Strobe Arms...

Before I start, I just wanted to say that I have already read through the strobe arm forum above, and understand the standard lengths recommended.

I am in the process of setting up my first full underwater setup for my Canon 40D. I just ordered the Ikelite housing, 8" port and along with it a DS-160 Ikelite strobe package. The strobe is the first thing that has come in, so I have not connected it up to the housing yet to see how long the arm length will be, but at a glance, I am thinking the standard arm length is too short. I believe Ikelite ships it with a small 5" part that connects to the housing and then a 6" arm to the strobe.

I am planning on doing only wide angle work underwater on my upcoming trip in May to Honduras, and I only plan on having the one strobe, which is why I purchased a more powerful 160 strobe. I am still on the fence and thinking of just trying out the standard arm length that it comes with and seeing what I can make happen, but given my setup with one light and WA work, do you guys think it will just be impossible to make it work? If so, what should I consider for arms? Should I replace the entire thing and go with another company to get a more standard 5X8 setup? Unfortunately Ikelite does not sell an 8", so I would have to get a 9" arm if I went through them, which would put me at a 5X9 I am guessing. Any feedback is greatly appreciated.

Try to get a couple of dives with it, even in a pool, before your trip to check it out. Longer arms, or adding another will give more flexibility in strobe positioning but I used the single strobe Ike package (3944.90) for over a year until I got a second strobe. Because you are mostly using the strobe above the camera, the length of the quick release ball arm contributes to strobe / port separation. When positioning the strobe out to the side, typical to a twin strobe set up or maybe when shooting portrait, it won't. Similarly for close focus WA you might find yourself needing to pull the strobe back a touch for more even lighting which will also tend to reduce the port / strobe separation.

Consider rig buoyancy on your test dives. It maybe that its considerably negative, in which case an additional buoyancy arm or adding a foam will greatly assist comfort.

I have recently gone over to Ultralight 8" + 12" float arms with the very short BA-1K quick release ball arm on a dual strobe, Ike housing, 8" dome setup .

Thanks for the info, very helpful. I just got the housing in today and after setting everything up, I connected the arm to the housing and I think the length is actually really pretty good, so I think I am going to go with it. With one light above the housing, it seems to have enough reach. I will try it out in the pool, but will also probably shoot with it on my first trip and see how it goes.

So the strobe arm does not have any buoyancy compensation in it? Does the foam you suggest wrap around the arms to add buoyancy?

I use 8 and 12 inch arms. I mix all the brands. 2 8" on each strobe for macro. An 8 and a 12 on each strobe for wide angle. Even works with the 10-17.

...So the strobe arm does not have any buoyancy compensation in it? Does the foam you suggest wrap around the arms to add buoyancy?

Yes, The Stix make float segments that slide over the arm but quite pricey (imo) for a bit of foam. Article in here :- http://wetpixel.com/i.php/full/review-of-s...-by-cor-bosman/

also http://reefphoto.com/index.php?main_page=p...roducts_id=2320

If you're on a budget or just want to experiment first, get one of those tube things that kids use in the swimming pool. Its not as good because it compresses a bit at depth but, hey, its only a couple of dollars.

Balrog, do the Stix float arms work on the Ikelite circular strobe arms? The picture shows them being put on a ULCS arm, but are they pretty easy to just rig to fit the Ikelite rounded arms?

Is the only other option to completely replace the 6" Ikelite arm with something like a ULCS arm that has better buoyancy? I think I will definitely need to do something, because I have the same problem others have mentioned. The DS-160 is quite heavy and the locking bolts on the strobe arm are tightened quite a bit and still I have problems with the strobe bending the arms. I think underwater at least with a little bit of buoyancy help it should be better. I'm just struggling on which route to go.

You are correct, the Stix floats won't fully fit the Ike arm properly, but neither will they fall off.

You will see all sorts of buoyancy creations from coke bottles & zip tied foam blocks - through to posh proprietary kit.

I suggest you get a cheap kids flube and try it in the pool before deciding. What works for one person may not work for another.

if the flash is severly negative i prefer to add the buoyancy to the flash directly so that it can be re-positioned without changing the balance of the rig

i'm not an expert wide-angle shooter, but i found an enormous difference between one and two flashes