Performance speed

Overall Performance

The Canon EOS 6D is powered by the same Digic 5+ processor found in its full frame stablemates, the EOS 5D Mark III and dual-chipped 1D X, offering extended JPEG processing capabilities such as correction for lens CA and vignetting, as well as raw file processing. And, as we noted in our Canon EOS 5D Mark III review, the 6D is quick to respond to user input whether adjusting shooting parameters or navigating menu operations. Image browsing and magnification in playback mode is very swift as well. The camera can power on and capture a still image in just under 0.4 seconds when set to manual focus. In short, you're unlikely to find yourself waiting on the camera, outside of a very processor intensive operation like the multiple exposure HDR mode.

Canon has, however, made it fairly obvious where they've decided to both keep costs down and avoid trampling interest in the higher spec'd 5D Mark III. The EOS 6D is the only full frame DSLR on the market with just a single storage card slot, accepting an SD card. The camera's AF system is decidedly less sophisticated than the more expensive Canon DSLRS and is limited to 11 autofocus points, less than a third fewer than is found on its direct competitor, the Nikon D600. It also lacks the live view hybrid AF system Canon introduced with their lower-end EOS 650D. Canon has given 6D owners one significant bragging right, though: autofocus sensitivity as low as -3EV, which we'll discuss in a moment.

Continuous Shooting and Buffering

While the EOS 6D is a fast camera to operate, it lists a rather pedestrian maximum frame rate of 4.5 fps, slower than all but the 36MP Nikon D800 in the full frame DSLR market. As with other Canon DSLRs, this maximum frame rate is consistent among the 6D's file format and image quality options. You should know, however, that if you opt for the 6D's impressively effective silent shooting mode, the maximum shooting rate drops to 3 fps. Outside of that, the 6D's performance distinctions revolve around its buffer capacity. Shooting in RAW+JPEG mode for example, provides you with relatively few shots at maximum fps before the camera drops to a pokey 1 fps shooting rate.

When shooting fast action sequences, the great benefit to shooting in JPEG mode is of course that you can shoot uninterrupted bursts in continuous shooting mode. Powered by its DIGIC 5+ processor, the 6D is able to off-load its 20MP files before the buffer fills completely. Regardless of which image quality option you've selected, you can access the menu system and change shooting modes while data is being written to the card.

Continuous mode

In continuous shooting mode, we measured a maximum shooting rate of 4.3 fps, virtually identical to Canon's specs. The 6D maintains its maximum frame rate in raw-enabled modes until it reaches its buffer capacity and must off-load image data to the SD card. When this happens, the camera shoots at a slower but consistent frame rate indicated by the 'buffer full rates' shown in the table below.

Timing
JPEG Large/Fine
RAW
RAW+JPEG Fine
Frame rate 4.3 fps 4.3 fps 4.3 fps
Number of frames Until card is full 15 8
Buffer full rate n/a 1.4 fps 1.1 fps
Write complete n/a 8.4 sec 5.2 sec

In the raw-enabled shooting modes, once the buffer is full you can still fire off images while the data is being written to the SD card. For the majority of the buffering time, however, you're limited to shooting just single images.

All timings performed using a 64GB SanDisk Extreme Pro UHS-I SDHC card (90MB/s).

Autofocus

Autofocus area

At a frame rate just over 4 fps, no one would mistake the EOS 6D for a dedicated sports shooting camera. Even those looking to grab only the occasional action shot, however, are likely be more limited by the camera's relatively small AF coverage area than by its burst rate. As we noted in our Nikon D600 review, part of the price you pay for a more affordable full frame DSLR is a smaller portion of the scene that be covered by the camera's AF points.

And while Nikon at least saw fit to provide dense coverage of the AF area with 39 focus points, Canon EOS 6D users will have to make do with just 11. And only the center AF point is cross-type (with both horizontal and vertical lines detected simultaneously), the remaining 10 being either vertical or horizontal-line sensitive.

Superimposed over this image are the 11-point AF area region for the EOS 6D and the boundary of the larger 61-point counterpart found on the EOS 5D Mark III. The smaller coverage of the 6D is compounded by the inclusion of so few AF points, spaced so far apart.

In the (simulated) example shown here, both players are still largely covered by the wider AF array of the 5D Mark III, while the 6D just barely reach the hip of the player in the white jersey.

AF Performance

Focus acquisition on the EOS 6D displays all the hallmarks of mature phase detection AF performance. The camera is quick to lock focus and under most conditions does so with a high degree of accuracy. In reviewing hundreds of images shot with the 6D, the vast majority of shots that did lack critical sharpness were due to either subject or camera movement. Photographing active children indoors will be a challenge, but you will come away with keepers - if you keep your subjects largely in the middle of the frame.

The area where the 6D really shines, however, is in acquiring focus consistently in very low-light conditions. Canon has rated the center AF point's sensitivity at -3 EV, one stop lower than any full frame DSLR on the market. And our real world use with the camera bears out this impressive performance.

ISO 51,200, F2.0, 1/80 sec.

Although it may look as if it was shot in daylight, this image was captured an hour before sunrise under a heavily overcast sky. The source of ambient light was a street lamp located about 10m behind the Land Rover. The 6D was able to lock focus on the side door logo with only a very slight delay. In this low light, it was only the center AF point that could acquire focus.

While not every 6D owner will find themselves regularly out shooting before dawn, there's no denying the benefits of solid AF performance in low-light indoor scenarios. The photograph below was shot in a dimly-lit lounge and focus was consistently fast and reliable, even using an outer AF point.

ISO 25,600 F4 at 1/125 sec.: This portrait was shot at the tele end of the Canon EF 24-105mm F4L IS USM zoom. Even in this dimly lit area, ambient light was sufficient to acquire focus with the outermost AF point.

The EOS 6D also offers the same AF microadjust as the 5D Mark III. Adjustments can be made separately for the wide and telephoto ends of zoom lenses, and can also be made per serial-numbered lens (should you have two copies of the same lens that require differing amounts of adjustment).

Battery life

The EOS 6D uses the same LP-E6 lithium-ion battery found in the EOS 60D, 7D and 5D Mark III models. It's got a capacity of 1800 mAh which, according to Canon, is good for as many as 1,090 shots (CIPA standard) when shooting through the viewfinder. While shooting our sample images for this review we found the battery life to be approximately in line with Canon's figures and could easily go through a full day of shooting on a single charge. The only times we were able to drain the battery significantly was with both Wi-Fi and GPS enabled, alongside extended use of live view. If these habits are closely mirror your own, you'll want to look into a spare battery and/or the optional BG-E13 battery grip which can double your battery capacity.