Nikon D3100 High ISO NR

Nikon D3100 High ISO Noise Reduction

The Nikon D3100 offers just two noise reduction settings: On and Off, with On being the default. (Note that the D3000's noise reduction setting defaulted to Off.) The setting combines perceptual noise reduction as well as dark frame noise reduction, the later only being applied to exposures longer than 8 seconds. It looks as though noise reduction is applied at all ISOs when On, as low ISO images have slightly less noise when it's On vs Off. Nikon says noise reduction is only performed at "high ISO sensitivities" when set to Off (they don't say at what ISOs), and that the amount of noise reduction is reduced compared to the On setting.

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. We've only taken crops at ISO 800 and above, since the effect of NR at lower ISOs is very subtle.

The above crops show the effects of the two available levels of noise reduction, under our studio HMI lighting we use to simulate daylight. Click on the crops to load full resolution images.

As you can see, the "On" setting starts to affect detail in the red fabric noticeably at ISO 1,600 and above. The D3100's noise reduction works quite well, but you should be able to do bit better by shooting with NR turned "Off" and using a good noise-filtering program after the fact. (Even better, shoot RAW and apply your own noise filtering.)

How does the Nikon D3100 compare with competing cameras? See the crops in the following table.

As you can see, the Nikon D3100 appears to have the best noise versus detail handling of the group. Using defaults would have put the Nikon D3000 at a bit of a disadvantage in the above table, since it defaults NR to "Off" while others default to enabled, so we've used the non-default "On" setting for it. The Canon T1i comes in a very close second, but struggles with low contrast reds even at ISO 800. The Sony A390 (which uses the same sensor and processor as the Sony A290) leaves quite a bit of blotchy chroma noise, coming in third. The Nikon D3000 places last, with quite a dramatic difference between it and its successor.