rebels etc) the Canon L lens are the best and this particular lens is no exception. I have had the lens for less than 24 hours now and am in love with the sharpness and color already.

Great lens, great color, so well built, super sharp, just watch out if this is your first L lens, you'll be hooked.

This is a lens you will have for many years, great investment.

I am really glad that I bought this lens. It comes with hood which can be reversed when not in use so it is very useful. Leather pouch, front cap, and back cap is included. Focusing is super fast with USM.

This lens produces magical images. I am stunned by its sharpness, contrast and color saturation. Simply amazing! This is a great option as a standard zoom for APS-C cameras and a great wide-angle option for full-frame.

For APS-C ussers, I have sold my EF-S 17-85 IS USM because this is just miles better. I simply love this lens! I am now so sold on the difference an L makes, that I have also sold my telephoto lens for a 70-200 f4 L.

I believe this is a great investment because:
* Canon lenses lose very little of their value
* Should Canon abandon the APS-C sized sensor for full-frame 35mm, then the EF lens range will make your kit far more future-proof
* Once the initial sting of the price has receded, you will never regret the quality of the images you take with this lens

Just try it - it's awesome!

This is a great lens. I use it on full-frame film and digital SLRs, and love getting ultrawide shots. However, if you have the cash, you'll probably be happier with the 16-35/2.8 lens, as f4 can be pretty slow indoors.

The walkaround lens. This very topic leads to a heated discussion among DSLR photographers.

First, determine your budget, focal length, and aperture needs.

If you frequently find yourself zooming out to get everything in a frame, you will want a wide angle lens such as this. If you frequently find yourself zooming in, this is not the lens for you. On a full frame body such as Canon EOS 5D, this lens becomes ULTRA wide angle (0.5x to 1.1x zoom range). On an APS-C crop body such as Digital Rebel XTi (which I used for this review), it becomes MEDIUM wide angle. But thanks to 1.6x crop factor, this lens expands to more usable zoom range of 0.8x to 1.8x.

Second, audition the lens if you can.

By definition, a walkaround lens should be relatively portable. At 1.1 lbs., Canon's EF 17-40mm f/4L USM is neither super light nor neck breakingly heavy. In fact, it weighs almost the same as Digital Rebel XTi -- really nice balance. The lens feels very solid with supreme build quality that only L-series lenses offer. Although this lens is weather proof and therefore sealed against liquid and dust, I strongly recommend getting a 77mm filter to protect the front lens element. With it, this lens is made to last. In terms of looks and feel, it doesn't get much better. Its full-time manual ring USM focuses smoothly, quietly, and quickly.

You may tolerate heavier lens or may not mind lesser build quality of cheaper lenses. A walkaround lens will be used very often, so make sure you will be comfortable with it.

This lens is famous for saturated color and deep contrast. Its images are simply stunning. At 17mm wide angle, barrel distortion is noticeable but relatively mild. From 24mm to 40mm, its images are distortion free and perfectly suited at capturing people.

Vignetting (corner darkness) is minimal with mild chroma abberrations (color shadows). At f/4 aperture, details become noticeably softer toward the edges. The center region is very sharp and at f/5.6, edges remain fairy sharp. Thanks to 7 diaphragm blades, this lens can produce very nice bokeh (blur effects).

One of the most cited weaknesses is the f/4 aperture. In my experience, a bump in the ISO speed (200 to 400) and steady hands are all you need to take well focused images indoor. On the other hand, if you are shooting with very low amount of light (evening with very low ambient light), you might wish for f/2.8. Although the difference between f/4 and f/2.8 is just 1 stop, my other lens, Canon EF 24-70mm f/2.8L USM (too heavy to be my walkaround lens) easily outperforms in such challenging situations. It's also worth noting that Digital Rebel XTi implements auto focus system optimized for f/2.8 or faster lenses. But by and large, I was not handicapped by the f/4 aperture.

Some of the main competitions (sorted by price):
- Sigma 18-50mm f/2.8 EX DC: Arguably the best wide angle lens for limited budget. The focus mechanism is a bit slow, corner is very soft, chroma abberrations can be a bit of an issue, and the lens is highly prone to flare. Works only with EF-S mount.
- Sigma AF 17-70mm f/2.8-4.5 DC macro: A bit more expensive than Sigma 18-50mm, but has wider focal range with macro capability.
- Canon EF-S 17-85mm f/4-5.6 IS USM: This "traveler's lens" has a wider focal range than most wide angle lenses (widest among Canon) and is equipped with an image stabilizer. But the lens is famous for extreme barrel distortion at 17mm and chroma abberrations. Works only with EF-S mount.
- Tamron SP AF 17-50mm f/2.8 Di II LD Aspherical (IF): This is the most direct competitor. It takes sharper images with faster aperture while costing less. Both the build and focus mechanism are significantly worse, but should be good enough for many. Works only with EF-S mount.
- Canon EF-S 17-55mm f/2.8 IS USM: This is THE reference, if you can afford it. Its images have razor sharp details and great performance all around (minus vignetting, which is typical of EF-S lenses). The build quality is worse than L-series but not too shabby. Works only with EF-S mount. This is the best EF-S lens hands down.
- Canon EF 16-35mm f/2.8L USM: One of the most expensive wide angle zoom lenses. It's larger and heavier, but has f/2.8 aperture.

This is how Canon EF 17-40mm f/4 USM stacks up.

Pros:
- Among the very best build quality.
- Excellent, buttery smooth, super fast front-focus system.
- Top notch color and contrast. Very sharp center resolution.
- Almost non-existent vignetting, generally low distortion, and well controlled chroma abberrations.
- Ideal weight and size for walkaround purpose

Cons:
- Edge softness at f/4 aperture.
- Narrower focal length than most competing lenses.
- Slower than some third party lenses.

All in all, this is an excellent wide angle walkaround lens. It may not offer the most bang for the buck, but if you value full frame compatibility (EF lens mount) and excellent build quality, this is the default choice. This lens comes with a nice pouch and a lens hood. I find the hood to be somewhat ridiculously large and because the lens is resistant to flare, I do not use it often when shooting outdoor.

(I really want to give this lens 3.5 stars)

This review is written from the viewpoint of someone whom has used many L-class lenses, and as such will be a little harder on this piece of glass. If you've never used a Canon L lens and you purchase this one, I guarantee you'll be quite pleased with your purchase. But this review is really meant for those who own other L glass pieces and are looking into adding this one to their collection.

The good:
L glass tends to mean some heavy-weight glass, however this lens is surprisingly light and small. In fact, it is the smallest/lightest L zoom Canon makes. You find yourself more likely to take it to places where there may not be much of a projected photo opportunity or where there is a higher risk in damaged gear due to its unobtrusive size. It really is one of those few L lenses that you can casually walk around with and not garner much for attention.

As with all L-glass, this ones very solidly constructed. It has a simplicity of design that minimizes risk to moving parts from shock. It is well-balanced and just feels like a tight glass package.

The lens performs very well in color and contrast. Natural saturation is excellent, easily on par with the L expectation. The color and saturation of this lens sits somewhere between the 70-200mm f/2.8 IS and the 24-70mm f/2.8.

I initially thought that the zoom range would be constraining (a mere 23mm of range?), but in reality the lens is fairly versatile. This especially true on a 1.6 FOVCF body (20D, 30D, 350D, 400D, etc), where the range is more like that of a normal zoom, at the cost of the super-wide advantage. The lens handles pretty much all composition tasks except those of a telephoto or 1.0x macro. You won't be disappointed in the zoom versatility.

Price. This like, what, the second cheapest L lens available. For those whom are very accustomed to purchasing/collecting L lenses, anything under a thousand dollars really is considered on the cheap side. If this is your first L purchase, this lens or the 70-200mm F/4L are your places to start.

Flare. There's practically none.

Cons: (there's only one, but its a biggie)
Sharpness. This is by far my biggest qualm, and what makes me frown a little at this lens for its L designation. It's nowhere near that of other lenses. One of the biggest uses for this lens is landscape photography, where objects appear very distant and sharpness becomes crucial. 24mm at f/4 on this lens is easily less sharp than 24mm at f/2.8 (!) on the 24-70 f/2.8L. And as a little investigation will reveal, this probelm is also somewhat appearant on the 16-35mm f/2.8L (although it seems less pronounced). 100% crop comparisons of this lens to other lenses such as the 180mm f/3.5L is simply a joke.

Other:
This lens utilizes slight movement of the front element, so it is advised by pretty much everyone that a UV filter be purchased (77mm filter size). I add to that by saying: buy only the Multi-coated from B+W or Hoya if you're shooting digital. Yes, they're usually somewhere around eighty bucks, but spending forty on something that will bring you ghosting/contrast woes is not worth it.

The hood of this lens is hilarious. It's almost five inches wide and maybe an inch and a half tall. I simply don't use it (I can't geometrically see how it helps. I think it may be something of a feel-good-hood if you're not consiencious about flare.) The lens is less conspicuous without it and I really don't have a flare problem.

Conclusion
I'm really not satisfied with the sharpness issue. It seems at least somewhat appearant on almost all Canon's lenses below 35mm. (Except for the 24-70 and 24-105, which is odd). I think they're still working out their wide-angle formula. Appearantly, the new 17-55mm f/2.8 is supposed to be sharper than both the 17-40 and 16-35, so they are probably on the right track of improving the issue.

In the end, if you've never used L glass and are considering this one, buy it. You will be very pleased, I assure you. But if you own a good deal of L glass, you may want to hold off from this one and wait for Canon to improve their optics. You may find yourself like me, using other L pieces and only using this one when I absolutely have to.

This is my first L lens. As an amateur, this really makes you see the difference in lenses. I use this as a general lens and have basically put away the lens that came in the kit. I am also planning to purchase the 100-400mm IS for better wildlife and family sports photography. Wish it came with a better lens hood.

"Wow!" is all I can say to express my reaction after getting prints taken with my 17-40. I've been using Nikon manual-focus Nikkors since 1988 and was always satisfied with the color and sharpness. However, after using the Canon "L" series, I've sold a lot of my Nikkors. The color, clarity, sharpness, and detail of the "L" lenses are amazing. The prints have this 3-D effect (without having to use those silly red/blue glasses!) 8-) Within 3 weeks of receiving my 17-40, I ordered the 70-200. Those two lenses will replace my whole Nikkor collection. Build is really good. The "L" zooms are a little bulkier, but very managable. The Nikkors are smaller, but very heavy. But lense technology and coatings have improved so much in 20 years, I can see the difference. I tested the lens by pointing it toward the sun. The 17-40 surprising handles flare very well. With the sun just outside the field of view, there was very little flare and loss of contrast. I also make 12x18 prints, and this lens handles them easily. The body is going to be the limiting factor (refering to digital bodies).
Warning: once you use "L" glass, you are going to be spoiled. You may not settle for consumer lenses anymore, although some non-L lenses are quick good from what I read.

I own a few L's now: the 17-40, a 24-105 and the new 70-200/4IS. This is on a par or better than all the others. Yeah, the 70-200 is really, really hard to beat, but my goodness. The sharpness, color and contrast of this lens has to be seen to be believed. Really.
I bought mine secondhand and it was a refurb. (Personally, I love refurb items of all kinds - I know the kinks are worked out!) This is just an incredible lens! Some may poo-poo the max f4, but I've used it indoors with no flash at iso800 and been handsomely rewarded for my efforts.
Absolutely a superb lens.

I have purchased several Canon lenses off Amazon, and this is by far the worst yet. I own an Olympus C-7070 and it takes sharper pictures at f2.8 than this lens takes at f12. Canon has some major quality control issues that they need to resolve, because this is not the first time I have had issues with soft lenses from them. The first lens I bought for my Canon 5D was the 24-105mm. When I received it, I had the similar issues with shapness (or lack thereof), so I returned it to Amazon and got another copy. Again, same problem. It took me sending the lens directly to Canon for calibration to get the problem solved, but who wants that kind of hassle?? Come on Canon, get it together, and improve your quality control. I love my 5D, but it should not be this hard to find good lenses from your "L" lineup...

First off, if you're a pro with a bag full of $2000 lenses, you're probably not interested in this, the 2nd least expensive "L" lens.
Secondly, if you're going to compare this to a bunch of $2000 lenses, you're barking up the wrong tree.
My guess is the typical buyer of this lens is someone who is taking their first tentative step into the world of "expensive" glass. This lens is made to order for you. It simply blows "ordinary" lenses out of the water. If you're used to the kit lens that came with your camera, or a 3rd party lens you got for $150, you are going to love this lens. You'll find yourself taking more pictures, taking time to frame your shots and basically caring about what you shoot. This is a lens that is far more talented than you are, and you'll strive to rise to its level.
I cannot say enough good things. The sharpness ROCKS. The saturation and contrast are absolutely fantastic. The focus is instantaneous and silent, and usually dead on. And the red stripe looks really cool! :)
Its heavy, and built like a tank. If you're looking for a lightweight, this ain't it. It is lighter than most other "L" lenses, however, and not too bad to carry.
Drop the 700 bucks, and go out and take some serious photographs.

great lense for any photographer shooting canon slr's.This high quality L-series lense will give you that crispness that makes a great picture. Would recomend to anyone looking to upgrade from tamron, sigma or canon kit lenses. Great results.

Excellent piece of equipment. It performs as described in its specification sheet. Expensive but the quality warrants the high cost.

Bought this lens for a digital rebel xti and it works great. Nice pictures, great for close-ups, fast autofocus but it is a rather large lens.

I can't tell you how glad I am to have finally purchased an "L" series lens. If you are considering upgrading from a Digital Rebel to a 20D or 30D you should definitely try the 17 - 40 L to be sure the quality you have been looking for is not a shortcoming in your current lenses versus you needing a new camera. I did buy a 30D at the same time, and it's a fantastic purchase, also, but my old 300D takes great shots with the "L" lens. I take the 300D with me instead of the 30D to anywhere remotely dangerous and am always happy with the results.

Unfortunately Canon does not have perfect QA, and some of us getting bad copies... or maybe body+lens do not much by some reason. I recommend sending body and lens for calibration if you get sharpness less than perfect. It is simply as sharp as 35mm f/1.4L at f5.6-f11.

I`ve used it on 5D for over 6 months. For the price it is an exceptional performer, some corner softness and distortion at 17-24mm, some vignetting and CA wide open :: nothing to worry about, especially at half price of 16-35mm.

This is my first L lens. I like the quality and durability, this is not a cheaply made lens. At f/4 I have no problem under general lighting conditions, although I do shoot wide exclusively outdoors. I've used it for long exposure, tripod night shots for which it worked beautifully.

One thing to note, this is a big, round lens. When I put it on, my camera is no longer the least bit inconspicous. It turned my Rebel into a canon. Despite the size, it does not seem heavy at all to me as a smallish female.

I admit I had a hard time justifying the price but my husband made a good point when he said the zoom range would be an equivalent of two fixed, wide angles for which I was pondering. Consider that plus the thought that this is a lens that is going to last for years. I'm expecting to pass it on to one of my children when the grow up!

It comes with a lens hood, pouch (which is not padded), and end cap. I'm just glad Canon made a somewhat affordable L lens for us amateurs who want to save up for a nice piece of equipment.

I bought this lens with a specific usage in mind: I wanted a lens which would allow me flexibility in my small studio to take wide shots without my back pinned to the wall to get the whole subject in the picture. This lens accomplishes that task with ease. The close focus distance is very useful as well and it allows me to walk around the room, stick my camera up close for great, tight portraits, or back away and get the model's whole body in focus with a pleasant cropping area left.

PROS
Wide-angle with pleasant perspective distortion at 17mm.
Rapid focusing (with sufficient light)
L-quality build
Reasonable weight and size (solid but not unwieldy)
Sharp!
Tight focal range - can get within 6-9" of a subject with the right light! makes for great perspective shots and closeups.

CONS
f/4 requires a fair amount of light. I've already struggled with this a bit.
For some reason, I keep going to the focus ring for zooming instead of the zoom ring. Something about the placement...this is pretty minor.

I have had many cameras and lenses, and as a professional photographer I highly recommend this lens. It is very sturdy and well made. Great for night or day. Great colors.

This is the first L lens I have. Solid build. Excellent performance on my 30D system. Wide angle is perfect for indoor shooting except for my baby son. He moves so fast and F/4 is not sufficient to capture his cute emotion sometimes. I believe my next target would be 50mm F/1.4.

This is an ultra crisp lens. I have been using it for almost all shots now, with the exception of macros.

I was very excited about purchasing my first Canon "L" series lens for my 30D. I had been using my kit 18-55mm lens for some time, and figured it was time to step up to some professional glass. Unfortunately, my experience was not good at all, and I have returned the product for a refund.

When I first received the lens, I took it out for a test run. I took about 100+ shots of the skyline of Seattle. The weather was partially sunny, so some of my shots had better light than others. I used a tripod and shutter release, and tested the lens at all apertures, because I had read that there were 'good' and 'bad' versions of Canon's lenses, so I wanted to make sure I got a good version before my return period expired.

After reviewing the pictures once I got home, I was quite disappointed. Most the pictures were unacceptably soft, especially around the edges. The best aperture range was between f/8 and f/11. The lens took horrible pictures above f/15, and anything below f/8 was pretty poor as well. I am an amateur landscape photographer, so it is important to me to have the edges just as sharp as the center of the picture. None (and I mean NONE) of my pictures were an improvement over the 30D kit lens, and in many cases (especially at the f/6 & f/7 range) the kit camera outperformed the L lens.

I called Canon's 1-800 number in hopes that they would consider taking the lens in for calibration (I had read on several message boards that people had gone this route and were pleased with the results). However, much to my surprise, Canon was not helpful at all. I explained that this lens was producing no better pictures (and in some cases worse pictures) than my kit lens, so I asked 'why would I spend the money on an L lens if my pictures are not improved'. Their response was that the L lens maintains an F/4 aperture at all focal lengths, this is the advantage of an L series lens. I replied that this doesn't mean much when the best pictures are produced at f/8-f/11, and their reply was 'sorry to hear that you are not happy with this product'. I asked if I could have the lens calibrated, and she told me that this would be unnecessary for a new lens right out of the box.

So I then contacted the 3rd party vendor that Amazon shipped the camera from, Ace Photo and Digital. I explained my issue and they offered to replace the lens. I was happy to give this a shot in hopes that my replacement lens would produce better images. I received the new lens a few days ago, and again took it for a test run. Exact same results. So I am sadly returning the lens for a refund. I appreciate Ace Photo's assistance and thought they were very professional.

I really wanted to be pleased with this product. There are several reviews on Amazon.com stating how sharp this lens is, but I just didn't see it in either lens I tried. Maybe I got 2 bad copies, but what are the odds of that?

Very nice,very good quality.
Buy it from amazon and save your money.Showed a very good to excellent performans.12 elements in 9 groups.77 mm filter size.27-64 mm standard zoom on full frame cameras.

I purchased this lens last year when I switched to Canon after over a decade of using Nikon SLRs exclusively. I use my digital SLR primarly for travel photography, keeping a point and shot in my computer case for day to day photos. I have used this lens for 90% of the pictures I have exposed with my digital SLR. Extremely sharp and of high quality construction. Feels like a heavy glass brick. Makes the allegedly high quality Nikon lenses I sold seem like junk. The lens feel heavy and large on the camera especially with the not-included lens hood. This lens hood is a must because that large 77mm front element seem to attract stray fingers and hard objects. After buying the lens hood separately, I found it too large to conveniently carry. I bought a non-Canon collapsible rubber hood which offer less protection but is always on the lens. While not cheap it a bargain for Canon's top-of-the-line "L" series lenses. This lens is a must-have if you're serious about taking good pictures. Throw the kits lens that comes with most digital SLRs away or just don't buy it in the first place as I did.

An earlier reviewer gave this lens only one star. He may have been incredibly unlucky to get two bad samples, or perhaps his AF was failing to find precise focus.

I do not own this lens, but had the pleasure of using it for a week with a borrowed EOS 1D Mark II when that camera first came on the market. I found that it gave extraordinarily sharp results, with little light fall off in the corners, hardly any propensity to flare, and virtually undetectable chromatic abberation. The only duff results were entirely attributable to my poor technique. Considering the quality of construction and focal length range it is lighter than you might expect. On top of all that it is sealed against water and dust.

It will be the SECOND lens I buy when I eventually decide on which of the EOS bodies is best suited to my type of photography (the first being the new 70-200 f/4L IS USM)

I purhased this lens just prior to a 10 day trip to Yosemite. My previous trip told me that my 24-70L wasn't quite wide enough. I had pre-ordered the 16-35L II but the delivery time was pushed and would not arrive in time. Therefore, I cancelled it and purchased the 17-40L instead. Landscapes don't require a 2.8 anyway and the 17-40 had great reviews on the wide end, just where I was to use it. The lens arrived two days before my departure and had large dust particles in it. I tell myself "OK, I'll process them out because I don't have time to return it." For three days, I'm tickled with the rich colors and overall sharpness. I got some great shots as it was my go-to lens. While on a hike to Vernal and Nevada Falls, my 1D2 quits reading aperture settings on the 17-40L. I depress the shutter and it remains open for about a minute in bright daylight then receive the Err01 message. I switch to the 70-200 F4 IS (fantastic lens) and the camera is reading just fine. However, I now have serious banding across all subsequent frams and the 1D2 becomes unuseable. Canon USA tells me the problems are unrelated, which the laws of probability state otherwise. So, I'm bittersweet about the lens. It is the best value in the Canon line and worthy of the L designation. I believe this one just slipped past quality control, which is rumored to be spotty. I've used Canon Factory Repair-Irvine in the past and have been very happy with the service and promptness of repairs. The bright side is I'll have a perfect lens upon return. However, I'm very upset about the missed opportunities and the cash outlay just to sit around without my primary gear. And if Canon charges me for repairing the 1D2, I'm going ballistic....aaargh. All of this said, I have been very happy with my Canon equipment and use it unafraid of conditions. It has always prevailed, until this. And this is why backup gear is a necessity. To top the week off, my laptop croaked. Thank goodness for external hard drives! What a week.

If you want a good all around lense and can't afford the canon 16 - 35 mm lense this is the one for you. I have taken it out for a test run and shot about 40 pictures and all came out great. I use a canon digital rebel camera.

I bought this lens to replace the kit lens I got with my RebelXT, all I can say is that it's worth every dollar i paid.
Sharp, fast Auto Focus, great build, looks good, feels good and delivers the quality image I expect from an "L" series lens. This is my second "L" lens and both have delivered handsomely.

This is one of Canon's best deals as far L's go. I use this on a full frame 1Ds for wide captures and on an XTi for use as a standard zoom. The F/4 aperture is something you'll just have to work with and the image quality is very good. The lens is incredibley tough. For a cheap price you're getting a lens that can withstand a drop from about 5 and half feet and still be good. I droped this lens on concrete - it landed on the front lens cap corner and then landed again on the rear lens cap corner. It still performs like a charm. You see.. this lens will last you an eternity.

Although this lens is considered as ultra wide lens, for XTis and 30D's, this is really a 28-65mm lens (not "ultra" but regular wide). I purchased this for about $700 at Amazon to replace the kit lens 18-55mm the XTi came with. I am very pleased with the photos that I am taking. The focus is quick. The images are sharp, and the color is beautiful. I like the lens a lot. Because it's a F4 lens, I do need to use the flash. With 430EX flash I am getting pleasing shots in low light situations as well. I suppose a lower F stop might be better but I don't think Canon makes a lower F stop lens of comparable build. I did consider 28-70mm F2.8L (45-112mm on the XTi), but then it's no longer a "wide" angle lens. Compensating for the crop factor, getting a wide angle lens meant 17mm or less. So, this was really the only choice I had for an L quality build at this price range. Over all, I am very satisfied with the build quality and the results. The 40mm (64mm on the XTi) is a bit short, and I wish it were longer. However, giiven that this lens costs only (did I say "only?" lol) about $650, I have no complaints about the lens. Something's gotta give. It's weight is nicely substantial (not too heavy), and since I use my XTi with a battery grip all of the time, the combined weight balances well in my hands. To me, the battery grip and this lens are perfect companions to make the XTi's complete. I like this 17-40mm f/4L USM Wide Angle Zoom Lens for my XTi.

I'm rewriting this review as my previous wasn't helpful and I was ticked when I wrote it. Upon purchasing, I immediately left for a 10 day shoot in Yosemite, CA. On day 3, the lens failed and sent an Err 01 code to my 1D2. This failure left the aperture open and damaged the camera sensor. So my primary rig is down and I'm more than upset. I own other L lenses and have had this body for 2 trouble-free years. Canon USA Repair Center-Irvine rectified the problem in a week for which I'm thankful but charged me labor fees on my out-of-warranty body. Hmmmm. The lens exhibited back-focus issues and had dust particles inside the body which Canon USA has remedied. OK, on the the lens review. Please note this is three days of shooting but hunderds of critical shots. I'm unable to compare to other brands but can relate to other Canon L glass.

Color: very rich and saturated. This is a big reason to buy L glass.

Contrast: very high. I used a polarizer to enhance most of the shots.

Filter Size: 77mm which is the same as the my 24-70L (thus negates buying more if you already own this size). I had the new 16-35II on order but cancelled it as I didn't need the 2.8 or the cost of buying all new filters.

Weight: Relatively light. A big plus when lugging it up/down mountains.

Focal range: on my 1.3 factor body, it's not that useful for me other than the wide end. The range is not great for portraits as it distorts (see next category) and makes facial features more pronounced, like noses for example. This is not flattering to most. The 24-70L is a great choice for portraits and general purpose.

Lens distortion: Pretty significant barrel distortion at 17mm (particularly on close objects) but can be post-processed. Some pin-cushion at 40mm as well. This is my main complaint but it can be fixed. Just be aware you will spend some extra time on it.

Price/Value: A++

Build Quality: I got a lemon which happens to any manufacturer. They quickly fixed it and I learned a lesson. NEVER take unproven gear to the field without a backup. I've got backup stuff but this was a catastrophic failure for my trip. Canon has known issues with focusing so test your gear. They are still the best lenses available.

Focus: Very fast. Mine however, was not accurate and required repair.

Aperture speed: I bought it for landscapes on this particular trip and an ultra fast 2.8 is not needed here. The F4 is just fine and adds to the weight savings. You will need a flash and/or higher ISO for indoor shots.

Weather sealing: I need this feature and is a major factor for my purchases in L glass. If you dont have a 1D series body, this feature is of little importance. This feature works, trust me.

Sharpness: Very sharp (mine just wasn't accurate)

Overall: It's a great lens if you get a good copy. If not, have no fear. Send it to Irvine and it will come back perfect and in short order. However, it is an inconvenience in the least or a major disruption as was my case. I personally don't feel it's a great walkaround lens. The 24-70L or the 24-105L are more useful but heavier. Therefore I cannot give it a 5 star. For landscapes, it't the lens of choice out of the zooms. On the 1.6 bodies, the 17-55 IS is a better all-around choice but a few bucks more (and money well-spent) IMHO.

I hope this review was more helpful than my last.

This lens takes pictures as though the lens has a cataract. I know it's not a prime, but I would think for an L series, it would take better pictures. I have a prime 20mm & 50mm F/1.4 which takes razor sharp pics in comparison.

I just read another review which states Canon sometimes ships lemons which need adjustments. I will be contacting Canon and give an update on the outcome.

On a side note... This lens feels very well made, is light, short, and ultra fast. I just wish is was sharp.

Great lens for the beginner as well as for the seasoned pro. Razor sharp images.

This lens is really sharp and feels really solid. Weather sealing is a nice touch too. I would have gotten the 16-35 f2.8 if i could afford it, but i don't regret getting this one a bit. Besides, if you want a lens for landscapes, you won't need something at f2.8 anyway. Save the money and get a fast prime for low light stuff.

This is my first L lens, and as others have said in these reviews, it certainly causes an addiction to the highest quality glass Canon has to deliver. Everything said about quality in the image and focus speeds is correct, as this lens in amazing!

My only fault with this lens is that a 17-40mm range is just not good enough to be a full-time walkabout lens, but I knew this before getting it. My current use for it is as a lens on my second camera that hangs from my shoulder as I shoot events, and an excellent lens it is for that purpose! I suppose, paired with the 70-200/f4L it would work great, but you see there this is more of a combo lens than a solo workhorse, at least in my opinion. Fortunately, carrying two cameras is something a lot of photographers already do, and using this lens as part of a combo team just makes you even stronger with your capabilities as a photographer.

I have this lens on a Canon 30D. First it soft focuses; I sent it back, but after a repair, it still does. Second, at 24mm on a 1.6x sensor, that translates to 38mm, hardley very wide angle. At 105mm it's really a 168mm, barely a telephoto. I did Europe with this lens as my walk around. The wide angle wasn't enough. I'm disappointed; I have a 17-40mm L and a 70-200mm L for vitually the same total money as the 24-105mm L coming. The real issue is: Canon doesn't have a really good, high quality walk around lens. Because of this, If I could do it again, I would buy the Nikon D200 with the 18-200mm Nikon lens.

If you are going to purchase this lens then you have read the reviews. It is all that people say. F/4 is a little slow but it is a short lens so low light shots hand held are possible with a steady hand. Great build, nice weight, great lens.

this lens is good
very sharp
and very good
but not enough zoom range
and it is only for full frame machines
especially for film slr s
because in a crop factor dslr it is not enough and it is not wide enough..canon 10-22 is more good than this
for a full frame there is some vignettint issues and corner softness..so this is only good for film slr
if you have rebel series or 20d 30 d go with canon 10-22
if you have film slr buy this lens

I have had this fabulous lens for 2 months now. This is my second lens in Canon's line up of L lenses. I have a 70-200 f4 non-IS also. This is my first wide angle zoom L lens and i have come to know what i have been missing. Till now the widest lens i had was a 50mm f2.5 macro and 50 f1.8. Although on a 1.6x sensor like 20D which i own, this lens is not so wide it performs excellently. The focusing is very fast, sharp crisp images and consistent quality as the aperture range remains the same throughout the entire zoom. This may not be suitable for some the semi-pros or pros since its a little slow being f4, i would recommend this to anyone who does serious photography as a hobby. In indoors too it performs flawlessly. Most of the time i dont use a tripod and its difficult to maintain a fast enough shutter speed especially with aperture more than 8. so if you are like me, then you may want to take a look at the 17-85 IS or the 17-55 IS since the IS compensates atleast 2 stops in low light for hand holding. But if its outdoor then u can easily handhold this and shoot some great photos in good lighting conditions. Also i would like to mention that being a L lens this is a little heavy because of its solid construction. Its also big compared to the other startup lenses. It takes 77mm filters and it can be used even on full frame cameras like 5D. hope you enjoy this lens as much as i am doing.

Okay, nobody is going to rate this as a good review, because I am not going to elaborate.

Basically, I love this lens. Love, love love love love. I am a fan of having a zillion lenses, and if you are too, you should probably have this to add to your collection. I have 7 lenses for my old 35mm Olympus, and wanted to outfit my 30D with all those fun things. So, I did. This is my favorite of all my lenses I own. I haven't found a single problem with it yet.

The only hassle is finding 77mm filters. A lot of places don't go that big.

Perhaps it's always true of wide angle lenses (i'm still new to this arena), but this lens seems a little dark, a little sloppy, just not quite good enough. With the exception of a few panoramic lake-front or ocean-front shots, i've seldom been pleased with the results. In contrast, i love the photos i get from my not-L-glass Canon 100m macro or my similarly "inexpensive" Canon 70-200L f/4.0 (which has amazing color rendition and excellent boca). It could all be my fault, but i think this lens just isn't sharp enough (despite its L-glass designation), and the color isn't rich enough. Sure, there's always post-production, but i hope Canon comes out with a better wide angle lens in this price range.

"Great lense and very sturdy. I bought it for our to trip to Seattle, Victoria, and Vancuvar. It took great pictures. A bit pricy, but no regrets. Now I want to buy the telephoto lense."

I got myself a 30D and after hearing all reviews about the kit lens decided I should upgrade to an "L" series lens. I did a side by side comparison on a tripod of the 17-40mm L vs. the 18-55mm kit lens. I used different apertures and focal lengths. Overall, my opinion is the the 17-40 is better. However, it was not, in my opinion, a huge difference. At some settings, I really had to look hard to find some differences. Don't forget this is just a subjective test. Perhaps I was expecting more from a lens that cost me almost $900 CDN. For me, the jury is still out on whether it was worth the amount I paid.

I bought this lens after contemplating buying the new 16-35 2.8. I had the money to buy the more expensive lens but I didn't and here is why. I was told by an aquaintance who test for Canon that the 17-40 f 4.0 is over all sharper and has less distortion than the new 16-35 f 2.8 (as of Aug 15 2007). I have heard this from other photographers as well. Also although it isn't an f 2.8 as like the 16-35 it does have a bit more range and I have found the focusing is pretty fast regardless. I think it is the best $700 I ever spent on a piece of camera equipment.

I purchased this lens specifically for wide angle shots. The image quality and sharpness are what I expected from a Canon L Series lens. If you're looking for a reasonably priced, wide angle Canon L Series lens, you should strongly consider the 17/40 L.

I've gotten so many nice complements on pictures I've taken with the Canon EF 17-40mm f/4L USM Ultra Wide Angle Zoom Lens. The pictures are crisp and sharp. Canon does not disappoint!

I purchased this lens to use on a Canon EOS5D, full frame 12.5 Megapixel digital camera. This is my favorite lens! The expressiveness of pictures taken with it is beyond description. It bring the viewer fully into the scene, almost as a virtual reality setup. I think the best next thing would be an IMAX type lens with the appropriate displays... but that is beyond the scope of us mere mortals.

I use the lens for aerial photography and for taking pictures of my favorite subjects: airplanes. In Airventure 2007, at Oshkosh, WI, I didn't have this lens and I lost several very interesting pictures for the lack of it. I purchased it shortly thereafter. On a recent trip on a Cirrus SR22 with a friend, I took dramatic pictures of my pilot friend doing his preflight, and once in the cockpit, doing all his clearance and pre-flight chores. The pictures do do justice to the reality of the scene, even when you take a composition of the airplane panel with the view outside the cockpit on the same picture. Some Photoshop - Shadows and Highlights - is all that is needed to bring it all into the dynamic range of the photographic papers we use.

This is my favorite lens because of its perspective, the reality view you get at the 17mm extreme. For my girlfriend, this is her favorite lens because it's the only L-lens I have that's below 1 pound!

NOTE: The lens hood is almost useless. Be careful with flare of the sun hitting the lens or a filter. The circular polarizer introduces weird artifacts because of the wide angle - part of the sky will be dark, part will be bright... better not use a polarizer.

The other lens I have, all L-glass from Canon:

* 70-200mm f/2.8 L IS - for the best airshow pictures you can fathom! Extremely fast lens, it works with the Autofocus on the 5D in the sub-second range, letting you use it almost as a point and shoot. Your only concern is the framing, everything else is done by the camera + lens.

* 24-70mm f/2.8 L - extremely fast, extremely sharp. Sharp as a tack! If you take portraits of women, you will need to use the "heal brush" in Photoshop a lot, this lens doesn't forgive any wrinkles, pimples, large pores on the skin. For night scene photography, just let the camera at ISO 800 and you can do without a flash, for indoors night photography, even in an extremely dim restaurant.

* 2x Extender - OK this is not a lens but it's an accessory that makes my 70-200mm into a 140-400mm f/5.6. AWESOME! At Airventure it's used to take pictures of the planes at the extreme end of the runway getting ready for take off. Or for capturing the vapor trails on the leading edge of the F22 Raptors as they defy the laws of physics. For daytime use unless you have a tripod and the scene accepts a 1sec or more exposure.

I like landscape and interior photography and this is definitely my favorite lens of those I own; with the 10D's 1.6 crop factor this lens has a nice equivalent range of 27.2mm - 64mm.

I use it all the time and the images are nice and sharp--considerably better than the images I got from the Sigma 14mm.

If you're into portraits 64mm (with a 1.6 crop factor) is maybe a bit too short but for landscapes and interiors I would highly recommend this lens. I love it.

We travel a lot for our wedding and travel photography and we utilize this lens quite extensively.

Canon's 17-40mm f/4L lens is one of the most affordable and lightest L class lenses out there. We also utilize the more expensive Canon EF 24-70mm f/2.8L USM Standard Zoom Lens for Canon SLR Cameras; however, this particular lens is a favorite among female photographers who have smaller grips.

PROS
----
1. The lightweight design allows you to take photographs without getting any aches and pains on your wrist.
2. Maintains f/4 and consistently sharp picture across the 17-40mm range.
3. Relatively low cost.

CONS
----
1. You will need to adjust to a high ISO or have good flash in order to take good shots in low light. This isn't a problem for 20D, 30D, 40D, 5D, and up. Rebel XT / XTi users will need to utilize a noise reduction program.

Don
Refined Touch Photography

I like the fact the lens does not extend when zoomed. It is well built and not too heavy. It is typical L build quality with nice optics. Not a lot sharper than the Sigma 18-50 EX lens I bought this to replace but if sharp was all I was looking for I would have been disapointed, I like the rugged feel and the weather proofing. I also like the full time manual focus. I plan on upgrading my body with a full frame sensor and when I do that I think the lens will be even sharper.

I struggled for weeks, maybe months, on the lens to buy to replace my kit lens, something light enough that I won't want to leave it at home when I'm going out for the day. I rented a lens that ended up feeling like it was 100 pounds, and I just didn't think the photos were impressive enough to pay upwards of a thousand dollars.

I visited lens-specific flickr groups to look for the photos that jumped out at me the most. Everything I saw on a 17-40mm group jumped out at me, and I took a chance on this lens, even though 40mm seemed a little short and it didn't have IS. But I am SO thrilled with this lens, that I have forgiven it for not having IS, and if I need to take photos inside, I'll use my 50mm f/1.4. I have realized that you just can't find one lens that will meet the need of every shooting situation. I'm extremely happy with my purchase.

The Canon 10-22mm EF-S wide angle zoom or the 17-40mm EF "L" zoom? I deliberated this decision for over a month, having physically tested both lenses on my 350D crop frame DSLR at local camera shops and spending a near ridiculous amount of time reading through indispensable online reviews such as this one. With the price for each being roughly the same, the decision came down to the 10-22's ultra-wide capability vs. the 17-40's build quality.

I ended up choosing the 17-40 and here's why:
-Incredible optics and sharpness. If you're like me and have never owned an "L" series lens before, you'll be able to see the difference in optical construction quality before you ever snap a digital shot. It's evident in the viewfinder just how precise this lens is.
-Longevity: I'm the kind of guy who likes high quality equipment and can see myself upgrading to a full-frame sensor camera body sooner rather than later.
-Wide vs. Ultra-wide: You'll often read warnings of the difficulty in framing sub-20mm ultra-wide compositions. It's a valid point. Only certain scenarios lend themselves to 180 degree framing but most of the time you'll be challenged to keep all of the uninteresting junk out of the frame. I was a little worried about 17-40mm's 27-54mm conversion when used on a crop frame. Would it be wide enough? Answer, yes. 27mm is plenty wide for most applications and with the crop factor, I get almost zero barrel distortion at the widest edges. In my estimation, the 10-22 is more of an effect lens whereas the 17-40 is much more of an everyday multi-purpose working lens.

In summary, if the focal length range of the 17-40 doesn't overlap too much over your current lens kit and you favor high-quality wide over good quality ultra-wide, then this lens is right for you.

*NOTE: If the 17-40's inclusion of a lens hood is influencing your decision in anyway over the 10-22, don't let it be. The hood is basically a pain in the rear due to it's ridiculous size and shape. Difficult to pack and you'd probably be better served just picking up a 77mm protection filter.

This lens performs very well. It is sharp, has limited distortion, and controls chromatic aberrations well. Color reproduction is also very accurate. The more I use this lens the more I like it. The only slightly negative thing I can say about this lens is the dust sealing could be a little bit better.

Pros:

Very nice lens bag included
Love that high quality L Lens build
Lens hood included and easy to install
Great contrast, beautiful rich color images
Super quiet and super fast USM auto focus
Buttery smooth zoom and manual focus rings
Fits all Canon EOS cameras including full frame film and 5D
First copy I got was good to go with no quality control issues
Razor sharp images: sharpest lens I have had on my Canon Rebel XTi to date

Cons:

Only F4, wish it was F2.8 or even F3.5
Lens Hood is very bulky and hard to store
Rather narrow 17-40 zoom range: 17-55 would have been nicer

First impressions:

If you are an older photographer like me you remember the good ole days when all SLR 35mm style lens had a quality feel to them. Built to last forever with smooth zoom and focusing and they came with a lens hood and carrying bag. Details included a built in lens focusing scale in both feet (green lettering) and meters (white lettering) and an infrared scale adjustment in red lettering. The lens mounted to the camera body with a precision feel like the two were actually made by experienced craftsman who actually cared about the product they were creating. With this Canon EF 17-40mm f/4L USM lens that's exactly what you are getting, a finally crafted functional work of art.

I never cease to be amazed at USM auto focus, so quiet, so fast, so accurate, so useful with the auto-focus manual focus override without turning off the auto focus. I shoot both wild life and weddings both of which require at times the camera be as quiet as possible up to the moment you shoot. This lens delivers; I can barely hear it focus even with my ear against the lens and can not hear it focus at all only a couple of feet from the lens.

Decisions Decisions:

Like a lot of other people I was looking to upgrade my basic Kit 18-55 lens (very soft muddy lens) I got with my Canon Rebel XTi camera. And like a lot of people I wanted a lens that I would never outgrow or tire of or wear out. I take a lot of photos and frequently upgrade camera bodies and wanted a lens that will also work on a full frame camera like the 5D.

I had borrowed a friends 17-70 Sigma and it was really sharp and for the money (less then half the price of the Canon 17-40) I thought I would try one even though it wouldn't work on a full frame camera. I went through two copies and both were bad before deciding to go back to the 17-40. Man what a great decision going with the Canon 17-40. Thanks to 47th Street photo for being so nice about the whole return twice then later upgrade from Sigma to Canon situation. I only had to pay return shipping.

Testing:

When I received my new Canon 17-40 I took it out, mounted it on my Canon Rebel XTi and mounted the camera on a tripod, put on a remote release, set the camera to mirror lockup mode, Aperture Propriety at F8, 28mm zoom and tested it both against my friends Sigma 17-70 and my own basic Canon 18-55 kit lens. The 17-40 absolutely blew the kit lens out of the water: in sharpness, contrast and richness of color. Then I tried it against the Sigma which I thought was a sharp lens and the Canon 17-40 was sharper and had more contrast then the Sigma. Then I set it to 40mm and shot against my Canon 50mm F1.8 II lens which I thought was pretty sharp and it was better then it as well. I then tried the lens in various conditions and settings and all extremes both indoors and out with and without flash. I also own a Canon 70-200 F2.8 L and it's sharper then it as well.

I was very pleased to find out that the very first copy of this lens right out of the box was razor sharp and right on the money!

Conclusion:

This is THE lens which I will test all others I purchase. If you want THE best wide angle lens to use on both cropped and ultra wide for full sized sensor Canon EOS camera bodies this is it. It's dual purpose capabilities both as a normal walk around zoom (27mm to 64mm) on cropped sensor cameras and ultra wide zoom (17mm to 40mm) on full sized sensors make it a very versatile lens you won't out grow.

I am very pleased and heartily recommend the Canon EF 17-40mm f/4L USM Ultra Wide Angle Zoom Lens.

Other lens owned:

Canon EF-S 18-55mm f/3.5-5.6 Rebel XTi Kit lens Muddy, slow, pile of junk
Canon EF 17-40mm f/4L USM Fantastic sharp work of art
Canon EF 50mm f/1.8 II Great portrait lens
Canon EF 135mm F/2.0 The best portrait lens