Timings & File Sizes

Overall performance of the EOS 300D was as we had expected, slightly slower than the EOS 10D but still with distinctive D-SLR responsiveness, compared to even a high end prosumer digital camera the EOS 300D is fast. Compared to the EOS 10D startup time was 0.7 sec longer and image processing per image was slightly slower. Other measurements such as record review time and CF write speed were virtually identical. Interestingly Canon appeared to have made some improvements, Image to Image times in playback were noticeably quicker than the EOS 10D thanks to a higher resolution embedded JPEG in the file header (no 'rough thumbnail'). This did however appeared to have a negative impact on thumbnail index which was approximately 3.5 times slower. Overall however the differences in performance between the EOS 300D and the EOS 10D (apart from continuous shooting and buffer size) are negligible.

Timing Notes: All times calculated as an average of three operations. Unless otherwise stated all timings were made on a 3072 x 2048 Large / Fine JPEG image (approx. 2.2 MB per image).

The media used for these tests were:

• 256 MB Canon High Speed Type I Compact Flash card
• 512 MB SanDisk Ultra Type I Compact Flash card
• 1 GB IBM Microdrive Type II Compact Flash card

Action	Details	Time, seconds (Canon CF)	Time, seconds (SanDisk CF)	Time, seconds (Microdrive)
Power: Off to On		3.0	3.2	2.9
Power: On to Off *1		<0.1	<0.1	<0.1
Record: Review *2	JPEG	1.8	1.8	2.2
Record: Review *2	RAW	2.5	2.6	2.9
Record: Review (Info) *2	JPEG	1.9	1.9	2.3
Record: Review (Info) *2	RAW	2.5	2.6	3.1
Play: Image to Image *3	JPEG	0.8	0.7	1.7
Play: Image to Image *3	RAW	2.2	1.8	2.3
Play: Thumbnail view 3 x 3	JPEG *4	5.1	4.3	5.5
Play: Thumbnail view 3 x 3	RAW	1.9	1.6	2.5
Play: Magnify to x10		3.5	3.5	3.5

Smart buffering

Smart buffering is something which was first seen on the EOS-D60 and was carried forward with the advent of the EOS 10D. I'm glad to report that it appears as though this method of buffering is also a feature of the EOS 300D, although the EOS 300D has a smaller buffer than the EOS 10D (4 images compared to the 10D's 9 images).

The Smart buffering method improves both single shot and continuous drive shooting. The EOS 300D uses its internal buffer for two purposes: buffer the data as it comes from the image sensor (we will call this unprocessed data) and subsequently buffer converted image files before they are written to the CF card. Note that the camera will not write to the CF card unless it is "idle", this means that if you hold the shutter release button in the half-press position the camera will hold the converted image files in the internal buffer until you release.

Image processing sequence:

1. Record data as it comes off the image sensor, unprocessed data (approx. 9.3 MB per shot)
2. Store this unprocessed data in the SDRAM buffer
3. Take unprocessed data and convert into image files (JPEG or compressed RAW)
4. Buffer these converted image files (JPEG approx. 3.0 MB or RAW approx. 6.0 MB)
5. Write JPEG / RAW image files to CF card

This means that although the buffer can be filled with a continuous burst of four shots it quickly regains buffer space as the unprocessed images are converted into the JPEG or RAW image files. In a real life situation it's easy to believe that the stage 2 runs concurrently to new unprocessed data being buffered.

Take four shots in a continuous burst, keep your finger half-pressed on the shutter release and despite the fact that nothing is being written to the CF card you will see the buffer space indicator fairly quickly count back up again. Remove your finger from the shutter release and the counter doesn't change but you can observe data being written to the CF card (indicator light on the CF compartment door flickers).

Repeating this test for both JPEG Large/Fine and RAW I discovered that the buffer has space (without writing any data to the CF card) for:

• 4 x JPEG Large/Fine images and approx. 2.6 seconds later indicates space to shoot 4 more
• 4 x RAW images and approx. 4.9 seconds later indicates space to shoot 2 more (you must then allow RAW images to be written to CF before any more space is available)

The EOS 300D takes approximately 0.65 sec to convert the unprocessed data into a JPEG Large / Fine file, approximately 2.45 sec to for a compressed RAW file.

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. Before the shutter release is half pressed the lens is manually focused to the closest subject distance (typically 0.5 m) to "throw the focus out". This test target is the optimum type of subject for most AF systems (as it has a vertical line at its center).

Note that the EOS 300D's AF assist works in the same way as the EOS 10D. You must have the pop-up flash raised, it will fire a burst of low power flash strobes which light the subject. If the AF point is near to the last focused distance then the strobe may only flash once, if it is taking longer to get a lock it may strobe several times (up to 10 or 15 times).

In our tests none of the lenses failed to focus with the AF assist and most took no longer than two seconds, the L lens and the 50 mm lens took no longer than 1.2 seconds. Without the AF assist lamp all the lenses focused in very dim light (less than a candle), interestingly all seemed to take 2.6 seconds to go from their nearest focus position to the correct focus distance (the longest amount of time you should expect AF to take). Remember if you focus on something which is a similar distance to the last focus distance AF time is cut dramatically, in some cases taking less than 100 ms.

Overall performance was virtually identical to the EOS 10D (taking test error into account), this is what we would expect as both cameras utilize the same AF sensor. Remember that this test is designed to measure the performance of the AF system in very low light, our experience in good light was that the camera completed AF very quickly and very accurately.

Continuous drive mode

To test continuous mode the camera had the following settings: Manual Focus, Manual Exposure (1/250 sec, F3.5), ISO 400. No matter what image output format the shooting rate is always 2.5 fps (+/- 0.1 fps). With this in mind we decided to test a different set of parameters:

• Next single shot - How soon after a burst of four shots you can take the next single shot
• Next burst of four - How soon after a burst of four shots you can take another four
• Full write - How long a burst of four shots takes to be processed and written to the CF

The media used for these tests were:

• 256 MB Canon High Speed Type I Compact Flash card
• 512 MB SanDisk Ultra Type I Compact Flash card
• 1 GB IBM Microdrive Type II Compact Flash card

Burst of four JPEG images

Burst of four RAW images

Because of its relatively fast processing speed the EOS 300D allows you to take a total of eight 6mp JPEG images in just over 6 seconds (a burst of four, wait 3 seconds, another burst of four). A very respectable performance for an 'entry level' digital SLR and certainly enough to scare off most prosumer level digital cameras.

File Write Timing

Timings shown below are the time taken for the camera to process and "flush" the image out to the storage media. The EOS 300D continues to process images in the buffer and write data out to the storage media in parallel to you composing (and taking) the next shot. It only pauses this writing if you half-press the shutter release.

The media used for these tests were:

• 256 MB Canon High Speed Type I Compact Flash card
• 512 MB SanDisk Ultra Type I Compact Flash card
• 1 GB IBM Microdrive Type II Compact Flash card

Write times are pretty much in line with the EOS 10D which probably means that both cameras have the same CF interface, interestingly however the EOS 300D takes very slightly longer to process the image before it begins writing thus the total time from the moment you press the shutter release to the CF compartment light going out will be very slightly longer.

Odder still is that the EOS 300D's file sizes are identical to the EOS 10D which is strange because Canon's press release for the EOS 300D clearly quotes larger file sizes, perhaps they have had a change of strategy and now quote file sizes for higher ISO sensitivities. (* File sizes should be larger because of the larger embedded thumbnail image)

Here are the approximate write throughput figures for each card:

• 256 MB Canon High Speed: 1.2 MB/sec
• 512 MB SimpleTech: 1.5 MB/sec
• 1 GB IBM Microdrive: 1.3 MB/sec

Battery life

The EOS 300D has the same virtually Canon standard BP-511 Lithium-Ion rechargeable battery. This unit is rated at 7.4V, 1100 mAh (8.1 Wh), it's small and lightweight, charges quickly and lasts very well. Battery life with the EOS 300D appeared to be quite similar to the EOS 10D. We do not currently have facilities to test battery life for digital SLR's but have no reason to doubt Canon's own figures from the user manual.

Canon supplied battery life data