Timings & File Sizes

While the Powershot A70's startup time is faster than some of the competition it is crippled slightly by the 0.7 'hold' you must make on the power button before the power up sequence starts, if we include this time total startup is identical to the Coolpix 3100. That said the A70's off to shot taken is quite quick as are shot to shot times. Auto focus speed was slightly above average for this level of camera, and just slightly better if you disable AiAF focus (which leaves you with just the center AF point). Playback is noticeably slower than some others because the camera doesn't display anything until it has loaded the full image from the CF card, perhaps it's time Canon employed the use of a lower resolution thumbnail in the image header to speed up playback.

Timing Notes: All times calculated as an average of three operations. Unless otherwise stated all timings were made on a 2048 x 1536 Super-Fine JPEG image (approx. 1,400 KB per image). The media used for these tests was a 256 MB SanDisk Ultra CF card.

Action	Details	Time, seconds
Power: Off to Record *1	Lens extension	2.7
Power: Off to Play *1	Image displayed	1.8
Power: Record to Off	Lens extended	2.3
Power: Play to Off	Lens already retracted	0.7
Mode: Record to Play *2	Image displayed	2.2
Mode: Play to Record		2.2
Play: Magnify	To 10x magnification	1.0
Play: Thumbnail view	3x3 index, 9 images	1.0

Action	Details	Time, seconds
Zoom from Wide to Tele	Full zoom from 35 mm to 105 mm (3 x)	1.6
Auto Focus LAG	Wide angle	0.8 - 1.0
Auto Focus LAG	Telephoto	1.2 - 1.8
Auto Focus LAG	Wide angle, AiAF On	0.9 - 1.0
Auto Focus LAG	Telephoto, AiAF On	1.5 - 1.8
Shutter Release LAG	Using Viewfinder	<0.1
Shutter Release LAG	Using LCD Monitor	0.1
Total LAG	Wide angle	0.9
Total LAG	Telephoto	1.3
Off to Shot Taken	Wide angle (includes 0.7 power button delay)	3.5
Shot to Shot	Wide angle	1.7

Auto Focus LAG is (roughly) the amount of time it takes the camera to autofocus (a half-press and hold of the shutter release button), this timing is normally the most variable as its affected by the subject matter, current focus position, still or moving subject etc. This timing is an average.

Shutter Release LAG is the amount of time it takes to take the shot from the moment you fully depress the shutter release button, measured both as a time including auto focus and a time assuming you have already pre-focused by holding a half-press of the shutter release.

Continuous mode

The table below shows the results of our continuous shooting test, indicating the actual frame rate along with maximum number of frames and how long you would have to wait after taking the maximum number of frames before you could take another shot. The media used for these tests was a 256 MB SanDisk Ultra CF card.

This performance is highly favourable especially considering the A70's price, in the normal '2048 x 1536 Fine JPEG' mode the camera manages a fairly impressive 1.88 frames per second up to 12 frames. At 1600 x 1200 there's obviously a processing hit involved, hence the slower fps time, at 1024 x 768 (exactly half resolution) performance jumps back up again to 2.02 frames per second. Overall an excellent performance for this level of camera.

File Write / Display and Sizes

Timings shown below are the time taken for the camera to process and "flush" the image out to the CF card, the timer was started as soon as the shutter release was pressed and stopped when activity indicator LED beside the viewfinder stopped blinking. This means the timings also include the cameras processing time and as such are more representative of the actual time to "complete the task". The media used for these tests was a 256 MB SanDisk Ultra CF card.

Above average write speed for this level of camera, the time taken doesn't affect the next shot as writing continues in the background and the A70 has a good sized buffer.

Low Light Auto Focus

This test is designed to measure the minimum amount of light under which the camera can still focus. The focus target is our lens distortion test chart (shown here on the right), camera is positioned exactly 2 m (6.6 ft) away.

Light levels are gradually dropped until the camera can no longer focus. This is carried out at both wide angle and telephoto zoom positions (as more light reaches the focusing systems with a larger aperture).

This test target is the optimum type of subject for most "contrast detect" AF systems (as it has a vertical line at its center), you should consider the results below the best you could expect to achieve.

Light intensity (Lux) = 2.5 x 2^EV (@ ISO 100), 10.76391 Lux = 1 foot-candle (fc)

The A70's rather weak 'orange bulb' AF assist lamp casts a very diffused light without very much range. This is reflected in low light AF performance which should have at least managed to focus at wide angle in complete darkness but instead required at least a dim ambient light to achieve AF lock. There are AF assist lamps and there are AF assist lamps, this is not the best.

Battery life

We ran the camera through our new battery life test. This test is designed to be fair and comparative to each camera and battery type:

• Take 4 shots without flash
• Wait 2 minutes (50% of the time powering the camera off)
• Take 1 shot with flash
• Wait 1 minute
• Repeat

Batteries are fully discharged and recharged before the test and all cameras were reset to their factory default settings. Here are the results:

Easily the most exhausting battery test we've carried out to date, the A70 kept going for just over five hours, and although not shown on this chart that's half an hour longer than its long lasting bigger brother the G5. A truly impressive performance on a set of four (moderate capacity) AA NiMH batteries. Kudos Canon.