While Sony’s 24.3-million-pixel, full-frame Alpha 99 has a glittering specification on paper, the true test is how the camera handles a number of demanding situations in the field. Read the Sony Alpha 99 review...
Sony Alpha 99 review – Noise, resolution and sensitivity
These images show 72ppi (100% on a computer screen) sections of images of a resolution chart, captured using the fixed Carl Zeiss 24-70mm 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 is at the specified sensitivity setting.
Unsurprisingly, when compared to the Alpha 77 with the same pixel count, resolved detail in the Alpha 99 is equal in good-contrast light at ISO 100 – up to the 32 marker on our resolution charts. There is a significant improvement in the low-light performance of the Alpha 99, though, and the camera can still resolve up to the 26 marker at its ISO 25,600 setting. In fact, the sensitivity range is wider at 9EV to 81⁄3EV, where the Alpha 77’s maximum setting is ISO 16,000.
I am interested to see if the Alpha 99’s low-light performance matches the Cyber-shot DSC-RX1, which uses the same full-frame sensor but is a mirrorless camera without the 1/3EV light loss that occurs with a fixed translucent mirror. In a similar comparison with the Alpha 77 SLT camera and the mirrorless Sony NEX-7, the NEX-7 performs better in low light.
Although the camera scores well on our charts, JPEG files shot at ISO 3200 and above are not especially crisp. When viewed at 100% they are mushy, with chroma noise evident as well as the expected luminance noise. Raw files are sharper, though, so it is definitely worth using raw capture, especially in low-contrast light.