Dynamic range
It is often feared that dynamic range will be a casualty with densely populated sensors, but the Alpha 850 has a range of 12EV, which puts it on a par with most high-end DSLRs.
It is also possible to extract a lot of detail from the shadows with a curves adjustment or by using the Dynamic Range Optimizer (D-RO). There are seven settings available for the D-RO, in addition to ‘off’. In its Standard setting, the D-RO adjusts contrast across the entire image. However, in the Advanced Auto and Advanced Level settings, the camera analyses the scene and brightens parts of the image selectively.
There are five settings available in the Advanced Level option. Using too high a level results in artificially flat images as well as increased noise in shadow areas. Consequently, level five is best reserved for very high contrast situations and I mostly used level three.
Understanding the graph: This graph shows the brightness values recorded by the test camera when it is used to photograph a stepped graduation wedge. The wedge has transmission values in 1⁄2EV steps ranging from 0 to 12EV.
The camera’s exposure is set so the 12EV section in the wedge has a brightness value of 255. Software analysis of the image then determines the recorded brightness values of all the other steps and calculates the camera’s dynamic range.
Gamut
This graphic indicates that the Alpha 850 can reproduce the majority of the Adobe RGB gamut in the red, magenta, purple, blue and cyan areas, but as is often the case it struggles to capture the full subtlety of the range of greens available.
Even the more restricted sRGB gamut is slightly clipped in the green area.
