Timing & Performance
Like most Canon compacts, the A720 IS is reasonably rapid. It's not going to challenge any DSLRs in any of the timing tests but it's prompt at waking up, switching modes and the crucial things such as focusing speed. Many of the A720 IS's timings are identical to its cousin the IXUS SD870 IS, which you might expect, as they share sensors and processors. The A720 IS only really starts to lose out when functions require the lens to be zoomed (start-up and zooming), because it has a larger, longer lens that takes a bit more time to shunt about.
It's no speed demon and you'd need a lot of luck to capture great images in fast-moving situations, but as compacts go, it's perfectly acceptable. There is lag but it's mainly caused by focusing speed, rather than any major processing delay between the shutter being pressed and the camera responding.
All times calculated as an average of three operations. Unless otherwise stated all timings were made on a 3264 x 2448 Fine JPEG image (approx. 4,000 KB per image). The media used for these tests was a 1.0 GB Sandisk Extreme III card.
|Power: Off to Record||With startup animation disabled||1.3|
|Power: Off to Play||Image displayed||0.9|
|Power: Record to Off||All activity ceased||2.1 *1|
|Power: Play to Off||When buffer is empty, lens retracted||0.2|
|Power: Play to Off||When buffer is empty, lens extended||1.4|
|Record Review||Image displayed||0.9|
|Mode: Play to Record||(Lens already extended)||1.1|
|Play: Magnify||To full magnification (10x)||0.9|
|Play: Image to Image||Time to display each saved image||0.3 *2|
|Play: Thumbnail view||3 x 3 thumbnails||0.6|
|Zoom from Wide to Tele||35 to 210 mm (6 x)||1.9|
|Half-press Lag (Focus time)||Wide angle||~0.6|
|Half-press Lag (Focus time)||Telephoto||~0.6|
|Pre-focus Lag (S1>S2)||LCD live view||~0.1 *3|
|Full-press Lag (0->S2)||LCD live view, wide angle||~0.5|
|Off to Shot Taken||LCD live view||1.8|
|Shot to Shot||Flash off||1.7|
|Shot to Shot||Flash on ( red eye reduction on / off)||2.6 / 3.5 *4|
|*1||Camera takes a further 1.4 seconds to power down if the lens is zoomed to its full extent.|
|*2||With transition effects turned off - these increase the time|
|*3||Actual shutter lag appears to make up around 0.04 of this delay, with LCD lag making up the rest|
|*4||Flash recycle time will vary widely according to shooting distance and battery condition - at the long end of the zoom it can reach 7 or 8 seconds.|
Continuous drive mode
THe A720 IS has Canon's familiar 'pedestrian but unlimited' continuous shooting mode. The larger sensor with the additional data it generates means that the continuous shooting rate is actually slower than on the preceding model. So you get 1.3 frames per second until the battery runs out, the card fills, the light fails, your finger cramps-up or the world ends - whichever happens first.
Although it's unlikely that many users of a camera such as this will need to shoot such long sequences, it's nice to know you can if you want to. There are competing cameras that will shoot faster, but only for short bursts, so if this is a feature you feel you need, then it's worth having a think about whether it's speed or longevity of shooting that you're after.
File writing / playback performance
The A720 IS takes around 1.1 seconds to process and save a ~4.0MB 8MP/Super Fine JPEG (exact size depends on the complexity of the image being shot); which is pretty swift. Given this relatively fast performance, it makes sense to use a fast card to prevent adding a bottleneck to the process. Playback is also very speedy, with full size images taking under a third of 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). Like many Canons, you can scroll through low-res previews of your images (at about 10 frames per second), if you want to rush back and show someone a shot you took earlier.
The A720 IS runs on two AA batteries, which as usual brings benefits (universal availability) and problems (limited capacity and slower than usual flash recycling) in almost equal measure. CIPA standard testing suggests you can expect to get around 140 shots out of the camera with Alkaline batteries or 400 with NiMh rechargeables. You should be able to more than double these figures if you keep the LCD turned off but we don't seriously recommend this as a course of action unless you are hundreds of miles from the nearest supplier of batteries.