Resolution, noise and sensitivity
These images show 72ppi sections of images of a resolution chart, still-life scene and a grey card. 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.
As the resolution chart images show, the Alpha 850 has the same impressive ability to resolve fine detail as the camera it is based on, the Alpha 900. Thanks to its class-leading pixel count it is able to resolve lines further along our chart than almost all other cameras. This makes the Alpha 850 especially attractive to landscape and macro photographers who want to be able to extract the maximum amount of detail from a scene. It’s just a shame that the camera doesn’t offer a Live View image on the LCD screen, as this would really make it a firm favourite with these photographers.
Although the Alpha 850 has a full-frame sensor, a pixel count of 24.6 million requires very small photosites and noise is therefore an inevitable risk. When the high-sensitivity noise-reduction system is turned off, JPEG files taken at ISO 6400 have the highest level of noise in the red channel that we have measured to date.
The other channels are also pretty noisy at this setting. Despite these high levels, though, I prefer the results captured when the high-sensitivity noise-reduction system is turned off, as the JPEG images are sharper and have more detail. Although images taken at ISO 6400 have plenty of coloured speckling visible, there is no banding in my images and the Extra Fine JPEG files don’t require any post-capture sharpening.
Interestingly, given our laboratory-based noise measurements, which match the results found with the Alpha 900, my images don’t have significantly more red speckling than they do green and blue at ISO 6400.
