Hi there
I’d say you have two main options:
1 - use the Ikelite sync cord and control the strobe manually or use External Auto
2- use the optical cable and use the Inon sTTL.
I shoot a rig using Ikelite’s manual controller, so I don’t have any form of TTL as an option. In general I haven’t found it that troublesome to experiment a little with each shot to get the strobe power set for correct exposure. With my Canon S70, I have found good results (at least I consider them good!) by using Aperture priority mode on the camera, with forced flash.
This means the camera’s flash always fires, and so my strobe always triggers. I can mess around with the aperture, which I do primarily to (crudely) control depth of field. I manage exposure by controlling the strobe power level. After a couple of dives, I have found I can preset the strobe power for a given situation with reasonably accuracy based on the distance to the subject and the type of shot I am trying to take. Minor tweaking can be done over a couple of shots to fine tune the exposure.
I think you’ll probably get used to the manual setting approach quite quickly. When you get down to it, there aren’t as many settings to control as you think. To trigger the strobe, you need your camera to fire its own flash, so you will probably use forced flash mode. This means the camera will probably pick a shutter speed of 1/60th because this is the flash sync speed, so you won’t be able to (or need to) adjust the shutter speed. One variable fixed! So you only need to think about aperture and strobe power level. You could initally just pick a mid range aperture and leave it at that for the whole dive, which leaves you with just strobe power to think about.
Of course, you will always have to think about strobe positioning: you can vary the distance the strobe is away from the subject which affects exposure, and obviously the angle of the strobe lighting and its position has a significant effect over the look of each picture. This is probably where the most experimentation and learning from experience will come in.
Finally, I don’t use an Inon strobe, but as far as I can tell, the External Auto option can be used as you describe in your question 2.
To some extent it is probably inescapable that when you first use an external strobe (or pretty much any other u/w photography accessory) your results will suffer until you get used to the new kit. I certainly found my pictures suffered for the first couple of dives with a new strobe. Shortly after that I figured out how to use it better, and my photos improved again, this time exceeding what I could achieve without the strobe. You may find that you have to go through this ‘pain’ and get some experience with the strobe, try out a few different ways of using it, and settle on a workable approach for you.
It sounds like you have the gear on the way, so the hard decisions are already made (i.e. what to buy!), now all you need to do is get in the water and play with your new toys. The beauty of digital is that you have nothing to lose by experimenting and trying new things out. If the shot doesn’t work out, delete it and try something else!
Anyway, good luck, and have fun with your new kit - it certainly looks a nice rig to me.
cheers
Graham
