Anyone have any first-hand experience or opinion regarding how successfully the Sigma 105 or Canon 100 macro lenses could be used underwater with autofocus? I wonder if the aiming lights on DS-125's or other strobe aiming lights would be adequate to successfully assist in autofocus during low light and night diving. :?:

Hi Meister,

I use the Nikkor 105 which is also an f2.8 lens and I often shoot it in autofocus. I know it's not a Canon or Sigma lens, but I think it's very similar.

I would describe the autofocus on ANY of these lenses as "adequate." It works pretty well during the day. Morning/evening and night require extra light to focus. If you don't mind pointint your strobe straight at the subject, then the strobe modelling light (Ike 125 and 200) works pretty well.

Otherwise, you might want to use a dedicated modelling light mounted on the housing. Does Ike's new housing have a "coldshoe" on top like the MD case has?

Good luck, I'm sure you'll get some posts from Canon shooters too.

Cheers
James

Both the Canon and the Sigma (50) focus fine with my 10D. I use a small UK light mounted to the "hot shoe" on the housing and it works great.
BVA

one note,

when using the lens at 1:1 for macro shooting with moving subjects (or in surge ), manual focus usually will allow you to get more shots. The limited DOF tends to put the lens in a constant "searching" mode because it can't maintain focus long enough to "lock" in and allow the shutter to realease.

CB

AF on Canon 100 mm macro worked fine for me. It did search some when swiching from 1:1 ish to <1:3 but once it gets close it doed great.

Thanks for the responses! I don't know about Ike's new housing having a "coldshoe," as I don't have one, yet anyway. I'm assessing the probability one of these 100/105 lenses will successfully work in the Ikelite housing. I don't believe manual focus is an option, but I certainly stand to be corrected.

I've used the Tamron 90mm 1:1 macro on Canon underwater, but wouldn't recommend it if you're trying for AF - this is one of the few areas where the more expensive Canon 100mm macro is superior to it.

On our last live-aboard charter I had a Canon 100 USM and one of our guests had the Sigma 105. She complained of inability to autofocus so we did side by side comparisons, topside, around the boat. The Sigma was way slower than the Canon, and in some cases would not autofocus when the Canon would.

I agree it may not be as much of an issue with the 50, and in fact with the Sigma going 1:1 and the Canon only 1:2.5, maybe the Sigma should get serious consideration. But Canon versus Sigma at 100mm, Canon rules.

Thank God.

I finally convinced my wife to let me go DSLR, I talked to Watt and Haas on which lenses to get and got them. And, good news, same ones you mentioned here.

Canon 100
Sigma 50 for the 1:1
And, the Sigma 15fe. I was informed the price difference did not warrent the Canon.

Oh, and the kit 18-55.

Now Steven, if you can send a little letter to Canon to kindly ask them to free up the locked focus functions on the Rebel now that Nikon's answer to the Rebel has that ability, I'd be tickled pink!

Thanks for the response(s). Interesting you would state this. I did order and subsequently received the Sigma 105. I ran the 105 through its paces with autofocus. I suspected it might have difficulty with autofocus underwater, at least had the potential to possibly struggle in low light situations.

I researched all I could find on these two lenses, which resulted in me sending the 105 back. I ordered the Canon. The brown truck delivered it a few hours ago. I've been working with it these last couple of hours in and around the house. Well worth the extra $140! IMHO this is an incredible lens. I concur 100% with your aforementioned comments.