Performance

Overall Performance

The Canon EOS 5D Mark III is powered by the new Digic 5+ processor and it shows in every area. The camera's response to user input, whether via buttons or one of the menus, is as good as instant. Image browsing, magnification and comparison in playback mode is very swift as well.

The Digic 5+ combined with the sensor's 8-channel data-readout also does a good job at pushing the camera's huge 22MP image files through the imaging pipelines and buffer. Despite combined JPEG and Raw file sizes of over 30MB, with a fast CF card the camera can sustain its very respectable 6 frames per second continuous shooting speed for approximately 7 frames. If you limit yourself to shooting JPEGs you really don't need to worry about burst sizes and buffers at all.

The new 61-point AF system offers a much higher level of sophistication and customization than the 5D Mark II's. It works reliably in single AF mode, even in low light levels, and we found it to be performing well when tracking moving subjects in AI Servo mode. There are plenty of customization options and with the right technique sports and action photographers will be able to get consistently good results with the Canon's AF system.

Overall the EOS 5D Mark III is snappy and responsive at all times and simply performs impressively. The camera is not specifically targeted at sports and action photographers, but with its highly customizable and responsive AF system and 6 frames per second continuous shooting, it certainly gives you all the tools you need to capture some impressive action shots.

Continuous Shooting and Buffering

In terms of continuous shooting the EOS 5D Mark III is not quite on the same level as dedicated sports and action cameras such as Canon's EOS-1D Mark IV, but nevertheless its 6 frames per second in Continuous Hi mode still make it a capable tool for shooting fast moving subjects. It's also quicker than the Mark III's closest competitor, the Nikon D800 (4 fps / 5fps in DX mode) or the 5D Mark II (3.9 fps).

With the 5D Mark III's large images files it is advisable to use a fast CF memory card, especially if you are planning to shoot bursts in Raw+JPEG mode. We've noticed that the CF cards slot makes use of the fastest cards that are currently available while this is not the case for the SD-card slot. There was no difference in performance between SD-cards with 45mb/s and 95mb/s transfer rates. That said, when shooting JPEGs only you don't need to worry about the number of frames in a burst, no matter what card you are using. If you need to shoot continuously for sustained periods of time and can make do with a slower frame rate you can switch to the Continuous Lo mode. It offers a speed of 3 frames per second and, with a fast card, you can shoot at that speed until you run out of storage space on the memory card.

Continuous Hi - CF Card

Timing
JPEG Large/Fine
RAW
RAW+JPEG Fine
Frame rate 6.0 fps 6.0 fps 6.0 fps
Number of frames until card full 17 7
Buffer full rate n/a 2.7 2.0
Write complete n/a 4 sec 4 sec

Continuous Hi - SD Card

Timing
JPEG Large/Fine
RAW
RAW+JPEG Fine
Frame rate 6.0 fps 6.0 fps 6.0 fps
Number of frames 42 14 7
Buffer full rate 2.6 0.7 0.5
Write complete 11 17 12

Continuous Lo - CF Card

Timing
JPEG Large/Fine
RAW
RAW+JPEG Fine
Frame rate 3.0 fps 3.0 fps 3.0 fps
Number of frames until card full 23 16
Buffer full rate n/a 2.5 2.0
Write complete n/a 3 sec 3 sec

Continuous Lo - SD Card

Timing
JPEG Large/Fine
RAW
RAW+JPEG Fine
Frame rate 3.0 fps 3.0 fps 3.0 fps
Number of frames until card full 16 8
Buffer full rate n/a 0.7 0.6
Write complete n/a 17 sec 12 sec

All timings performed using a 64GB SanDisk Extreme Pro UHS-I SDHC card (90MB/s) and a 128GB SanDisk Extreme Pro UDMA 7 CF card (100MB/s).

The 5D Mark III's silent shooting mode is available, as 'Continuous S', in continuous shooting. This mode reduces shutter noise and vibration by slowing down the shutter and mirror reflex action. The shutter is noticeably quieter which makes this mode very suitable for noise-sensitive occasions and events, but the continuous shooting performance is the same as in 'Continuous Lo' mode. On the downside there is a slight increase in shutter lag and viewfinder blackout time. We've had a closer look at Silent Shooting on the Features page of this review.

Battery life

The EOS 5D Mark III comes with the same LP-E6 lithium-ion battery pack that was used in the predecessor It's got a capacity of 1800 mAh which, according to Canon, is good for 950 shots (CIPA standard) or approximately 1 hour and 30 minutes of movie shooting time. While shooting our sample images for this review we found the battery life to be approximately in line with Canon's figures and, when leaving the office with a fully-charged battery, never had to worry about running out of power. Of course battery life will to a large degree depend on your shooting conditions and operational habits but for those who prefer to have some backup-power the optional BG-E11 battery grip might be worth an additional investment.