Nikon Coolpix A review – Noise, resolution and sensitivity
These images show 72ppi (100% on a computer screen) sections of images of a resolution chart, captured using the 18.5mm lens set to 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.
At ISO 100, the Coolpix A resolves up to almost 32 on our test chart, which is a very impressive number for a camera that has a resolution of 16.2 million pixels. In fact, it is about what we would expect from a camera with more than 20 million pixels. The detail resolution gradually declines as the sensitivity increases, but even at ISO 1600 the camera and lens can still resolve to around 28 on our chart.
In JPEG images noise is very well controlled, and it isn’t until around ISO 6400 that colour noise seems to creep in a little, with a hint of luminance noise softening detail slightly and reducing the resolution to around 26.
The Hi1 and Hi2 sensitivities suffer from colour and luminance noise to the detriment of image quality. Hi2 (ISO 25,600 equivalent) should be avoided, as it appears to push the sensor a little too far. Magenta noise is apparent and there is some linear pattern noise in dark areas.
In reasonable light I would be happy to shoot JPEGs with the ISO set to 100-3200 with little concern for noise. Raw images allow slightly more detail to be prised from the image, although it doesn’t really increase our test chart result, merely making images look sharper. Of course, it is far easier to reduce colour noise, and at higher sensitivities colour noise shouldn’t be an issue at all for raw shooters. Luminance noise is unavoidable as the ISO setting is increased, but the Coolpix A sensor does a good job of keeping this to a minimum. With careful exposure and editing, images look excellent even at higher sensitivities. As most users will take their images at between ISO 100 and 1600, I wouldn’t be too concerned about noise when using the Coolpix A, unless images are heavily edited for brightness.
