Sony Alpha 7 review – Noise, resolution and sensitivity
These images show 72ppi (100% on a computer screen) sections of images of a resolution chart, captured using the Carl Zeiss 55mm f/2.8 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 at the specified sensitivity setting.
Sharing an identical resolution to the 24.3-million-pixel Nikon D610, it’s no surprise to see the Alpha 7 resolve detail down to the same level. Our test charts reveal that the Alpha 7 is capable of resolving down to 32lpmm (lines per mm), but I would stress that to get the best out of the sensor, one of the Zeiss prime lenses should be used as the 28-70mm OSS lens doesn’t do the sensor justice and lacks ‘bite’.
Both raw and JPEG files display no signs of image noise at lower sensitivities, with excellent levels of detail. Looking at raw files at higher sensitivities, the Alpha 7 performs well when compared alongside files from the Nikon D610. At ISO 3200, while luminance noise is evident, it’s very fine and detail is maintained nicely. Interestingly, the Alpha 7 test images displayed noticeably less chroma noise than those from the D610 at this sensitivity.
Luminance noise at ISO 6400 is still very fine, with a pleasing organic look to it, while chroma noise is still controlled very well. Again, results are better than those from the D610, which loses out with slightly more pronounced chroma noise and not quite the same level of detail.
In terms of JPEGs, the D610 manages to deliver less waxy-looking images at high sensitivities, with files from the Alpha 7 a little too overprocessed for my liking.
