Timings & File Sizes

The overall performance of the EOS 400D was good although not perhaps as 'snappy' in-use as its major competitor, the Nikon D80. Startup 'off to shot' time is as good as instant, which means assuming you are sure of camera settings you can flick the power switch and take a shot (auto focus willing) within a few tenths of a second. However the use of the LCD monitor for status display means if you wish to check your settings before shooting (as most of us do) you will have to wait just over one second. Record review was approximately the same as the EOS 350D and Nikon D80, as was play display (Canon's caching working slightly better than Nikon here).

Continuous shooting was a mixed bag, as good as specified but with strange sporadic bursts rather than simply a slower rate, once the buffer was full. Compact Flash write times were also good, and thanks to smart buffering would never really cause any 'real life' delay. One curiosity we observed here were the larger RAW files when shooting RAW+JPEG compared to RAW. Lastly I was disappointed Canon still haven't implemented a mass storage device driver in the camera, you are stuck with WIA which doesn't provide for transfer of RAW files.

Timing Notes: All times calculated as an average of three operations. Unless otherwise stated all timings were made on a 3888 x 2592 JPEG Fine (approx. 3,100 KB per image).

The media used for these tests were:

• 2 GB SanDisk Extreme IV CF card
• 2 GB Lexar Pro 133x CF card
• 8 GB Lexar Pro 133x CF card

Continuous Drive mode

To test continuous mode the camera had the following settings: Manual Focus, Manual Exposure (1/200 sec, F5.6), ISO 200. Measurements were taken from audio recordings of the tests. Media used were the same as above.

Sporadic 'buffer full' bursts

When shooting continuously the camera is writing images to its buffer and these are being processed and written out to the storage card 'in the background'. Typically once the buffer is full the continuous shooting rate simply slows to the speed at which the camera can remove an image from the buffer and make space for another (hence the storage card write speed), this normally equates to a frame a second. The EOS 400D demonstrates a quite different behaviour, which is far more difficult to predict.

Once the EOS 400D's buffer is full it simply pauses, for a few seconds, and then fires off another burst of shots (or just one) and then pauses again. This sporadic 'buffer full' continuous shooting is best demonstrated by waveforms of audio recordings (shown below).

JPEG Large/Fine - 31 images in the intial burst, then a pause of 5.6 seconds, then burst of nine shots shortly followed by another five (and so on).
RAW - 11 images in the intial burst, then a pause of 3.6 seconds, then one shot, then a pause of 2.5 seconds, then two more shots (and so on).

This sporadic shooting made it a little more difficult to test the EOS 400D, hence we could not measure the 'buffer full rate' or 'next burst' was we normally do.

The tests carried out below measured the following results for JPEG and RAW:

• Frame rate - Initial frame rate, this was always 3.0 fps (+/- 0.05 fps)
• Number of frames - Number of frames in a burst
• Write complete - How long after the last shot before the CF lamp goes out

Burst of JPEG Large/Fine images

Burst of JPEG Large/Standard images

Burst of RAW images

The EOS 400D's actual continuous shooting performance was as specified, three frames per second and bursts greater than the specified minimum (31/11 vs. 27/10; JPEG/RAW). It's what happens once the buffer is full that concerns us. The most graceful way to manage a full buffer is to allow the camera to take one shot each time enough buffer space becomes available (this would be the write time per image), most other digital SLR's handle a 'buffer full' situation in this way (dropping to around one frame per second). The EOS 400D's sporadic 'buffer full' burst-type shooting was confusing and difficult to predict and could lead to some odd results in a real life situation.

File Flush Timing

Timings shown below are the time taken for the camera to process and "flush" the image out to the storage card. Timing was taken from the instant the shutter release was pressed to the time the storage card activity indicator lamp went out. The activity indicator light comes almost as soon as you press the shutter release, this either means that the EOS 400D begins writing immediately or that Canon is masking the delay to write. Writing continues 'in the background' and doesn't affect any camera function. Media used were the same as above.

Single shot write times are fast enough to be unnoticeable, especially considering the background processing and buffering. As noted above we found the .CR2 files created in RAW+JPEG mode to be around 3 MB larger than in just RAW mode, indicating that perhaps Canon are also embedding the full quality, full resolution Large/Fine JPEG within the .CR2 file in RAW+JPEG mode. The only difference in performance was with the larger FAT32 format card which was slightly slower. Overall write performance was between 4 and 5 MB/sec (although this is difficult to verify because of the way the activity indicator comes on as soon as the shot is taken).

USB transfer speed

To test the EOS 400D's USB speed we transferred approximately 200 MB of images (mixed RAW and JPEG) from a SanDisk Extreme IV 2 GB CF card (the same card used in the other readers). With the 400D connected the only transfer method available is WIA, Canon doesn't provide a simple 'mass storage device' feature in the camera (enabling the camera to act as a normal card reader). Because of this you have to have EOS Utility installed to ensure the transfer of all your images (as drag-and-drop WIA doesn't support RAW), frankly the EOS Utility transfer speed was pretty poor.

Battery life

The EOS 400D uses the same small Lithium-Ion NB-2LH battery as the EOS 350D, this provides 720 mAh at 7.4 V which is around 65% the capacity of the larger BP-511A battery used in the EOS 30D. Quoted CIPA test battery life compared to the EOS 350D is down, but not significantly, this will no doubt be due to the use of the main LCD monitor for status display. We didn't suffer any flat battery situations, however I would recommend carrying a spare battery for all day shoots. Canon report tested battery life as: