The cameras we'll be looking at are:
This selection includes some of the most popular full frame DSLRs available. However, you might notice it omits the Nikon D4S and Canon 1D X – that's because potential buyers of those pro-focused cameras are unlikely to also be considering other models.
Also, while the included Sony A99 isn't technically a DSLR (because it uses SLT technology) we've still included it here as it's still considerably more DSLR-like than the mirrorless Sony A7 cameras. Those impressive full frame devices will be included in our upcoming high-end mirrorless comparison.
These are not small cameras. Even smaller models like the Canon 6D and Nikon D750 are big compared to crop sensor DSLRs and mirrorless cameras. This is because they have to house both a large full frame sensor and a mirror. That said, some professional and enthusiast photographers argue full frame DSLR cameras offer good ergonomics as a result.
Weighing in at 755 g to 980 g before you've added a lens (but with a battery and memory card) you are not going to want to carry any of these cameras around unless you are going to be doing some serious shooting, especially if you are also carrying a selection of lenses.
Full frame (36 x 24 mm) CMOS sensors are a given for cameras in this category, with the major specification difference being megapixel count. Most of the cameras come in between 20 and 25 megapixels, which will offer more than enough detail for most users. However, the Nikon D810 with it's monster 36.3 megapixel count and the newer Canon 5Ds with its wonderfully ridiculous 50.6-megapixels (which blew us away when we reviewed the camera) offer a whole other level of resolution.
It's also worth noting here that the Canon 5Ds is also available (for US$200 more) as the 5Ds R, which uses a low-pass cancellation filter to offer increased sharpness, though also increases the possibility of suffering moire.
With manufacturers each using their own image processor, it can be difficult to compare exactly what this means when comparing brands. The more useful insight comes from looking at the differences between the same brand of camera, such as the Canon 5Ds using newer dual DIGIC 6 processors compared to the DIGIC 5+ in the 6D and 5D M3.
The big full frame sensors in these cameras allow them to gather more light than their smaller sensored counterparts and, as such, they enjoy wide ISO ranges and are able to deliver the goods in a variety of lighting conditions.
The figures given here are native or recommended ISO ranges, where the camera should deliver better results, though to get the best color and lack of noise you'll still not want to reach the higher ends of those ranges. That said, for times when you really need a high ISO most of these cameras have expanded ISO options. In the case of the Canon 6D and 5D III this allows settings up to ISO 102,400.
Luckily, things get a lot better when it comes to Full HD and HD recording, with all of these shooters capable of recording 1080p footage. While the other cameras can record this at a smooth 60 fps, the Canons are limited to 30 fps. Dropping the resolution to HD 720p and the cameras which couldn't do 60p/50 fps at 1080p can shoot at the increased frame-rates.
Most of these cameras offer optical viewfinders with a standard of 100 percent full frame coverage, however the Canon 6D only has 97 percent frame coverage, which means users will see a slightly cropped version of what they are shooting. Notably the Sony A99 uses an electronic viewfinder, and while this OLED viewfinder was very impressive when the A99 was initially released, the electronic viewfinders we've seen in more recent cameras are much improved.
While all of these shooters have a hot-shoe for attaching an external flash, only the Nikons also a feature a pop-up flash.
DSLRs are well known for their impressive battery life, and most of these cameras live up to that reputation. Only the Sony A99 lacks in the battery-life department (probably because it uses an electronic viewfinder / monitor) by being able to deliver 500 shots on a single charge. With a battery life of up to 1,400 shots, the likes of the Canon 5Ds can keep shooting much longer than most other cameras.
All of these cameras use the type of mount you would expect for their manufacturer. One thing that is worth considering is that there has been very little news on the Sony A mount, with new all recent flagship cameras using the Sony E-mount.
Cameras with full frame sensors don't come cheap and the starting price here is US$1,400 for the Canon 6D without a lens. The Canon 5Ds is the most expensive of our line-up at $3,400, and its "R" sibling comes in at $200 more.
While they are facing undoubted and mounting competition from mirrorless counterparts, full frame DSLRs still have a lot to offer photographers. They can offer a good balance of image quality and performance, along with the ability to use established lens systems which most users who are considering buying a full frame DSLR will probably already be invested in.
The more affordable cameras in our comparison like the Canon 6D and Nikon D750 can deliver great quality images. However, the solid build and performance boost of the Canon 5D III will, for many working pros who don't always need the machine gun fire of the Canon 1D X or Nikon D4S, be money well spent. Equally for those who need extra resolution, the Nikon D810 or Canon 5Ds will be the way to go.
Of the line-up, the Sony A99 is arguably the harder sell. That's because things appear to be slowing down with the A-mount, and compared to the tech in newer Sony cameras like the A7R II, this DSLR is looking rather dated.
However, whichever of these full frame DSLRs you end up opting for, it will be able to turn out great quality images, but remember to budget for any lenses you will also need to take the images you want.