Canon PowerShot A70 Review
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.
|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|
|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|
|Off to Shot Taken||Wide angle (includes 0.7 power button delay)||3.5|
|Shot to Shot||Wide angle||1.7|
|*1||You need to hold the power button for 0.7 seconds before the camera starts to power up. This is to avoid accidental knocks of the power button. The timing shown for this measurement exclude this 0.7 seconds.|
|*2||The A70 appears to buffer an image once displayed in play mode. This means that if you return to play mode for a second time the display time is just half a second, compared to two seconds for the first display of a new image.|
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.
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.
|Image Type||Frames per sec||Max no. of frames *1||
|2048 x 1536 Super-Fine JPEG||1.87 fps||7||1.4 secs|
|2048 x 1536 Fine JPEG||1.88 fps||12||1.6 secs|
|1600 x 1200 Fine JPEG||1.68 fps||19||1.2 secs|
|1024 x 768 Fine JPEG||2.02 fps||42||1.0 secs|
|*1||In a single "burst" (finger held down on shutter release)|
|*2||You can take a frame as soon as there is space in the cameras internal buffer (writing continues "in the background").|
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.
on a *2
256 MB CF
|2048 x 1536 Super-Fine JPEG||2.8||1.4||1,400 KB||154|
|2048 x 1536 Fine JPEG||2.4||1.1||850 KB||276|
|1600 x 1200 Fine JPEG||2.2||0.8||530 KB||440|
|1024 x 768 Fine JPEG||2.0||0.6||250 KB||762|
|*1||All file sizes are an average of three files. As is the case with JPEG it's difficult to predict the size of an image because it will vary a fair amount depending on the content of the image (especially the amount of detail captured). For example, take a photograph of a fairly empty wall and you'll get a small JPEG, take a photograph of a bush with a lot of detail and you'll get a larger image. File sizes here are closer to the later, the larger size of file you should expect.|
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.
|Lens position||Aperture||Lowest light focus|
|Wide angle (35 mm equiv.)||F2.8||1.4 EV (6.6 Lux, 0.61 foot-candle)|
|Telephoto (105 mm equiv.)||F4.8||1.8 EV (8.7 Lux, 0.81 foot-candle)|
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.
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
Batteries are fully discharged and recharged before the test and all cameras were reset to their factory default settings. Here are the results:
Compact / Ultra compact
|Battery||Power||Battery life||Number of shots|
|Kyocera S3||BP-800S||2.1 Wh||54 mins||95|
|Canon PowerShot S300||NB-1L||2.5 Wh||1 hr 26 mins||155|
|Pentax Optio 430||D-LI2||3.3 Wh||1 hr 33 mins||160|
|Olympus C-40Z||2 x AA NiMH 1600 mAh (GP)||3.6 Wh||1 hr 33 mins||165|
|Nikon Coolpix 3100||2 x AA NiMH 1600 mAh (GP)||3.6 Wh||1 hr 42 mins||175|
|Minolta DiMAGE F100||2 x AA NiMH 1600 mAh (GP)||3.3 Wh||1 hr 42 mins||175|
|Minolta DiMAGE X||NP-200||2.8 Wh||1 hr 45 mins||180|
|Pentax Optio 330||D-LI2||3.3 Wh||1 hr 48 mins||185|
|Canon PowerShot S330||NB-1LH||2.5 Wh||1 hr 48 mins||185|
|Sony DSC-P71||2 x AA NiMH 1600 mAh (GP)||3.6 Wh||1 hr 50 mins||185|
|Kodak DX4900||2 x AA NiMH 1600 mAh (GP)||3.5 Wh||1 hr 51 mins||190|
|Sony DSC-P5||NP-FC10||2.4 Wh||1 hr 51 mins||190|
|Nikon Coolpix 3500||EN-EL2||4.1 Wh||1 hr 54 mins||195|
|Sony DSC-P9||NP-FC10||2.4 Wh||1 hr 59 mins||200|
|Nikon Coolpix SQ||EN-EL2||3.7 Wh||2 hr 03 mins||210|
|Minolta DiMAGE Xt||NP-200||2.8 Wh||2 hr 12 mins||225|
|Canon PowerShot S400||NP-1LH||2.5 Wh||2 hr 17 mins||230|
|HP Photosmart 812||2 x AA NiMH 1600 mAh (GP)||3.6 Wh||2 hr 21 mins||240|
|Nikon Coolpix 885||EN-EL1||4.8 Wh||2 hr 21 mins||240|
|Nikon Coolpix 775||EN-EL1||4.8 Wh||2 hr 27 mins||250|
|Canon PowerShot SD100||NB-3L||2.9 Wh||2 hr 29 mins||250|
|Pentax Optio S||D-LI8||2.6 Wh||2 hr 33 mins||260|
|Nikon Coolpix 2500||EN-EL2||4.1 Wh||2 hr 33 mins||260|
|Fujifilm FinePix F601Z||NP-60||3.7 Wh||2 hr 47 mins||275|
|Casio EXILIM EX-Z3||NP-20||2.5 Wh||2 hr 48 mins||285|
|Casio EXILIM EX-S3||NP-20||2.5 Wh||2 hr 48 mins||285|
|Olympus C-50Z||LI-10B||4.0 Wh||2 hr 54 mins||295|
|HP Photosmart 935||2 x AA NiMH 1600 mAh (GP)||3.6 Wh||3 hr 09 mins||320|
|Canon PowerShot A70||4 x AA NiMH 1600 mAh (GP)||7.7 Wh||5 hr 08 mins||515|
|Other test notes:|
| LCD monitor is left on during
the battery test
The camera is powered off half of the time and left on half of the time (switch every 10 iterations)
There are now higher capacity AA NiMH batteries available, however in the interests of fair
comparison we will continue to use our 1600 mAh test set
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.
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