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JPEG Tone Curves / dynamic range

Our Dynamic Range measurement system involves shooting a calibrated Stouffer Step Wedge (13 stops total range) which is backlit using a daylight balanced lamp (98 CRI). A single shot of this produces a gray scale wedge from the camera's clipped white point down to black (example below). Each step of the scale is equivalent to 1/3 EV (a third of a stop), we select one step as 'middle gray' (defined as 50% luminance) and measure outwards to define the dynamic range. Hence there are 'two sides' to our results, the amount of shadow range (below middle gray) and the amount of highlight range (above middle gray).

To most people highlight range is the first thing they think about when talking about dynamic range, that is the amount of highlight detail above middle gray the camera can capture before it clips to white. Shadow range is more complicated; in our test the line on the graph stops as soon as the luminance value drops below our defined 'black point' (about 2% luminance) or the signal-to-noise ratio drops below a predefined value (where shadow detail would be swamped by noise), whichever comes first.

Note: this page features our new interactive dynamic range comparison widget. The wedges below the graph are created by our measurement system from the values read from the step wedge, the red lines indicate approximate shadow and highlight range (the dotted line indicating middle gray).

Cameras Compared

The EOS 5D Mark III exhibits a tone curve that is virtually identical to its predecessor, the 5D Mark II. By default the Highlight Tone priority feature is switched off but the highlight roll-off is smooth, with almost 4 EV of highlight range. Turning HTP on gets you an additional stop and even flatter tone curve in the highlights. This makes for a very gentle transition from highlight detail to clipped white. Unfortunately the camera's Auto Lighting Optimizer (ALO) feature is not triggered by our dynamic range test scene but you can see its impact in a real-life sample on the features page of this review.

Color Modes

The EOS 5D Mark III offers seven different 'Picture Styles', which are essentially color response presets applied to in-camera JPEGs. As we have seen in previous generation EOS cameras, the various Picture Styles use either one of two tone curves, the first more contrasty curve for the Standard, Portrait, Landscape and Monochrome Picture Styles, and a slightly flatter curve for the Neutral and Faithful Picture Styles. Neither curve delivers more dynamic range and they both clip highlights at the same point.

ISO 50

The Canon EOS Mark III's base ISO setting is 100. However, the camera also offers an extended 'L' setting which is equivalent to ISO 50. This lower sensitivity setting is essentially ISO 100 with 1 EV additional exposure and a tone curve adjustment to arrive at a final exposure with the correct brightness. As you can see in the graph above the penalty is a significant decrease in available highlight range. Given this difference, we would advise shooting at or above ISO 100 to maintain maximum dynamic range, using ND filters instead for situations that require a longer exposure.
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Total comments: 6
By Rob728 (2 days ago)

I have just bought a 5d mkii, and when doing a comparison test (nothing scientific) against my 50d I find that the 5d3 seems to under expose by upto 1stop, is this normal?

By schutzaphoto (1 month ago)

I work in Nyc as a fashion photographer and I have to say the the 5d series are the most used cameras out side of medium format cameras .Ive been shooting with the mark 3 for over a year after shooting with the mark 2 for 2 years great both great cameras. You can see the shots I've taken with it on my website hope it helps!!

Comment edited 3 minutes after posting
1 upvote
Cyrus the Great
By Cyrus the Great (2 months ago)

Nikon D800 is clear winer over 5D iii in every things. Nikon has much sharper lens.
don't know why some people buy Canon???!!!!!

1 upvote
R D Carver
By R D Carver (2 months ago)

'Some people' buy Canon because they earn their living using a camera. Oh man, you should see those forests of white and red-ringed lenses in the pro pit at every major sporting, media and news event! 'Some people' are winning the major competitions, filling the fashion and nature magazines and filming box office busting movies with Canon. "Nikon has much sharper lens" Which lens exactly? Give a photographer a Canon 5D MKIII and an EF 70-200mm F/2.8 L IS II USM Lens and he can take on the world. Nikon is good, Canon is good why get tribal? it is so petty and amateur. At work I can pick up a Nikon/Sony D800 body or a Cannon 5D MKIII. I prefer the Cannon because I don't like the white balance on the Nikon. Others are happy to use the Nikon, but the die hard Nikon enthusiasts are disappointed that Sony make the sensors for Nikon. In comes Sony in comes the green tinged white balance.

By WillieG (1 month ago)

No cameras white balance is perfectly neutral. That's why we have the ability to manually change it on the camera and even fine tune on some of the higher end models. Nikon cameras do run slightly toward the cool side, but they can always be fine-tuned to be neutral in-camera. Canon cameras have always leaned towards the orange color tint. Luckily for Canon the end result is a slightly warmer image that many photographers like the looks of. Few pros would buy a camera that couldn't be made to produce true colors. And that forest of white lenses has been thinning out quite a bit since the advent of the Nikon D3. I'm one die-hard Nikon enthusiast who's ecstatic with Sony sensors. No other brand can even match their dynamic range.

Comment edited 6 minutes after posting
By mufflon (3 months ago)

thx for putting the Shadow noise test in your review. it was time to show that quite big difference.

Total comments: 6