Originally posted by naldopr What camera and lens you use?
I have a K-5 now, but third picture I posted was done with my old K100D (6mp body from 2006).
I use all kinds of lenses and different methods, just whatever I feel like using or have handy at the time. The first two I posted were shot with an old Sears branded 60-300 f4-5.6, I only know that because it was fairly recent and I have been really growing to like that lens. The other two were from a while ago I'm not sure what I used, the one with a bunch of different things in it says 20mm on the EXIF, which could have been my Super Lentar (Tokina) 21mm f3.8. The last one I have no clue since apparently I did a long exposure on the tripod with the SR off and I don't have a focal length to go on.
I've got a Vivitar 2x macro teleconverter that turns my cheap 50mm f1.4 into a 100mm f2.8 macro, that works well. I think a 100mm macro would be a good choice for you, it gives you some decent working distance to reach things in the back of the tank.
I posted this one the other day for someone as an example of what an old K100D can do at 1600 ISO, no flash in this one, just tank lights. Just used a cheap old Russian Industar 50-2 because that was what was on the camera at the time. Not the best shot, but I was giving an example of what you can do if you really push that old body. I didn't even post process it at all, just set the camera to JPG and let it do its thing.
Full Resolution
Just about anything you get will give you decent shots with good light and technique. Having really nice new stuff probably does make it easier though. I like to see what I can get out of cheap thrift store lenses, it is a fun challenge.