Sony Alpha A580 review
Sony A580 Review - Image quality
Unlike the A55's translucent shutter, the Sony Alpha A580 has a standard shutter that lifts out of the way when shooting. As there's no material 'in the way' of the sensor, there should be more available light that reaches it which, theoretically, could mean image quality is even better. In reality the differences between the two models are quite minor, especially when ISO sensitivity is taken into account.
Sony A580 - ISO & Image Noise
The A580 seemed reluctant to jump over the ISO 800 mark in Auto ISO mode, and the results when pushed beyond that comfort zone displayed why; the amount of image noise on display is fairly visible. Fortunately it's less heavy handed than purely turning the tones on display into cartoon-like representations, leaving enough of the grain to make it visible without too much magnification.
Sony A580 - Tone and Exposure
Exposure proved to be impressively even when tested across number of different environments, although there was a slight tendency to favour the darker areas and lose an amount of detail in the highlights, although only marginal, the result were generally balanced.
Tone was again extremely even, although at times a touch too reserved to allow the more eye-catching images to dominate. As a result the flesh tones, although varied and well-represented, were a touch too pale.
Sony A580 - Raw vs JPEG
At close inspection the difference between the Raw and JPEG images is minimal, with the benefits of minimal processing being the major incentive for opting for the larger file type. The tonal range is more subtle and colour cast less aggressive when using Raw, but otherwise you won't lose a huge amount by opting for more file space.