Facebook Pixel Review: Comparison Canon 5D MarkIII vs the Canon 6D

Review: Comparison Canon 5D MarkIII vs the Canon 6D

EOS 5D Mark III and EOS 6D

Now that Canon has two semi-professional full-frame cameras, the EOS 5D Mark III and EOS 6D, naturally photographers wonder which is the best model for them. As a former Technical Editor of EOS Magazine (the best magazine Canon owners could possible buy) I would like to share my insights.

But first, if you’re in the market for a full-frame EOS camera, let’s not forget the top of the range EOS 1D-X. This is a high-end, professional camera with a price tag to match. It’s big and heavy and built for the demands of a professional photographer’s life. Most photographers don’t need this much camera, but it’s interesting to look at because its size and price put Canon’s other full-frame cameras into perspective. Here’s a photo:



Big, right? The body alone weighs 1340 grams (nearly three pounds) and will set you back nearly $6800 USD+tax if you buy it from B&H Photo Video. The weight and price alone mean this camera isn’t suitable for most non-professional photographers, leaving Canon’s other full-frame models, the EOS 5D Mark III and EOS 6D, as the available choices.

Let’s compare – Canon 5D MarkIII vs the Canon 6D

Key differences

Let’s start by looking at what could be the deciding factor for some people – price. The EOS 5D Mark III costs around $3299. The EOS 6D is $1500 less expensive at $1799 (body only prices). That’s a huge difference, so why would anyone choose the 5D Mark III over the 6D? Let’s take a look.

Size and weight

  • The 5D Mark III weighs around 950g/2.1 lb.
  • The EOS 6D is Canon’s smallest and lightest full-frame digital SLR. It weighs 755g/1.6lb (body only, but including memory card and battery). It is also slightly smaller.

I own an EOS 5D Mark II and I can tell you that it gets heavy when I carry it around all day. If you’re planning to carry a camera on a strap over your shoulder for hours at a time, then it makes sense to buy the lighter model, and use light lenses (such as the EF 50mm f1.4 lens in the photo below).


EOS 6D with EF 50mm f1.4 lens

On the other hand, if you are a landscape photographer, keep the camera mainly in the studio, or just take it with you on location and use it for a couple of hours then pack it away again, the weight probably makes no difference.

Bottom line: If size and weight are critical, then go for the EOS 6D. But not before considering autofocus performance!


Autofocus performance is the major difference between the two cameras. It is a big factor if you are into photographing sports, action, portraits or any moving subject.

  • The EOS 5D Mark III has a 61 point AF array with up to 41 cross-type AF sensors (depending on the maximum aperture of the lens mounted on the camera). Along with the EOS 1D-X, it has Canon’s most advanced autofocus system.
  • The EOS 6D has an eleven point autofocus (AF) array with one cross-type AF sensor in the centre.

Cross-type AF points are more sensitive, and therefore focus more accurately, than other AF sensors. This is especially important if you work at wide apertures (i.e. between f1.0 and f2.8) as depth-of-field is so narrow at these settings.

As an example, let’s look at how it works with portrait photography. Imagine that you’re taking a portrait of someone with an 85mm lens set to f1.8. Accurate focus is critical as depth-of-field is very narrow at this setting – you may have less than an inch of sharpness to play with. The normal way to focus in this situation is to use the AF point closest to the model’s eye. The photo below shows how this works by overlaying a diagram of the EOS 6D’s AF array over a portrait. The single cross-type AF point in the centre is shown in green, and the AF point the photographer would have to use is in red:

EOS 6D autofocus array

You can see the problem right away. As the only cross-type AF point is in the centre, you can’t use it to focus unless the model’s eye is also in the centre of the frame. You have to use one of the less sensitive, and therefore less accurate, AF points at the edge of the array.

With the EOS 5D Mark III the story changes. With up 41 cross-type AF points available (shown in red), it is far more likely you will find one to cover the model’s eye. The end result is that you will get more in-focus photos.

EOS 5D Mark III autofocus array

You can learn more about the autofocus of the EOS 5D Mark III in my article Understanding EOS Autofocus: The EOS 5D Mark III and EOS 1D-X

Bottom line: If autofocus performance is critical, then (budget allowing) go for the EOS 5D Mark III.

Wi-fi and GPS

This is another major difference between the two cameras. However this time, and somewhat counter-intuitively, it is the EOS 6D that has the features and the 5D Mark III that does not.

  • The EOS 6D’s built-in GPS lets you geotag your photos with the camera’s location as you take them. You can then use that to see where they were taken on a map, help organize or search your images in Lightroom, or as extra information if you sell your photos to a stock library. If you want to do the same with an EOS 5D Mark III, you have to buy a GPS unit separately.
  • The EOS 6D’s built-in wireless lets you upload your photos via a local wi-fi connection to a computer as you take them (useful in a studio or even on location if you have a laptop with you), upload photos to Facebook, or remotely control your camera using a Smartphone app. Again, you have to buy a separate wireless unit, which comes built-in to a portrait grip, to do the same with an EOS 5D Mark III.

Bottom line: If you need GPS or Wi-fi, then buying the EOS 6D will save you a lot of money.


EOS 5D Mark III with EF 24-70mm f4 lens

Dual card slots

  • The EOS 6D has a single card slot for an SD type memory card (it also accepts SDHC and SDXC cards)
  • The EOS 5D Mark III has two card slots. One takes CF cards, and the other SD (plus SDHC/SDXC cards)

One benefit of dual card slots is speed. CF cards are faster, which helps give higher burst speeds and assists with recording movies.

Another is security. You can set the EOS 5D Mark III to save photos to both the CF card and SD card slots at the same time, giving you a back-up in case one fails. Bear in mind it will slow the camera down as it takes longer to write a file to two cards, but it may give you peace of mind on important shoots. I imagine wedding photographers will greatly appreciate this feature.

Having said that, if you look after your memory cards, and buy a reputable brand, they are highly unlikely to fail. Most memory card failures are the result of corruption caused by user error, such as removing a card from a reader while the computer is writing to it.

Bottom line: If dual card slots matter to you, then you need the EOS 5D Mark III.

EOS 5D Mark III dual card slots

The dual card slots of the EOS 5D Mark III.

Minor differences

There are lots of minor differences between the two cameras, so I’ve provided some links to in-depth reviews so that you can get more information before making a purchasing decision. You’ll also see some photos taken with both models. In the meantime, if you own or have used either of these cameras, why not tell us what you think in the comments. Why did you choose one or the other, and do you think you made the best choice?

EOS 5D Mark III reviews

EOS 6D reviews

Understanding EOS

Understanding EOS ebook cover

My ebook Understanding EOS is written for photographers who want to learn to get the best from their EOS cameras. Click the link to learn more.

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Andrew S. Gibson
Andrew S. Gibson

is a writer, photographer, traveler and workshop leader. He’s an experienced teacher who enjoys helping people learn about photography and Lightroom. Join his free Introducing Lightroom course or download his free Composition PhotoTips Cards!

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