The Canon A630 is a great camera but you need to follow some basic steps to get good photos like in any other camera.
First you need to have basic photography knowledge. Depth of field, shooter speed, ISO settings, etc.
Important things before start to take the photos:
* Clean the glass
* Shut off all the pumps to avoid movement
* I have to assume that you have good lighting because low light will make it more difficult
* For full tank pics there is no need for a tripod but will help to use one
* For all macro photos you need to use a tripod
* Use the drive mode with 2-second delay on the shooter. That will minimize movement on shooting
* If you have good light use ISO 80 to avoid noise (distortion)
* Use the largest pic size your camera provides. In the canon use large and superfine.
* Do not use the zoom. Use the widest setting or your will be out of focus. If you want to get close CROP the photo. With 8 mega pixels you will be amazed as to how close you can get cropping!
* Use manual focus for close-ups. You can use auto focus but your camera may get confused in some low light shots.
* Take as many pics as you can. I usually save one out of ten photos. Use a big memory card.
* I use Av (aperture priority) with the largest f setting, which is f8 in the Canon. That way you will have more depth of field. More of the photo will be in focus.
* I only use flash for some fish photos but I don’t like the colors with flash
* Use some software to process the photos. I use HP Photosmart Premium. It was included with my HP computer. It is excellent to crop, resize, and adjust the image for color, brightness, exposure, sharpness, etc.
Practice, practice, more practice and these tips will result in excellent photos..
I hope this helps.