With a full-frame 24.3-million-pixel sensor and an updated autofocusing module, is the Nikon D750 the perfect all-rounder? Callum McInerney-Riley finds out in our Nikon D750 review
Resolution, Dynamic Range and Noise
Nikon D750 review – Resolution, Dynamic Range and Noise
The D750 uses a 24-million-pixel full frame sensor that includes an optical low pass filter, although residual maze-like moiré in the resolution charts indicates that the low-pass filter is relatively weak. This means that in terms of resolution the D750 is similar to the D610 that sits below it in the range, but obviously it can’t deliver as much detail as the 36-million-pixel D810.
Dynamic range is very impressive at low ISOs, which means you can extract lots of detail from deep in the shadows in raw processing, or using the Active D-Lighting controls in JPEG. The camera’s highlight metering mode can help to get the best exposures for raw shooters, by minimising clipping in bright areas of the image.
Image quality is excellent at sensitivities up to ISO 1600, but at higher ISOs it naturally deteriorates. However ISO 3200 and 6400 are absolutely fine for less-critical purposes, especially when carefully-processed from Raw. At the highest ISOs JPEGs suffer from strong colour noise and detail loss, and while better results can be had from Raw, this will usually come at the cost of colour saturation. Overall the D750 is a very strong performer, and bettered only by much more expensive cameras.
The D750 resolved around a maximum 3200 l/ph on our Applied Imaging test chart, which is about what we’d expect for its pixel count. At ISO 6400, the resolution drops only slightly, to around 3000 l/ph. But at higher sensitivities noise reduction inevitably reduces the sharpness, giving approx 2400 l/ph at ISO 51200. This test was shot with the Sigma 105mm f/2.8 macro lens, which we use for all our testing and have in all available fittings, at f/5.6 which is the best performing aperture for the lens.
The D750’s sensor delivers excellent results, on a par with the D810. At ISO 50, the peak dynamic range is 12.9EV, and the sensor is still performing well at ISO 3200 with a range of 9.7EV. This means that the D750 can record lots of detail deep into shadow areas, which can be recovered from raw files or by using Active D-Lighting. It’s still important to avoid highlight clipping though, to reap the full benefits of this impressive dynamic range.
This 3D graph compares the colour shift from the reference colour to the photographed chart: the higher the peak, the greater the shift from the original colour. In the default JPEG colour setting, colours are well rendered across the range, with slightly enhanced greens and notably strong blues. Test images display generally natural colour rendition in standard JPEG mode, with pleasing saturation and contrast; the accentuated blues should be particularly good for scenic shots. Colour settings can of course be adjusted in the Picture Control menu settings.
Both Raw and JPEG images taken from our diorama scene are captured at the full range of ISO settings. The camera is placed in its default setting for JPEG images. Raw images are sharpened and noise reduction applied, to strike the best balance between resolution and noise.
The images above have a resolution of 300ppi and are shown at 100% magnification, reflecting a full-resolution print size.
The D750 produces clean, detailed images up to ISO1600. At ISO 3200 and above chroma noise starts to appear in the JPEGs, especially in shadow regions. However this can be removed in Raw processing with little impact on detail. The penalty, however, is pronounced luminance noise coupled with a loss of colour saturation. Images are still quite useable at ISO 6400, and even at ISO 12800 with careful processing. As we’d expect the extended higher ISO settings come with serious image quality penalties in terms of noise and detail loss.
The grey-card images above are JPEG files shot with the D750’s default noise reduction and colour settings applied. The 300ppi images are shown at 100% magnification to reflect the noise that would be experienced when printing an image at maximum size.
The results show the D750 is almost noise-free up to ISO 400, and still gives impressively clean images at ISO 1600. Noise starts to become obvious at higher settings, and by ISO 12,800 both colour and luminance noise are starting to kick in, with ISO 25,600 and ISO 51,200 a lot worse. However, there will always be situations where the extended settings will obtain shots not otherwise achievable.