The technical DIWA tests are intensive and include a very comprehensive test procedure. A regular feature we include in the camera tests, among other things, is color reproduction measurement compared to the calibrated colors of the Gretag Macbeth Color Checker. There is only a slight deviation measured, which is also relatively consistent, showing a similar value up to the high ISO 3200 sensitivity. Color saturation is standard slightly on the strong side, although that seems a logical choice, since the enthusiast photographer is generally fond of it. Skin tones appear to be slightly warm, yet still come across as quite natural. Moreover, the color saturation can be accurately adjusted in seven stops, so that the serious photographer is still able to go about his business.
Sony Alpha 850 white balance settings
The auto white balance of the A900 encountered some difficulties in handling incandescent light, and reproduction turned out somewhat warm. Frankly, we had expected more accuracy and effectiveness, especially for a professional DSLR camera. The results for the Sony Alpha 850 remained the same as far as white balance is concerned. The auto white balance tends to turn out too warm, so the most effective solution is to use the manual white balance. In addition, the average contrast is somewhat conservative and exposure compensation of 1/3- 1EV stop will improve the picture.
ISO values of the Sony Alpha 850
The Sony Alpha 850 has inherited the image sensor of the A900. This includes a similar ISO range with a maximum setting of ISO 6400. Compared to the competition, where we even come across ISO 25600, Sony is not quite in pace. Perhaps this is Sony's more conservative approach towards this item too. The actual effective sensitivity of the image sensor was tested in the DIWA lab, and it became clear that the ISO 200-1600 is not equal to the specified values in the specifications. With exceptions of more than 30% these are more significant differences than on average.
Sony DSLR-A850 signal/noise ratio
One year after the launch of the Sony A900, a lot has been improved by the industry when it comes to signal / noise ratio and visible noise. High ISO settings of 3200 are applicable more and more often without encountering any problems, and no words are spilled on the quality of noise at low ISO values. In this respect, we had simply hoped for more from the new Sony DSLR-A850. The fact that the camera is almost identical to the A900, made us suspect however that we would not find any revolutionary improvements as far as noise is concerned, and this is proven by the technical DIWA tests.
Up to ISO 400 a lot of detail is visible in the picture, while at ISO 800, we find the effect of the noise reduction working fiercely and detail thus decreases. As for ISO 800 and higher, the quality of the picture really is at stake. From ISO 1600, editing afterwards is required to be able to reach a high print quality. It is certainly possible, but given the current quality and technology at high ISO, the Sony A850 is running behind the competition in terms of signal / noise ratio.
Carl Zeiss Vario-Sonnar T* DT 24-70mm f/2.8 ZA lens
If you want to get the most out of your Sony Alpha 850, you actually have to use the range of ZEISS lenses Sony is offering. Of course there are (cheaper) lenses on this list, which are officially supported, but the majority of those lenses are not able to comply with the high requirements, such as for example the resolution and the full format. The Sony A850 was thoroughly tested in the DIWA Lab in combination with a Carl Zeiss Vario-Sonnar T* DT 24-70mm f/2.8 ZA lens. A lens that performs superbly in terms of sharpness, and it is only at 70mm that the edges show slightly visible blur. The remaining focal lengths provide optimum sharpness for both the edges and the center.
Distortion and chromatic aberration of the lens
Visible distortion (+0.8%) crops up at 24 mm over the entire aperture range, but on the whole it is negligible and does not lead to any quality loss. However, the Carl Zeiss Vario-Sonnar T* DT 24-70mm f/2.8 ZA lens does suffer from significant chromatic aberration. In particular the 24mm wide-angle. In addition, the 70mm telephoto range also suffers from the annoying purple edges around a high contrast subject. The lens, although not unexpectedly, suffers from vignetting at full aperture, f/2.8; in particular at 24 and 70 mm. The chromatic aberration is a pity, while other than that, the lens combines perfectly with a camera like the Alpha 850.