Sony SLT-A55 Digital Camera Review

Chromatic Aberration

The images shot by this camera were generally pretty sharp, although the images were somewhat softer when the aperture was stopped down all the way to the f/22 or f/36 maximum of the lens. At more open apertures, the images were pretty sharp across the frame, with only a slight falloff at the edges. From our tests, the sharpest images are captured when this lens is in the middle of the aperture range at about f/13 to f/14.

In the widest zoom setting, the best performance from this lens comes in the middle of the aperture range: the images captured at f/13 are sharper and more clearly defined than the others.

In the middle of the zoom range, once again, the best performance comes from the middle aperture setting, although the widest aperture is also pretty good. The smallest aperture is extremely soft.

At the longest zoom setting that this camera offers, the sharpness is acceptable at the widest and mid apertures, but the image gets extremely soft at the smallest aperture of f/36. One important thing to remember here is that this test is very dependent on the lens, and it seems that the 18-55mm zoom lens that Sony bundles with this camera is not particularly great. We don't test with other lenses, but it seems that the camera is capable of much better performance with a higher quality lens.

Distortion

The 18-55mm SAM lens that comes with the SLT-A55 is biased more towards the wide end of the zoom range, and this seems to have something of a price: the lens introduces a lot of distortion at the wide angle setting: 3.29 per cent barrel distortion, where straight lines become curved inwards towards the center of the image. This distortion was much less at the middle of the zoom range and was barely noticeable at the 55mm setting, though, so you should stick with this end of the zoom if you want straight lines and undistorted faces in your photos.