Timing & Performance
Like all recent DIGIC II or III IXUS/SD models the SD900 feels very responsive indeed, and in most respects performance is almost identical to the other models in the range, though the larger 10MP files mean playback is fractionally slower (not that you'd notice). Focus speed in good light is excellent, though it inevitably slows slightly in duller conditions, macro mode and at the long end of the zoom. Shutter lag is - as we've seen with most recent SD models - better if you use the viewfinder (there is video lag when using the screen), but for most purposes it's not an important difference.
All times calculated as an average of three operations. Unless otherwise stated all timings were made on a 3648 x 2376 Fine JPEG image (approx. 4,750 KB per image). The media used for these tests was a 1.0 GB Sandisk Extreme III card.
|Power: Off to Record||0.9|
|Power: Off to Play||Image displayed||1.1|
|Power: Record to Off||All activity ceased||1.5|
|Power: Play to Off||When buffer is empty, lens retracted||~0.2|
|Record Review||Image displayed||~0.9|
|Mode: Play to Record||1.6|
|Mode: Record to Play||With lens retracted||1.8|
|Play: Magnify||To full magnification (10x)||0.9|
|Play: Image to Image||Time to display each saved image||0.4 *1|
|Play: Thumbnail view||3 x 3 thumbnails||~0.6|
|Zoom from Wide to Tele||37 to 111 mm (3x)||1.3|
|Half-press Lag (Focus time)||Wide angle||~0.4 *2|
|Half-press Lag (Focus time)||Telephoto||~0.5 *2|
|Pre-focus Lag (S1>S2)||LCD live view||~0.08|
|Pre-focus Lag (S1>S2)||Viewfinder||~0.05|
|Full-press Lag (0->S2)||LCD live view, wide angle||~0.6|
|Off to Shot Taken||LCD live view||~2.2|
|Shot to Shot||Flash off||~ 2.1|
|Shot to Shot||Flash on ( red eye reduction on / off)||3.5 / 3.8 *3|
|*1||With transition effects turned off - these increase the time marginally.|
|*2||AiAF mode (and especially Face Detect AF) is marginally slower than center focus.|
|*3||Flash recycle time will vary widely according to shooting distance|
Continuous drive mode
Like most SD/IXUS series cameras the SD900 has a single continuous shooting mode, in this case offering around 0.9 frames per second at all file size / quality settings - slower than some SD models, but enough for most typical users. You can't see a preview when shooting bursts, but there is a brief review image displayed after each exposure. Those who like to shoot long sequences will be pleased to hear that there appears to be no limit to how many pictures you can take in a single burst with a fast card. Incidentally you can - unusually - use the flash in continuous mode, at a maximum of around 0.5 frames per second (actual speed will depend on the shooting distance and how freshly charged the battery is).
File writing / playback performance
The SD900 takes around 1.7 seconds to process and save a 4.7MB 10MP/Super Fine JPEG; not bad going at all for a camera of this type - the SD900 will certainly benefit from using faster cards. Playback is also very speedy, with full size images taking under half a second to display (if you use the fancy transition options it takes a little longer to scroll through images, but it sure looks nice). If you want to whiz through hundreds of saved shots you can hold down the left or right arrow key and the SD800 will scroll through low res previews of the images on your card at about 10 per second.
Battery life, like most models in the SD range, is nothing special, though at approx 230 shots (CIPA standard) per charge it's no worse than many of its competitors. As the majority of the power is drawn by that nice big screen, if you switch it off and use the optical viewfinder you can extend the battery life to as much as 700 shots per charge.