Dynamic range expansion

Like previous Canon DSLRs the Canon EOS 5D Mark III comes with the dynamic range enhancement modes Highlight Tone Priority (HTP) and ALO (Auto Lighting Optimizer). The former improves a scene's highlight detail, while the latter increases shadow detail in high-contrast scenes. The High Dynamic Range (HDR) mode is a new feature on the 5D Mark III and increases a scene's dynamic range by combining several exposures into one.

Auto Lighting Optimizer

The 5D Mark III comes with the same Auto Lighting Optimizer feature that has been included in a few generations of Canon DSLRs now. The function lifts shadow detail in high-contrast scenes but in less contrasty conditions, the feature is not doing anything worth commenting on. Here is an example of a high dynamic range situation, and the effect of having ALO off and switched on to its various settings. Looking at the detail of the boat's hull there is difference in the shadow area, but it is subtle, even at the 'Strong' setting.



ALO Standard

ALO Strong

Highlight Tone Priority

The EOS 5D Mark III features the same 'Highlight tone priority' option that's found all current generation EOS cameras. It is activated on the third page of the shooting menu, and improves a scene's highlight detail. In our studio tests, it adds an additional stop of dynamic range in the highlights. In the real world it produced a clear, if subtle improvement, allowing the user to retain some detail in highlight areas where they would otherwise have been lost. This can be seen in the texture of the white tarpaulin on the boat on the left.



Because of the way Highlight Tone Priority works, it limits the minimum available sensitivity setting to ISO 200; it's also unavailable with the extended (H) settings. One point worth noting is that the extra highlight range is retained in your Raw files too, making HTP a very useful option to give you a 'buffer' in contrasty conditions (we often leave it on by default).

HDR mode

The EOS 5D Mark III is the first Canon DSLR to offer a built-in HDR mode. When pressing the shutter button in this mode the camera takes three shots - one correctly exposed, one over- and one under-exposed. The three shots are then combined to an HDR image. Moving subjects in your scene will result in 'ghosting' effects and Canon recommends the use of a tripod or fast shutter speeds when shooting in HDR mode. That said, on the 5D Mark III the mode can auto-align images (which it can't on Canon' compact cameras), and unlike almost any other camera, it lets you save RAW files for later processing.

The 5D Mark III's HDR mode lets you fine-tune your HDR shooting experience through a range of parameters in the shooting menu.

The mode is accessed via the Shooting Effects button on the camera's left shoulder, and offers a range of parameters to play with. You can select the bracketing range (1 to 3EV or 'Auto'), the HDR effect (Natural, Art standard, Art vivid, Art bold or Art embossed) and you can specify if only the HDR image should be saved to the memory card, or all three captured shots plus the end result.

The effects on offer range from fairly natural to pretty surreal. Which ones you like most will depend on your personal preferences. While the effects differ quite substantially from each other the impact of the selected EV range is much more subtle. Below you can see an overview of all possible effects/EV range combinations.

Standard 1
Standard 2
Standard 3
Vivid 1
Vivid 2
Vivid 3
Natural 1
Natural 2
Natural 3
Bold 1
Bold 2
Bold 3
Embossed 1
Embossed 2
Embossed 3