lens for medium size fish portrait?

I recently sign project for fish identification book, so looking for lens for this purpose.

Currently I'm looking for Sigma 17-70mm but I'm not sure it's right choice.

And If I will go with 17-70mm, better use behind dome or flat port?

I have canon 450d body in s&s housing, flat & dome port, 18-55mm, 60mm, 100mm, tokina 10-17mm FE.

Any advise will be appreciated, Thanks in advance.

Hi Enje,

Your 60mm is a great lens for medium size fish. If that is a little tight you might think about the Tokina 35 macro, for the small fry I like to use the 100mm.

Steve

Steve is right -- the 60mm is a good lens for this purpose. It will depend on how big the critter is, how close you think you can get and how bad the waqter quality is. I've used the 100mm for everything from macro to relatively large fish. It does give you some stand-off distance if the fish is skittish so that is valuable. the only problem is that you have to be farther away so backscatter is a potential problem. The 60mm cuts down the standoff distance and gets you closer to medium sized fish. I just returned from a trip to Boniare where I used the Sigma 17-70 fairly often. If you are planning on doing fish portraits or much macro with it, the flat port is definitely better, IMHO. If you need to make use of the 17mm end, then the dome is a better choice. I have a Seatool housing and they make a "wide" flat port so you can use the full zoom range of the lens -- that worked pretty well for most situations. The added capability to use the zoom to frame the shot a bit better is a bonus, if you can get close to the subject. I was able to do medium-sized fish and even large turtles quite easily with this combination.

Mike

Thanks Steve & MikeO, I will try out my 60mm first. :-)