Canon PowerShot SD450 Digital ELPH / Digital IXUS 55 Review
Timing & Performance
In use the SD450 - like most models in the PowerShot SD range - feels very fast, and very responsive, something our tests bore out. From powering up to zooming to using the menus, taking pictures and using the flash, the SD450 performs brilliantly, rarely - if ever - leaving you waiting. Although Canon still can't match some of its competitors when it comes to focus speed, the SD450 is not bad at all, especially if you turn off the AiAF function. There is very little hunting even at the long end of the zoom in fairly low light (though focus speed does slow down in such conditions). Continuous shooting performance is excellent, as long as you use a fast SD card, and the shutter lag, especially when using the optical viewfinder, feels almost instantaneous.
All times are calculated as an average of three operations. Unless otherwise stated all timings were made on a 2592 x 1944 SuperFine JPEG image (approx. 2,500 KB per image). The media used for these tests was a 1GB SanDisk Extreme III SD card.
|Power: Off to Record||1.2|
|Power: Off to Play||Image displayed||1.1|
|Power: Record to Off||All activity ceased||2.0|
|Power: Play to Off||When buffer is empty||~0.2|
|Record Review||Image displayed||~0.5|
|Mode: Record to Play||1.3|
|Mode: Play to Record||Lens already extended||~1.5|
|Play: Magnify||To full magnification (10x)||~0.9|
|Play: Image to Image||No transition effect||~0.25|
|Play: Image to Image||With transition effect||~0.4|
|Play: Thumbnail view||3 x 3 thumbnails||~0.4|
|Zoom from Wide to Tele||35 to 105 mm (3 x)||1.3|
|Half-press Lag (0->S1)||Wide angle||~0.45|
|Half-press Lag (0->S1)||Telephoto||~0.65|
|Half to Full-press Lag (S1->S2)||LCD live view||~0.06|
|Half to Full-press Lag (S1->S2)||Viewfinder||~0.05|
|Full-press Lag (0->S2)||LCD live view, wide angle||~0.45|
|Off to Shot Taken||LCD live view||~1.8|
|Shot to Shot||Flash off||1.4|
|Shot to Shot||Flash on (red eye reduction off)||2.4|
|Shot to Shot||Flash on (red eye reduction off)||2.9|
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).
|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)
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 Extreme III SD card. Shutter speed was kept above 1/200 sec during these tests.
Continuous drive mode
The SD450 has a single continuous shooting modes, and a brief review image is displayed for each frame captured. We found the frame rate dropped slightly at lower resolutions (something fairly common).
Frames in a burst *1
|2592 x 1944 JPEG Super Fine||Continuous||2.05 fps||Unlimited||n/a|
|2592 x 1944 JPEG Fine||Continuous||2.08 fps||Unlimited||n/a|
|2592 x 1944 JPEG Normal||Continuous||2.05 fps||Unlimited||n/a|
|2048 x 1536 JPEG Super Fine||Continuous||1.9 fps||Unlimited||n/a|
|2048 x 1536 JPEG Fine||Continuous||1.9 fps||Unlimited||n/a|
|1600 x 1200 JPEG Super Fine||Continuous||2.0 fps||Unlimited||n/a|
|1600 x 1200 JPEG Fine||Continuous||2.0 fps||Unlimited||n/a|
|*1||In a single "burst" (finger held down on shutter release).|
|*2||In our extensive tests we could not get to the point - even after 50 or 60 shots - where the buffer caused the frame rate to drop or the shooting to pause significantly.|
Nothing to complain about here; not only does the SD450 manage to maintain a good two frames per second or so at all file sizes and quality settings, the buffering is so fast that you can shoot pretty much indefinitely, even at the top 5MP/Super Fine setting, as long as you have a fast enough SD card. After a burst of 50 or so shots we did measure a slight fall-off in the frame rate from time to time, but to all intents and purposes it is impossible to fill the buffer, meaning you can keep shooting for as long as you have the battery power and card capacity to do so. Interestingly this means that when using the LCD you can hold the shutter down and drain the battery within a few minutes!
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 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 Extreme III SD card.
Time to store
Time to display
File size *1
Images on a *2
|2592 x 1944 JPEG Super Fine||~0.9||~0.25||2,510 KB||391|
|2592 x 1944 JPEG Fine||~0.7||~0.25||1,550 KB||695|
|2592 x 1944 JPEG Normal||~0.6||~0.25||720 KB||1376|
|2048 x 1536 JPEG Super Fine||~0.8||~0.25||1,600 KB||607|
|2048 x 1536 JPEG Fine||~0.6||~0.25||970 KB||1086|
|1600 x 1200 JPEG Super Fine||~0.6||~0.2||1,070 KB||967|
|*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).|
With write times averaging under a second for a 5MP Fine JPEG, the SD450 is pretty fast (2.8MB/s). This is a camera that can make the most of a fast card, unlike most compact and ultra-compact models.
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