Noise, Resolution & Sensitivity
These 100% enlargements show how the 16-50mm f/2.8 lens is slightly sharper than the 18-55mm f/3.5-5.6 kit lens
With the same imaging sensor and fixed mirror as the Alpha 77, it comes as no surprise that the Alpha 65 delivers superb image quality. At the base ISO setting, the Alpha 65 reaches the 30 marker on our resolution charts.
In fact, the resolution chart results of the Alpha 65 trump many other enthusiast-level cameras. Using the 18-55mm kit lens seems like a waste on a sensor that this good. When using a camera with a fixed mirror, the downside is that less light reaches the imaging sensor.
As we showed in our article Sensor comparisons (AP 30 April 2011), even at base ISO settings there is a degree of luminance noise in Alpha SLT cameras. At the higher ISO ratings of ISO 3200 and above, noise is significantly higher and obvious in real-world images. This is an area where SLT cameras fall short of the DSLR competition.
Despite noise levels being more prominent at higher ISO sensitivities than in its competitors, the Alpha 65 is still able to resolve a lot of detail, reaching the 24 marker at ISO 6400.
These images show 72ppi (100% on a computer screen) sections of images of a resolution chart, captured using a Sigma 105mm 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.