Noise, Resolution and Sensitivity
Image: Shot at ISO 400 with a Nikkor 24-70mm f/2.8 lens, there is a lot of detail and no discernible image noise
For low-light situations, the D3S is one of the best DSLRs we have seen. The quantum efficiency of the sensor is very high for a full-frame model, meaning that it converts a large amount of the light photons it receives into electrical energy. This is what allows the D3S to use high equivalent ISO sensitivities with low levels of image noise.
The D4’s resolution is 4 million pixels higher than that of the D3S. Although this is a fairly conservative increase, it does mean the amount of noise can be well controlled, and at almost every sensitivity setting the two cameras seem to be on a par.
In-camera JPEGs taken on the D4 are relatively free of noise up to around ISO 1600. At this setting there is a hint of luminance noise in shadow areas, but nothing of concern. In fact, the usable sensitivity range is around ISO 100-6400. Images at ISO 6400 look like those taken at ISO 1600 settings of most DSLRs with APS-C-sized sensors.
Noise is visible at higher and extended sensitivities, although it is reasonably well controlled. Given the extremity of the settings, I would recommend shooting above ISO 128,000 only when absolutely necessary. However, what these settings do offer is the ability to take images handheld in extremely low light, just as with the D3S.
Even more detail can be recovered when editing raw files, where the amount of noise can be fine-tuned. That said, it doesn’t make the extended ISO settings much more usable, but custom sharpening and noise reduction do improve images taken at the ‘everyday’ ISO 100-6400 range.
In terms of image quality, the D4 doesn’t really do much better than the excellent D3S. Yes, it has a slightly higher resolution but there is little improvement in the amount of image noise.
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 lens. 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.
