Canon EOS 40D Review: 13. Timings & Sizes: Digital Photography Review

Timings & File Sizes

The EOS 40D's performance was good with no stand-out issues. Power on is virtually instant, and off to shot taken is a bat-of-an-eyelid quarter of a second, record review (the time taken for the camera to display the image after shutter release) was around one second and playback never takes more than a second, and once cached faster than half a second. Continuous shooting was slightly slower than specified and the fastest speeds can only be achieved with shutter speeds of 1/500 sec or faster. A large buffer and good CF throughput speeds mean that the EOS 40D is always ready to take the next shot and enables you to 'pump' the shutter release without being concerned about hold-ups.

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. 3,200 KB per image).

The media used for these tests were:

2 GB SanDisk Extreme IV CF card
2 GB Lexar Pro 133x CF card
16 GB SanDisk Extreme III CF card

Media comparison

Action	Time, secs (2 GB SanDisk)	Time, secs (2 GB Lexar)	Time, secs (16 GB SanDisk)
Power Off to On	<0.1	<0.1	<0.1
Power Off to Shot	0.25	0.25	0.25
Sleep to On	<0.1	<0.1	<0.1
Power On to Off *1	<0.1	<0.1	<0.1
Record Review RAW *2	1.1	1.1	1.1
Record Review JPEG *2	0.9	0.9	0.9
Enter Live View	1.4	1.4	1.4
Exit Live View	<0.2	<0.2	<0.2
Play RAW	0.5 / 0.3	0.5 / 0.3	0.5 / 0.3
Play JPEG	1.1 / 0.5	1.1 / 0.5	1.1 / 0.5
Play Image to Image RAW	<0.1	<0.1	<0.1
Play Image to Image JPEG	0.8	0.8	0.8

*1	If the camera decides that an automatic 'sensor cleaning' is required then power-off take around 1.5 seconds.
*2	Time taken from the shutter release being pressed to the review image being displayed on the LCD monitor.

Continuous Drive mode

Frame rate vs. shutter speed

Our normal continuous shooting test shutter speed is around 1/500 sec, this normally avoids any slow-down due to the shutter mechanism. However we soon discovered that this wasn't fast enough to achieve the 40D's maximum rate. To achieve maximum shooting rate you need to be at 1/4000 sec or faster (which is a bit disappointing) and will then get 6.3 frames per second at the best (not the specified 6.5 fps). The graph below shows the relationship between shutter speed and frame rate on the EOS 40D.

Continuous drive tests

To test continuous drive mode the camera had the following settings: Manual Focus, ISO 100, Shutter Priority (1/4000 sec). Measurements were taken from audio recordings of the tests. Media used were the same as above.

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

Frame rate - Initial frame rate, this was always 6.3 fps (+/- 0.01 fps)
Number of frames - Number of frames in a burst (until buffer full)
Buffer full rate - Frame rate if shutter release held down after burst (buffer full)
Next burst - How soon after the burst the buffer has emptied / CF compartment light goes out

Burst of JPEG Large/Fine images

Timing	2 GB SanDisk Extreme IV CF	2 GB Lexar Pro 133x CF	16 GB SanDisk Extreme III CF
Frame rate	6.3 fps	6.3 fps	6.3 fps
Number of frames	128	128	98
Buffer full rate	3.0 fps	3.0 fps	1.5 fps
Next burst (buffer 75 indicated)	20.7 sec	20.4 sec	45.1 sec

Burst of RAW images

Timing	2 GB SanDisk Extreme IV CF	2 GB Lexar Pro 133x CF	16 GB SanDisk Extreme III CF
Frame rate	6.3 fps	6.3 fps	6.3 fps
Number of frames	19	19	19
Buffer full rate	1.0 fps	1.0 fps	0.7 fps
Next burst (buffer 17 indicated)	16.2 sec	16.5 sec	22.8 sec

First of all it's probably worth mentioning that we couldn't achieve Canon's advertised 6.5 frames per second, despite testing the fastest shutter speed and various combinations of settings. The other thing to consider is that you can only achieve the fastest frame rates (6.0 fps and faster) from 1/500 sec upwards (I do think Canon should report that caveat in their specifications for the camera). With that said the 40D's performance is still impressive enough, a big buffer means that with the fastest card you can shoot for twenty seconds at full speed before the camera slows to a still pretty acceptable three frames per second.

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 lamp beside the compartment door went out. Media used were the same as above.

Image type	Time, secs (2 GB SanDisk)	Time, secs (2 GB Lexar)	Time, secs (16 GB SanDisk)	Approx. size
3888 x 2592 RAW + JPEG	2.0	2.1	2.6	14,800 KB *1
3888 x 2592 RAW	1.6	1.7	2.0	11,600 KB
3888 x 2592 JPEG Fine	0.9	1.0	1.3	3,200 KB
3888 x 2592 JPEG Std	0.7	0.8	1.1	1,400 KB

*1	File size reported here is the size of the RAW and Fine quality JPEG files added together.

As we should expect the EOS 40D delivers very fast throughput, with the best performing card (the SanDisk Extreme IV) we get over 7 MB/sec for both RAW and RAW+JPEG formats. This combined with a large buffer means that you'll almost never find yourself waiting for images to write to the card (unless perhaps you shoot a burst of RAW+JPEG, pretty unlikely).

USB transfer speed

To test the EOS 40D's USB transfer speed we transferred approximately 128 MB of images (mixed RAW and JPEG) from a SanDisk Extreme IV 2 GB CF card.

Method	Transfer rate
Canon EOS 40D (PTP device)	7.5 MB/sec
CardBus PCMCIA adapter	10.5 MB/sec
SanDisk Extreme IV USB 2.0 card reader	13.3 MB/sec

The EOS 40D just like the EOS 30D doesn't have a 'mass storage device' option, instead communication is carried out using PTP (via WIA on Windows), that said transfer rates are much better than we have seen before via PTP, up to 7.5 MB/sec (more than twice the EOS 30D). That said if you want real performance then just pick up a fairly inexpensive USB 2.0 card reader.

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