Just below, the Sony Alpha A100 is compared to its closest competitor, the Pentax K10D. The top row presents the overall scene at ISO 100. Below that are 100% scale crops taken from full-resolution images at each ISO setting from its respective camera. These shots were taken during the day using program mode with no exposure compensation and set ISO sensitivity.

The Sony Alpha A100 shows low noise levels below ISO 400. At ISO 400, noise become noticeable at 100% but has little effect on image details. ISO 800 and 1600 images from the A100 show increased noise and reduced details. This is where the performance of the Alpha A100 is below that of the average DSLR.

The most noticeable difference between the A100 and K10D shots is the different exposure. Since the scene below is very contrasty, neither camera can capture its entire dynamic range. The result is that the Alpha A100 chose to expose more conservatively than the K10D to preserve more details in the highlights on the glass bottles. The difference is about 2-stops, which is quite significant. It is important to mention that during testing there we also cases when the K10D produced a darker exposure than the A100.

In terms of noise levels, it can be seen that the A100 produces noticeably more noise at ISO 800 and 1600. There is also a softening of details starting at ISO 400, although it is not as pronounced as with the night ISO shots. Overall, results from the A100 are very usable until ISO 400. Higher ISO settings should be reserved for small prints.