see also:

• Canon EOS camera system
• Canon EOS full frame dSLRs compared
• Canon 5D Mark IV dSLR
• Nikon D750 full frame dSLR
• Nikon D800 dSLR

• announced March 2012, the Mark III represents nearly everything Mark II owners wished their camera had:
  • weatherproofed magnesium body
  • fast AF
  • reasonable burst rates
• very sensibly, Canon decided against following the lead of the Nikon D800's 36mp sensor, and instead opted for what is probably a better compromise - a 22mp sensor with presumably better high ISO performance and better dynamic range
• nevertheless, consumers and pros may still decide the 36mp Nikon D800 is their preferred camera.
• interestingly, Canon also announced their 1st radio remote TTL flash transmitter and new RT flash.
  • this development will add some competition to PocketWizard remote TTL flash devices

• flash sync only 1/200th sec - not great for strobists, fashion photographers or wedding photographers working outdoors
• no AF at f/8 - not great for wildlife photographers wanting to shoot f/4 telephoto lenses with a 2x teleconverter
  • now fixed with firmware 1.2.1 May 2013
• poor image detail in HD video
• not yet compatible with PocketWizard TTL radio remote TTL flash
  • “The 5D Mark III, like the 5D Mark II and 7D before it, is presenting unique reverse engineering challenges.”

• weatherproofed body based on a Canon 7D design
• 22mp full frame sensor with 8-channel sensor readout enables continuous shooting at 6 fps
• supports radio remote TTL flash (need the new Canon 600EX-RT flash and the WT-E3-RT wireless transmitter) which now allows up to 15 flashes in 5 groups
• no built-in flash
• a major disappontment is the reduction of flash sync to only 1/200th sec
• ISO 100-25600 standard, 50-102,800 expanded and autoISO can be given an upper and lower range as well as setting a minimum shutter speed (1/250th - 1 sec only, bad luck if you are a sports photographer who wants 1/500th sec and wants to avoid Shutter Priority metering)
• Shutter rated to 150,000 frames and has range of 30sec -1/8000th sec
• 1D X's “silent” shutter mode, allowing it to shoot in both single images and continuously (at 3fps) with greatly reduced shutter and mirror noise
• 100% viewfinder coverage
• 1040k dot 3:2 fixed LCD but no touch screen as in most Micro Four Thirds system
• Dual card slots for CF and SD supporting SDHC/SDXC and Eye-Fi wireless cards
• 61 point AF system (41 of them are cross-type points and, uniquely to this sensor, 5 of them are diagonally sensitive) and new menu system as in the Canon 1D X sports dSLR but doesn't have the 1D X's 100,000 pixel metering sensor to gain tracking information from, nor a dedicated DIGIC 4 processor to make sense of it all.
  • disappointingly, like the Canon 1D X sports dSLR, the cross-type points can only be used with lenses that are F4 or brighter (and the double-crosses with F2.8 and brighter lenses) and worse, you cannot AF at all using f/8 (ie. when using a 2x converter with an f/4 lens which will disappoint many wildlife photographers)
• 63 zone iFCL metering system
• DIGIC 5+ processor
• in-camera HDR shooting mode and HDR bracketing up to 7 frames covering a +/- 8 EV range
• exposure compensation +/- 5EV
• multiple exposures
• electronic levels display in viewfinder and LCD
• AF Microadjustment now allows programming BOTH ends of a zoom lens range
• automatic vignetting and chromatic aberration correction in jpegs, based on lens profiles which are stored in-camera but obviously only works on Canon lenses and most Canon users would not bother using in-camera jpegs anyway (this in not an Olympus jpeg engine) and would prefer to process RAW files
• USB 2.0
• mini HDMI out but no live video out?
• optional BG-E11 vertical grip with extra battery
• optional GP-E2 unit for GPS
• optional WFT-E7 wireless transmitter unit
• N3 type remote control cable outlet which allows timelapse recording via PC or cabled remote device
• 950g
• 152 x 116 x 76 mm (5.98 x 4.57 x 2.99“)

• 1080 30/25/24p H.264 but in reality, vertical resolution only seems to be 720p
• 720 60/50p
• VGA 30/25 fps
• All-I and IPB interframe compression options:
  • All-I: each frame is treated independently, rather than trying to identify and compress common areas for neighboring frames
  • IPB interframe: 4x file size thus 22minutes will require 64Gb
• moire-correction during recording
• SMPTE timecode recording (Rec-Run and Free-Run)
• less rolling shutter than with the 5D Mark II
• built-in headphone socket for audio monitoring, and rear control dial now has touch-sensitive 'buttons' that allow recording parameters (shutter speed, apertire, ISO and sound volume) to be changed silently
• mono microphone
• the Panasonic GH-2 camera and Nikon D800 dSLR have much better resolution and compression codec than full frame 1080p HD video of the Canon 5D Mark III or the Nikon D4 sports dSLR¹⁾
• for a nice real world comparison of HD video capabilities of D800 vs Canon 5D Mark III, see Dan Chung's review here
• uses Level 5.1 H.264 encoding so to get the best results using Adobe Premiere, change from Adobe's default H.264 Level 4.2 encoder to Level 5.1 which gives far better colour, tonality, contrast, less noise and less macro blocking²⁾
• Firmware version 1.2.1 (May 2013) allows uncompressed 8-bit 4:2:2 video output with time code over the HDMI port. Uncompressed video can be output while the video feed is simultaneously displayed via the rear LCD panel and recorded to the camera's CF/SD cards.

• dpreview.com's preview
• dpreview.com's review
  • great camera but poor jpegs out of camera - “Even at low sensitivities the camera's JPEG engine applies visibly destructive noise reduction which results in mushy low-contrast detail…. and fine-tuning image parameters such as noise reduction or sharpening doesn't help much….the heavy-handed noise reduction leads to lack of low-contrast detail at higher ISOs”
  • soft HD video output
• Dan Chung's review of HD video vs Nikon D800
• EOSHD review of HD video vs Nikon D800
• Ayton blog - new cameras compared – Olympus OM-D E-M5 vs Canon 5D Mark III vs Nikon D800