I'm on the hunt for a decent zoom lens for shooting medium size critters (reef sharks, eagle rays, etc.) for my Canon 20D. There are a number of options available from the likes of Canon, Sigma, Tamron, etc. So far I've considered the Canon 17-40L 4.0, the Sigma 18-50mm 2.8 and the Tamron 17-35 2.8-4.0. They all seem to have good to decent reviews in comparison with each other.

What I would like is some real (underwater) world comparisons with which to make my final decision. Does anyone have any of these lenses who can offer their opinion about its use underwater? Any other suggestions on any similar lens to use that I might have overlooked?

Thanks!

Laz: you might also look at the Tokina 28-70 2.8 which is very good for the price (~$250) but don't know if it fits into your criteria.

Cheers
James

I have the Canon 17-85MM and it's a great lense. Very good in low light conditions, wide enough to get the bigger stuff and small enough for the smaller things. You're suppposed to use it behind the dome port but I use the flat, you have to back if off it's widest a mil or 2 but others wise it's great. I use the flat because it's smaller, the 8" dome is huge with the dome shade on.

Lazaruuu.......

I also have the Canon 17-85mm IS lens and just received the special Ikelite dome port allowing complete range zooming with it.

Will be shooting it on my Rebel XT the next two weeks in the Bahamas. I borrowed my brother's lens before buying one myself. Very fast USM focus (even without the IS turned on) and sharp!

In dim available light shooting it really is incredible (I think I read this is 2nd or 3rd generation IS.) Just have to learn when / where to turn the IS on and off....

I'd suggest going to a camera store and trying one out...

Dave Haas

David,

did you use the lens without dioptre?

regards,
Julian

Jolly,

Will use with a +4 diopter (B&W made in Germany one) for full range zoom behind the Ikelite extended dome port #5503.90 as recommended by Ikelite's site. This lens does not focus to 1' or closer thus needs a diopter to see a dome port's apparent image behind the Ikelite dome port.

The Ikelite dedicated port for this lens is surprisingly compact! "Dunk test" tomorrow then dunking in warm salty Bahamian water this coming Sunday

Search the threads for previous discussions about diopters, various strengths and numerous opinions. Lots of ideas out there!

dhaas

that's what I was guessing because there are other lens solutions for those preferring dioptre less operation (like me).


yes, and I've put something together in this article.
http://wetpixel.com/i.php/full/dome-theory/

Julian

Hey Laz,

I've got a 17-40 and will be bringing it on Shear Water for our shark trip. I've seen mixed reviews of the Sigma 18-50. Supposedly very sharp in the middle but the corner sharpness and vignetting seems to be an issues with some copies of the lens.

Mike

I think I might have a quiet OK copy of the Sigma 18-50mm f2.8. I like the lens a lot and use it underwater as well. I only experience noticable vignetting @18mm and @f2.8. A little bit more reach, one f-stop faster, and less expensive compared to 17-40. But no full frame lens and to some not up to the 17-40.

regards,

Julian

edit: 17-85 @17mm and wide open is the king of vignetting and CA
From my personal experience the 18-50 2.8 is better in terms of optical quality than the semi-megazoom 17-85 (which I've tried a few days with a 20D) and focuses down a little bit closer (I use it without dioptre). But doesn't feature the range, IS and USM.