A 24.1-million-pixel, APS-C sensor with no anti-aliasing filter should ensure large and sharp images from Nikon's new enthusiast-level DSLR, but there's a lot more to the D7100 than that. Read the Nikon D7100 review...
Nikon D7100 review – Noise, resolution and sensitivity
These images show 72ppi (100% on a computer screen) sections of images of a resolution chart, captured using the Sigma 105mm, f/2.8 macro set at f/5.6 . We show the section of the resolution chart where the camera starts to fail to reproduce the lines separately. The higher the number visible in these images, the better the camera’s detail resolution is at the specified sensitivity setting.
I was particularly keen to see how well the D7100 performs with our resolution charts. The raw images have been converted to TIFF files in Nikon’s View NX2 software, and then further processed in Adobe Camera Raw. At ISO 100 and 200, the camera is able to resolve all the way to the end of our resolution charts, which is a staggering performance and a first for an APS-C-format camera.
A little moiré patterning can be seen further down the charts, but all the lines are distinguishable right up until the end. There is a sharp tail-off at ISO 400, down to the 30 marker, which is more in line with what we would expect of a camera at this level.
There are still signs of detail further up the charts at this setting, but it is at the 30 marker that moiré patterning in particular disrupts the clear distinction between the lines.
Detail in JPEG files from the D7100 can only match the raw files up to the 30 marker at ISO 100. It is clear that for the crispest possible detail, shooting in raw format at ISO 100 or 200 is essential.
With 24.1 million pixels, the D7100’s sensor is more crowded than the 16-million-pixel units in the D7000, Pentax K-5 IIs or Fujifilm X-Pro1. It therefore comes as little surprise that the D7100 suffers more from noise – luminance noise is present in all sensitivities and can be seen when viewing an image at 100%.
There is a notable increase in luminance noise at ISO 800 in dull conditions, but its appearance is uniform so images are still relatively clean. At the extended ISO 12,800 and 25,600 settings, luminance noise is prominent, as are chroma noise and banding. As such, I would recommend sticking to the native ISO range.
At the enthusiast DSLR level, the camera is unparalleled for work in good light, but there are other, lower-resolution cameras available, such as the Nikon D5200 and Sony Alpha 77, that offer better control of noise for low-light work.
As always, it should be remembered that higher-resolution cameras give greater scope for scaling an image down to create what appears to be crisper images.
Image: At ISO 3200, detail in the D7100 is rather mushy because luminance noise is prominent and non-uniform. There are other cameras, such as the Fujifilm X-Pro1, that provide crisper detail