Canon has taken a quite conservative approach to evolving their dSLR range, adopting features of other manufacturers such as Live View,  Sensor Dust Reduction, In-Camera RAW development, Art Filters, flip out LCD – all of which were in Olympus dSLRs long before Canon decided they were in fact a good idea.

The precursors to this series were among the first CMOS dSLRs which changed digital photography by bringing in the power of the SLR albeit without dedicated lenses for the 1.6x crop factor, these were:

• Canon D30, a 3mpixel camera introduced in 2000
• Canon D60, a 6.3 mpixel camera introduced in 2002

In March 2003, Canon announced the start of a new series – the 6.3mp 10D – derived from the pro 1D series and with magnesium bodies instead of plastic as with the D30 and D60, and the entry  level xx0D series. The body is redesigned from the D60, and adds 10x playback magnification, orientation sensor, brighter LCD, Kelvin-selectable WB, WB bracketing, improved manufacturing of the D60 sensor increasing ISO to 1600 and 3200 via custom function, autoISO, scene modes, 7 point AF, removal of AF asist lamp and replaced with functionality from the flash, ability to register an AF point, improved AIservo AF, improved metering algorithm, a safety shift Tv/Av option, the new DIGIC image processor, ability to select AdobeRGB or sRGB workspace, +/- 2 steps of adjustment for image parameters, direct print support to Canon printers, FAT32 support allowing CF cards greater than 2Gb, improved shutter release lag, a dedicated flash-off scene mode, 12 menu languages instead of 4, and a smaller battery charger.

Common features of most of these cameras include:

• 1.6x crop factor compared to 35mm full frame cameras
• ability to use Canon EF-S lenses as well as Canon EF lenses
• magnesium alloy design with partial environmental seals in 40D onwards BUT the 60D has reverted to plastic design but you do get a flip out LCD!
• pentaprism optical viewfinder but only shows ~95% of the actual image area.
• a shutter speed range of 30sec to 1/8000th sec (I am not sure why they did not make it 60sec as the longest timed shutter as this would make it much more useful for astrophotography in particular).
• 6 white balance positions plus manual setting plus Kelvin setting
• pop-up flash of GN 13m (ISO 100)
• flash sync 1/250th sec instead of 1/200th as on the xx0D range
• PC sync port on pre-50D only (not present on xx0D range and not on the 60D)
• E-TTLII compatibility EXCEPT the 10D which is only E-TTL
• exposure compensation limited to +/- 2 EV EXCEPT the 60D which at last has a decent range and is +/- 5EV
• 35 area metering EXCEPT the 60D which has 63 areas iFCL
• N3 remote connector instead of the lower end E3 connector
• no infrared remote control on models prior to 60D
• wireless TTL control on 60D only
• 60D also loses prior model functionality of joystick, multi-flash support, details in status LCD, AF microadjust, multiple custom modes, buttons.
• orientation sensor
• the models with Live View, like all dSLRs but unlike mirrorless cameras such as micro four Thirds, have a clunky, cumbersome implementation with very slow AF
• a status LCD information screen at top of camera
• at least two command dials
• 2 or 10sec self timer
• timelapse recording via USB cable, TC-80N3 remote controller and a PC
• USB 2.0 except 10D which only had USB 1.1 and thus much slower image transfers to computer
• histogram on playback – luminance or RGB for models starting at 30D
• none have built-in image stabiliser as do Olympus and Sony cameras, but rely on lenses having optical image stabilisation
• none have lens AF microadjustment to ensure accurate AF calibration except for the 50D
• all weigh about 770g with battery

To make the following table easier to read I have deleted the initial model, the 6.3mp 10D which was introduced in 2003.

Comparison feature sets

Feature	20D	30D	40D	50D	60D
year introduced	Nov 2004	April 2006	Oct 2007	Oct 2008	Nov 2010
megapixels	8.2	8.2	10.1	15.1	17.9
pixel density (MP/cm²)	2.4	2.4	3.1	4.5	5.4
max ISO (in brackets max. boost)	1600 (3200)	1600 (3200)	1600 (3200)	3200 (12800)	3200 (12800)
AF points	9	9	9, all cross	9, all cross	9, all cross
Live view magnified manual focus	No	No	Yes	Yes, CDAF (slow)	Yes, CDAF(slow)
Built-in image stabiliser	No	No	No	No	No
Sensor dust removal system	No	No	Yes	Yes	Yes
Flip out, swivel LCD	No	No	No	No	Yes
LCD resolution	1.8″ 118K	2.5″ 230K	3″ 230K	3″ 920K	3″ 1,040K
Video recording	No	No	No	1080i 20fps, 720p 30fps	1080i 30/25/24fps, 720p 60/50fps
external microphone socket	No	No	No	No	Yes
Burst rate	5.0	5.0/3.0	6.5/3.0	6.3/3.0	5.3
Max. RAW in burst	6	11	12?	9?	16
memory card	CF	CF	CF	CF	SD/SDHC /SDXC
mirror lock up	custom	custom	custom	custom	custom
HDMI out for TV playback	No	No	No	Yes	Yes
GPS	No	No	No	No	No
spot metering	No	Yes 3.5%	Yes 3.8%	Yes 3.8%	Yes
custom functions	18	19	24	25	12
lens AF microadjustment for accurate AF	No	No	No	Yes	No
highlight tone mode	No	No	Yes	3 levels	3 levels?
image parameters	basic	picture styles	picture styles	picture styles	picture styles, ambience color, art filters, in-camera RAW development
Noise reduction options	On/Off	On/Off	On/Off	4 levels	4 levels?
in-camera jpeg lens correction	No	No	No	vignetting profiles	vignetting profiles, distortion and CA correction

Interestingly, with the 60D, Canon has lowered the usual specs of this series to provide differential to their new higher end APS-C series which started with the 7D.

Nevertheless, it does offer a good solution for enthusiasts who might also want to do HD video, although the HD video capabilities and ease of use will not match mirrorless cameras such as the Panasonic GH series. To offset this, the phase contrast AF is much better for AF on fast moving subjects than the AF in current mirrorless cameras.