Inside the EOS 5D Mark III

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Thanks for reading! Andrew.


Canon announced the new EOS 5D Mark III at the beginning of March. There’s been a lot of interest about this camera as speculation has built regarding the replacement to the EOS 5D Mark II (released in September 2008). Three and a half years is a long time in terms of digital camera development, and as I own a 5D Mark II, I thought it would be interesting to look at some of the features of the 5D Mark III to see where the improvements are that would encourage me (or other photographers) to upgrade to the new model.

One of the interesting things about digital cameras is the rapid rate at which the technology has matured. Anyone who has used one of the older digital Canons, such as an EOS 300D or 10D, will appreciate how much better newer models are. The autofocus is faster and more accurate, the LCD screens on the back of the camera are much bigger, and – most importantly of all – image quality has greatly improved. If you own any of the lastest EOS cameras it’s difficult to see how the image quality can be bettered. And even if it can, does the the increase in image quality matter? At what point is the quality good enough for most people? And once that point is reached, what does Canon (and the other camera manufacturers) do to entice consumers and professionals alike to buy their latest models?

As I see it digital camera development is at the point where if you bought any EOS camera released in the last two or three years the image quality of your camera is all you need for most purposes. The extra quality gained by upgrading to the very latest models isn’t going to make you a better photographer – and most photographers I’m sure are aware of that. Which leaves Canon with a problem – how can they encourage photographers to buy their latest cameras when the cameras most of them already own are good enough? The EOS 5D Mark III has some of the answers.

Similarities with the EOS 5D Mark II

First, let’s look at the areas where the 5D Mark III is similar to the 5D Mark II:

Megapixels – the 5D Mark III has a 22.3 megapixel full frame sensor compared with the 21.1 full frame sensor of the 5D Mark II. There’s a bit of extra resolution, but not much. If you want to make extra large prints then you may want more megapixels, but I’m sure most people will be happy with 21 or 22.

Image quality at low ISOs – I’ve read nothing to suggest that the image quality from the EOS 5D Mark III is better at low ISOs. That will become clearer as more people test the camera and give their verdict.

Differences from the EOS 5D Mark II

These aren’t all the differences, this is just an overview. These are the things that I wish my EOS 5D Mark II had – plus a few that may interest others but aren’t important to me.

EOS 5D Mark III AF sensor

61 point autofocus

This is the major difference between the two cameras. Until the 5D Mark III the best autofocus systems were found on the EOS 7D and the 1D series cameras. Realistically, One series cameras are beyond the budget of most enthusiasts, so that leaves the EOS 7D as the natural camera of choice for anyone who shoots a lot of wildlife or sport.

I shoot primarily static subjects, yet there are still times when I shoot something that moves and would appreciate a better autofocus system than the one on my EOS 5D Mark II. And I’m sure there are plenty of photographers that feel the same way. They don’t need the latest and best autofocus system all the time, but it would be nice to have it to hand when they did.

Owners of the EOS 5D Mark III get a new 61 point autofocus system that is shared with the EOS 1Dx. It’s better than the EOS 7D or even the 1D Mark IV. The only downside is that the AF controls are more complicated and it will take a while to learn how to get the best out of the camera if this level of AF sophistication is new to you – there’s more information on the Canon USA site here, here, here, here and here.

Two stop noise reduction

The new Digic 5+ processor in the 5D Mark II (17 times faster than the 5D Mark II’s Digic 4 processor) enables a couple of significant improvements in image quality. One of them is a two stop performance in noise reduction compared to the 5D Mark II. This means that a photo taken at ISO 6400 on the 5D Mark III should have the same amount of noise as a photo taken at ISO 1600 on a 5D Mark II. Impressive – and useful for anyone who uses the high ISO settings on their camera. It should be noted though that the two stop improvement only applies to JPEG files and not Raw. This is understandable – noise levels in Raw files are much harder to quantify because you can reduce noise by ‘exposing to the right’ and also the noise reduction in the latest versions of Raw processors like DPP and Lightroom produce excellent results. But Raw users should still see a visible improvement.

The top standard ISO speed on the 5D Mark III is 25600, which means this camera can virtually see in the dark. I’ve shot in dark conditions with my 5D Mark II and it picks up more than my eye can see.

Chromatic aberration correction

Chromatic aberration correction is another useful feature. When this function is enabled the camera will automatically correct chromatic aberrations caused by the lens. This works for Canon lenses only (not third-party lenses). The camera has information stored for about 25 lenses and you can add more using the EOS utility software that comes with the camera, choosing from 80+ Canon lenses. Before this feature the easiest way to correct chromatic aberrations was to shoot in Raw and use DPP (or another Raw processor – Lightroom also contains correction data for many Canon lenses).The 1Dx also has chromatic aberration correction but isn’t available in the stores yet.

Now this is of limited interest to me because I shoot Raw –  but if I had a 5D Mark III it may tempt me into using JPEG more because it takes away one of the advantages of Raw. An interesting thought. I know that many wedding photographers use JPEG (to save processing time) and I’m sure that they would welcome the chromatic aberration correction feature.

In-camera HDR

Another feature apparently enabled by the Digic 5+ processor. It’s not one that interests me – I think HDR (High Dynamic Range) photography is a gimmick used by photographers to compensate for lack of creative vision. But if you want it, the 5D Mark III has it.

Multiple exposures

This is a potentially useful feature. I’ve seen people use multiple exposure on other cameras to reduce noise. Taking several images and merging them together reduces noise which occurs at random points within the frame. As long as the camera is on a tripod and the frames align precisely it seems like a good way of reducing random noise produced by high ISOs (not long exposure noise, which occurs in a fixed pattern). Interesting? We’ll see what people do with it – it really does seem to have a lot of creative potential (more on that here).


The 5D Mark III has a new viewfinder with 100% coverage and the translucent liquid crystal display the EOS 7D uses to display all those lovely AF points in various configurations. I’m drooling just thinking about it.

Mode dial lock

Useful (although you can have it fitted retrospectively to the 5D Mark II), I’m always knocking the mode dial. I like that the On switch has been separated from the Quick control dial lock as well.

Bigger LCD screen

The LCD screen on the back of the 5D Mark III is bigger. It has the same 3:2 aspect ratio as the camera’s sensor, which means it plays back images without cropping them, so they are displayed at a larger size than on the 5D Mark II’s screen.

This is great for Live View, especially if you use it for fine focusing with close-up, macro or landscape work. It’s also useful for exploring other aspect ratios. If you want to explore the square, panoramic or 4:3 formats just activate Live View, set the required aspect ratio, and it will be displayed on the LCD screen with the unused parts of the frame blacked out, perfect for framing.

If you use the JPEG format the JPEG file will be cropped to the selected aspect ratio, if you use Raw the file contains the entire frame as recorded by the sensor, but with the aspect ratio information appended. If you open it in DPP it will recognise the aspect ratio and crop accordingly – if you open it in another program you’ll have to crop it yourself.

EOS 5D Mark III dual card slots

Dual card slots

Very, very useful, and about time. I like to go away on trips without taking a computer with me. I have a portable hard drive with memory card slots I can back my memory cards up to but I’d prefer dual card slots. It’s much easier and means that there’s one less device to carry.

Having said that, at the risk of tempting fate, I’ve never had a problem with a memory card. In fact, at EOS magazine I tried to destroy an old memory card once and couldn’t. I ran it through the washing machine, froze it in ice, threw it against the wall, stamped on it as hard as I could and ran it over with a car – it still worked and all the images were intact. So it’s pretty hard to damage them, although memory card corruption is always a potential problem. But nevertheless, dual memory card slots are great for peace of mind, especially on important shoots.

EOS 5D Mark III iFCL exposure sensor

iFCL Evaluative metering

Canon’s intelligent, focus, colour and luminance evaluative metering system has appeared on every new camera (except the 1D Mark IV and 1Dx) since the EOS 7D. The previous exposure sensor, which was only sensitive to brightness, not colour, has been replaced by a new two layer colour sensitive exposure sensor (pictured above) that is supposed to give more accurate results.

The main benefit of the new system is that it has 63 zones (compared to the 35 zones of the 5D Mark II) which should help the camera make more accurate exposure calculations. In my experience the new sensor is no more accurate than the previous one. The fundamentals of exposure haven’t changed. If you take a photo of a light subject (such as a white flower) the camera will underexpose, and if you take a photo of a dark subject it will overexpose. It doesn’t matter which exposure sensor your camera has or what exposure mode you use – it requires intervention from the photographer to get the right exposure.

Movie mode

Yawn…that’s my usual response to talk about movie mode. It’s interesting, and the movies made with these cameras are amazing, but I’m a photographer, not a videographer, and the steep learning curve involved with learning to use digital SLRs to make movies doesn’t interest me. I’d rather spend the time learning more about photography. However, if you’re into making movies you’re probably very excited by the 5D Mark III. There’s a run-down of the new movie mode features here.


It’s clear that Canon have put a lot of though into the EOS 5D Mark III and they’ve come up with a camera that’s a significant improvement from the 5D Mark II. Image quality alone isn’t a good enough reason to upgrade, and the 5D Mark III has plenty of other features, not least the 61 point AF system and 100% viewfinder, which will encourage photographers to buy the camera.

Who will buy this camera? I’m sure that many professionals are excited by it, but what about enthusiasts? For all the benefits, I’m not going to upgrade from the 5D Mark II. I’m quite happy with the image quality I get from it and the 5D Mark III, let’s face it, isn’t cheap.

I suspect that the 5D Mark III will appeal to enthusiasts who have outgrown their crop-sensor cameras or want to replace an older model and would like to move up to a full-frame camera. At the moment, they have the choice between the 5D Mark III, and the 5D Mark II which will remain on the market at a lower price point, as well as the top-of-the-range EOS 1Dx.

I’ve written this article without the benefit of using an EOS 5D Mark III, so here are some reviews from photographers who have used the new camera:

Jeff Ascough

Niel van Niekerk

Ryan Brenizer

Martin Bailey

Martin’s review is the most detailed, and there’s a podcast to go with it. The download and subscription details are at the bottom of his post.

Inside EOS

This is the first in a new series of articles written for Canon EOS users. They’ll be filed under the Inside EOS category. My next article will be a guide to upgrading your camera (update: you can read it here). It will follow on from some of the ideas discussed here – when do you know if it’s time to upgrade your EOS camera and which model should you choose?


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2 Responses to “Inside the EOS 5D Mark III”

  1. Nick P says:

    Nice review – although I’d be interested to see if you change your mind on anythng after actually using the Mk III.

    I’ve also go a Mk II and have made the decision to upgrde later this year (need to gather some funds!!). The main reasons are the increase AF points and higher/improved ISO.

    I shoot a lot of travel stuff and often dont’ have the time or inclination to set up lighting (prefer natural light). However when you’re shooting in temples for example the low light can make it difficult (if you don’t have a tripod) to keep the image sharp and even then it can come out a little noisy.

    Also the HDR option is interesting. I aprpecaite what you say and agree that 99% of the time HDR is used as a creative response and more often than not is over-blown. However there are many good uses of HDR where you wouldn’t necessarily even notice it. When you’ve got an image with a huge dynamic range – perhaps shooting in a room with bright windows and dark shadowy corners. The only options here are to either take multiple different exposures and blend together manually or use HDR (subtly – I’m not talking halos here!).

    Finally, like you, when I’m travelling I don’t tend to take a computer with me. I used to have a Jobo GigaOne to back up my cards but it needs replacing. You mention you use a a similar device. Any recommendations on good in-the-field backup devices?

  2. Andrew says:

    Nick – I use a Digital Foci Photo Safe. The Mark II version is available from the link below. There’s no UK distributor that I know of.

    I think the multiple exposure function on the EOS 5D Mark III will be handy for shooting interiors. Good point about the better high ISO performance being useful for shooting in temples etc too.

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