For macro shots of things like zoos: I would recommend no less than a 105mm Macro lens and a tripod. 105mm mostly because our subjects aren't always right next to the glass. The 105mm vs. 60mm macro lenses mean that you can be further away from the subject in the 105mm to get a 1:1 magnification than a 60mm. Even with my 105 sometimes I can't get close enough to a coral for 1:1 unless I build an enclosure to stick the camera in the tank. They're mighty expensive for true 1:1 macro lenses, but the difference is noticible, though it might not be important to everyone. I would highly recommend the Sigma 105mm F/2.8 1:1 Macro w/ HSM. It's a great lens, super sharp, and I use it on all my macros. It's only $400 new, and I may be selling mine very soon. Another option is to go all out and spend $1000 on a Nikkor 105mm F/2.8 1:1 with VR. Those things are awesome, maybe 1:1 macros can even be handheld at the fastest of shutter speeds I think for reef tanks, maybe 150mm macros might be our best bet. I haven't looked into them much yet though. cheers!