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Timing & Performance

Although it is faster than the S50, the S70 is not a particularly speedy camera, and can sometimes feel a little sluggish when focusing, and particularly in playback mode (scrolling between images). That said, the focus speed in good light (especially at the wide end of the zoom) is perfectly acceptable - the problem comes in low light and at the telephoto end of the zoom, when hunting is common, and missed focus not exactly rare. Continuous shooting performance is perfectly acceptable for a camera of this class, though once the buffer is full things slow down to a crawl.

Timing Notes

All times calculated as an average of three operations. Unless otherwise stated all timings were made on a 3072 x 2304 Super Fine JPEG image (approx. 4,135 KB per image). The media used for these tests was a 1GB SanDisk Ultra II CompactFlash card.

Action Details
Time, secs
Power: Off to Record   2.9
Power: Off to Play Image displayed 2.2
Power: Record to Off All activity ceased 1.9
Power: Play to Off When buffer is empty, lens already retracted ~0.5
Record Review Image displayed ~1.6
Mode: Record to Play   ~0.7
Mode: Play to Record Lens already extended ~1.3
Mode: Play to Record Lens not extended ~2.4
Play: Magnify To full magnification (10x) 1.1
Play: Image to Image Time to display each saved image ~0.7
Play: Thumbnail view 3 x 3 thumbnails ~1.0

Action Details
Time, seconds
Zoom from Wide to Tele 28 to 100 mm (3.6 x) 1.8
Half-press Lag (0->S1) Wide angle ~0.6
Half-press Lag (0->S1) Telephoto ~0.9
Half to Full-press Lag (S1->S2) LCD live view 0.1
Half to Full-press Lag (S1->S2) Viewfinder ~0.06
Full-press Lag (0->S2) LCD live view, wide angle 1.0
Off to Shot Taken LCD live view ~3.6
Shot to Shot Flash off 1.9
Shot to Shot Flash on (with red eye reduction off) 2.3

Lag Timing Definitions

Half-press Lag (0->S1)
Many digital camera users prime the AF and AE systems on their camera by half-pressing the shutter release. This is the amount of time between a half-press of the shutter release and the camera indicating an auto focus & auto exposure lock on the LCD monitor / viewfinder (ready to shoot).
 

(Prime AF/AE)
Half to Full-press Lag (S1->S2)
The amount of time it takes from a full depression of the shutter release button (assuming you have already primed the camera with a half-press) to the image being taken.
 

(Take shot, AF/AE primed)
Full-press Lag (0->S2)
The amount of time it takes from a full depression of the shutter release button (without performing a half-press of the shutter release beforehand) to the image being taken. This is more representative of the use of the camera in a spur of the moment 'point and shoot' situation.
 

(Take shot, AF/AE not primed)

Continuous mode

The tables below show 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 1GB Sandisk Ultra II CompactFlash card. Shutter speed was kept above 1/200 sec during these tests.

Continuous drive mode

The S70 has two continuous shooting modes, one (Burst) offers a higher frame rate (we measured it at around 1.6 fps) for a limited number of frames (5-11, depending on the quality/size setting used), the other offers a lower rate (around 1fps), but for up to 18 frames depending on the file size. In the 'normal' burst mode the S70 displays a brief review of each image saved, in the high speed mode the screen stays blank.

Image Type
Mode
Avg. frames
per sec
Frames in a burst *1
After
burst
*2
3072 x 2304 RAW Burst 0.6 fps 5 1 frame every
8-12 secs
3072 x 2304 RAW Burst High 0.7 fps 5 1 frame every
8-12 secs
3072 x 2304 JPEG Super Fine Burst 1.1 fps 12 0.24 fps
3072 x 2304 JPEG Super Fine Burst High 1.7 fps 8 0.24 fps
3072 x 2304 JPEG Fine Burst 1.1 fps 18 0.34 fps
3072 x 2304 JPEG Fine Burst High 1.6 fps 11 0.4 fps
2592 x 1944 JPEG Super Fine Burst 0.9 fps 12 0.26 fps
2592 x 1944 JPEG Super Fine Burst High 1.6 fps 11 0.4 fps 
2048 x 1536 JPEG Super Fine Burst 1.0 fps 18 0.33 fps
2048 x 1536 JPEG Super Fine Burst High 1.7 fps 11 0.36 fps

*1 In a single "burst" (finger held down on shutter release).
*2 Once the buffer is full the S70 continues to take shots as long as the shutter release is held down - this is the average frame rate over 10 shots.

Not a bad performance at all, though we didn't manage at any point to get near Canon's quoted 2 frames per second, even with a very fast card, nor did we manage to shoot more than 11 frames in a single burst at the high setting (we didn't test at lower than 3 megapixels). It is worth noting that Canon's figures are for Large/Fine setting with the LCD monitor turned off (it was on for our test). If you want to take extended sequences you can, but once the buffer is full the frame rate drops to approximately one picture every 3.5 seconds. The only way to get back up to speed is to wait for the buffer to clear, which takes around half a minute. It's nice that you can shoot continuously in RAW mode, though obviously at a much lower frame rate.

File Write / Display and Sizes

Timings shown below are the time taken for the camera to process and "flush" the image out to the storage card, the timer was started as soon as the shutter release was pressed and stopped when the activity indicator went out. This means the timings also include the camera's processing time and as such are more representative of the actual time to "complete the task". The media used for these tests was a 1GB SanDisk Ultra II CompactFlash card.

Image Type
Time to store
(secs)

Time to display
(secs)

File size *1
(approx.)
Images on a *2
1GB Card
3072 x 2304 RAW ~6.1 ~1.7 7,800 KB 137
3072 x 2304 JPEG Super Fine ~4.9 ~1.7 4,135 KB 324
3072 x 2304 JPEG Fine ~3.7 ~1.6 2,400 KB 520
2592 x 1944 JPEG Super Fine ~4.3 ~1.7 2,700 KB 394
2048 x 1536 JPEG Super Fine ~3.4 ~1.6 1,840 KB 611
16000 x 1200 JPEG Super Fine ~2.8 ~1.7 1,135 KB 975

*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 (detail and noise).
*2 Camera estimation.

The S70 buffers well in normal shooting circumstances, allowing you to shoot at intervals of just under two seconds (including focusing) indefinitely. It's also pretty speedy at processing and saving the data coming off the CCD. The S70 doesn't start writing immediately after taking the shot, it takes around 1.6 seconds to process the images before writing. This translates to a write speed of just under 2MB/s - excellent for a camera of this class (and actually a lot faster than the 5MP PowerShot S60). It's a pity the buffering/writing can't keep up with the continuous shooting mode, and that reading the images off the card (in playback mode) is so leisurely.

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