Nice backup camera when SLR is too bulky to use

I bought this Canon A630 to back up my Canon Rebel XT dSLR - both are 8 Mpixel. The A630 was intended for situations that didn't require the dSLR attributes - low light, lens interchangeability, bulkiness,and most importantly: the rapid shot-to-shot capability.

The Canon A630 is an excellent point-and-show. The image quality is nearly identical to my Rebel XT (except for low light situations and flash recovery speed).

I had to keep reminding myself this is NOT a Rebel XT (in size, speed, price, bulk, and low light situations). It is a $299 vs. $899 list camera for TOTALLY different purposes.

The swiveling lens is great for off-angle shots (e.g. over head, around corner in tight situation like an aircraft carrier deck, etc.). The 4X zoom is nice; I like 12X, but 4X is perfect for most folks.

The movie mode (640x480 at 30 fps) is very nice too - it still have some artifacts compared to a true video camera, but adequate quality for short clips. I used it for New Year's fireworks in Oahu, Hawaii and the video is pretty good with some artifacts in the dark sky areas. It beats having to carry two cameras.

The menus are very handy - selecting BW or Sepia instantly changes the view finder to show exactly how it looks.

Use of anything beyond ISO 80 is recommended only as last resort. The image noise levels are noticeable and at 400 and beyond, I consider it very bad. If you need the shot, use it, but don't expect good image quality.

I also bought the DC8 underwater housing for snorkeling in Oahu's Hanauma Bay - it allows total control of the camera from power on to ALL features and modes. The pictures I took were fantastic. It would be nice to get an underwater housing for the Rebel XT, but at $900 vs. $199 for the DC8 housing, the A630/DC8 combination is an excellent value with great underwater capability. The flash seemed to work very well underwater (unlike my Pentax Optio s4i - too much debris reflected back into the lens assembly with weird flares). The A630/DC8 underwater performance was beyond my expectations.

Make sure to switch to 'fish' mode to compensate for blueness of underwater.

The 4xAA battery capability is compatible with my battery stash. The SD cards need to be selected carefully. An 8 Mpixel camera can comfortably use a 2GB SD card. However, if you get a 4 or 8 GB card, you MUST get an SD HC-compliant card - the non-SD HC cards do NOT work. I bought/returned a Pretec 4 GB SD card - it was not SD HC-compliant and simply did not work. Canon's website says the A630/A640 are SD HC-compliant and the cards are available, but rather expensive. I made do with 2x2GB cards, but that may be a limitation underwater (as you can't easily change cards on the beach without getting sand/water in the camera). My snorkel outing did just fine with 2 GB card for 2 hours of snorkeling.

Highly recommended. If you like to crop your pictures, I assume the A640 (10 Mpixel) may be better, but the street price is about $100 more. It isn't worth it if you simply 'point-and-shoot' with zero post-processing.