I have the a620 and canon housing, do you have any experience with the A620? would you think I would experience similiar results? what depth were you at in most of these? your pics are beautiful. I have photography as a hobby. I shoot with all canon gear.. A620 is my PS I also have a canon DSLR and acessories.
I don't have any experience with the 620, but I think it is quite similar to the 630. They are not identical, however; the 610 and 620 are twins (use the same housing, only difference is more mpx in the 620), whereas the 630 and 640 are twins (use the same housing which is different from the 610/620). So Canon did some changes, at least to the body configuration, when they upgraded to the 630. Still, I would think the 620 would produce very similar results to the 630 in terms of quality and resolution. My Culebra pictures were all taken at depths less than 15 ft. I see you are listed as not being certified; are you planning to use the camera for snorkeling? If so, you absolutely have to use a weight belt to get down to where the fish are. Shots from the surface looking down are almost never good. Buoyancy control is virtually impossible when snorkeling, and you also frequently have to deal with surge. I dive down and hold onto a rock (not coral!) with one hand to stead myself, then take the picture with the camera in my other hand.