Sony Alpha A55 review
Sony Alpha A55 review - Image Quality
Sony A55 review - Tone & Exposure
Despite only 70% of available light reaching the sensor there's no discernable difference in image quality compared to a DSLR with a similar sensor size and resolution. The loss of 30% of light only equates to 1/3rd of a stop and the processing adjusts for this accordingly so that the output is still in accordance with the same ISO standard.
Sony Alpha A55 review test sample image - click for full size gallery
Exposure is generally accurate and avoids overexposure in most situations. However there is an issue with ghosting that, despite only affecting a tiny percentage of images, does need pointing out. Ghosting gets its name from a secondary, ghost-like image that can appear within a single frame. In the case of the A55 this is not at all severe and only clipped-out (overexposed) highlight areas of a considerably small size will show a ghost in very close proximity. There are very few cases when this will be a problem as the highlight area needs to be limited to the equivalent of a few pixels to show, though the issue is still there.
Tonally images on the camera's LCD screen appear more punchy and vibrant than when revealed on a computer screen.
Sony A55 review - Colour & White Balance
Auto White Balance works well, despite the occasional outdoor cool cast and indoor warm cast. Colour itself appears more punchy when viewed on the camera's LCD, but lacks quite the same level of contrast when viewed on a computer screen. There is also a slight colour shift between the LCD and a balanced monitor.
For further control there are a variety of Creative Style options to chose from that include: Vivid, Sunset, Portrait and Black & White.
Sony A55 review - Sharpness & Detail
The A55 resolves detail well at lower ISO settings, but at higher ISO sensitivities detail can be lacking. The 18-55mm kit lens performs adequately enough, although better quality lenses (such as the 50mm f/1.4 Sigma we used) will obviously yield better results.
Sony A55 review - RAW vs JPEG
In the box is a copy of Sony's Image Data Converter SR software that can be used to convert the ARW-format Raw files.
The difference between ARW and JPEG is negligible at first glance, but the lack of noise reduction employed in the Raw file means more overall detail. This becomes progressively more noticeable from ISO 800 and upwards, and is particularly prominent at the highest sensitivities.
Sony A55 review - ISO Quality & Image Noise
Image noise is no problem when shooting ISO 100-400, but begins to appear from ISO 800 onwards. Between ISO 800-1600, images are still of a good quality but detail does begins to diminish - especially when viewing images at 100%.
Sony Alpha review test sample image - click for full size gallery and full ISO range
ISO 3200 is still usable, and although 6400-12,800 show a considerable loss of detail and the presence of luminance noise, the A55's noise reduction processing does a good job of keeping colour noise at bay, even in the shadow areas.