Canon 6D - £1,459 / US$1,900 / AU$2,300
Canon 5D Mark III - £2,122 / US$3,150 / AU$3,600
Nikon D600 - £1,189 / US$2,000 / AU$2,120
Nikon D800 - £1,951 / US$2,800 / AU$3,200
All of the cameras in this category are full-frame DSLRs, since pricing has dropped significantly over the past couple of years.
Both Nikon and Canon has an 'entry-level' full-frame camera, designed to appeal to advanced enthusiasts, or perhaps pros looking for a second body. They offer many of the same specifications of the more advanced cameras, but in smaller and more affordable bodies.
The Canon 6D features a 20.2 million-pixel full-frame sensor, while the Nikon D600 sports a 24.3 million-pixel device. The Nikon also pips the Canon in terms of autofocusing, with its 39 point AF module, compared with just 11 from the 6D.
However it's the 6D that has the edge in terms of low light shooting, offering a native sensitivity run of ISO 100 – 25600, which can be expanded down to ISO 50 and up to ISO 102400. Meanwhile, the D600 offers 100 – 6400 natively, expandable to 50 – 25600. Our labs tests also show that the Canon beats the Nikon for signal-to-noise ratio performance throughout the sensitivity run, for both JPEG and raw format files.
If you're not often shooting in very low light though, it will likely be other factors that grab your attention. One small, but appealing, feature of the D600 is its 100% field of view optical viewfinder. The 6D offers a 97% field of view, so there's a chance that something may end up in the final photo that you didn't notice in composition.
In terms of other aspects of image quality, colours from the Canon tend to be a little warmer, and therefore may be more pleasing to the eye. By comparison, the D600's images are a bit more true-to-life.
The 6D features built-in Wi-Fi, the only full-frame DSLR currently on the market to do so (the Sony Alpha 7 and 7R also have WI-FI connectivity, but they're compact system cameras). This is a particularly useful function for quickly sending across shots to a smartphone or tablet for sharing online, and even more so for remote-controlling the camera. This may be appealing to nature photographers, for instance.
The D800's 36.3 million pixel sensor – still offering the highest resolution on the market – caused quite the stir at the time of launch. A variant of the D800 (the D800E) is also available without the anti-aliasing filter, which may appeal to landscape photographers since the detail resolution is greater.
Meanwhile, the 5D Mark III features a still-respectable 22.3 million-pixel sensor. Generally it's Nikon cameras that feature a more populated AF module, but it's the Canon here that pips the Nikon. The 5D Mark III features 61 AF points, 41 of which are cross-type and sensitive down to f/4, and five that are sensitive down to f/2.8. By contrast, the D800 features 51 AF points, 15 of which are cross-type.
As we would expect at this price point, both the cameras offer a 100% field of view viewfinder, while both also offer a 3.2-inch LCD screen – the Canon's just slightly beats the Nikon with 1040k dots, compared to 921k dots.
Once again, it is the Canon that offers the most for low-light shooting, offering ISO 100 – 12800 in the native range, which can be expanded to 50 – 102400. The D800/E offers 100 – 6400, which is expandable to 100 – 25600. Our labs tests show that the two cameras are actually pretty closely matched in terms of signal to noise ratio performance, but it's the Canon that has the edge.
In terms of colour reproduction, the D800 has been known to have the occasional problem with producing slightly cold images. Meanwhile, the 5D Mark III is capable of producing beautifully saturated images straight from the camera.
Read our full Canon EOS 6D Review
Read our full Canon EOS 5D Mark III Review
Read our full Nikon D600 Review
Read our full Nikon D800 Review