Canon EOS 7D High ISO Noise Reduction
The Canon 7D offers four settings for noise reduction: Off, Low, Standard and Strong, and NR is applied at all ISOs. Its different noise-reduction settings also allow you quite a bit of flexibility in choosing how you want to make the trade-off between subject detail and noise levels. It's not clear that the "Off" setting truly eliminates the noise processing altogether, but it is true that it leaves a lot of fine/subtle subject detail there for you to work with. The combination of shooting with NR turned off and using a good noise-filtering program after the fact can produce very clean images with lots of fine detail in them.
See for yourself how the noise reduction works under both daylight and tungsten-balanced lighting. Click on any of the crops below to see the corresponding full-sized image. Since the Canon 7D applies noise reduction at all ISOs (despite its name), we've included crops at lower ISOs.
The above crops show the effects of the 4 levels of high ISO noise reduction, under our studio HMI lighting we use to simulate daylight. The Standard setting strikes a good balance between noise and detail, however subtle detail in the red cloth swatch already suffers quite a bit at ISO 1,600.
How does the Canon 7D compare with competing models? See the following table which compares at the default Noise Reduction setting.
As you can see from the above crops, the 7D performs well compared to other models, despite having the highest resolution and smallest pixel size. Much of the difference is just the default level of noise reduction selected by the manufacturer, with both Canons and the Nikon D300S applying the most NR by default, while the Pentax K7 applies the least. To see how the sensors actually compare in terms of high ISO noise, see our Canon E7D RAW comparison page.