Casio cameras are well known for their outstanding performance, and the Z85 is no exception. It starts up very quickly in around 1.5 seconds and shuts down again in about the same. In single-shot mode it can capture a picture every 2.2 seconds, which is about average for its class, while in normal continuous shooting mode it can take a shot every 1.2 seconds, which is pretty quick for a sub-£100 camera. It has a flash continuous mode which takes a quick burst of three shots with flash on each shot, and a high-speed continuous mode which can shoot at approximately five frames a second, but this is limited to a resolution of 2MP.
Casio's autofocus system is still one of the fastest on the market, and in most lighting conditions the Z85 will focus in a fraction of a second. It works well even in very dim lighting, but unfortunately the lack of an AF assist lamp means it can't focus once light falls below a certain level, and has major problems in nightclub conditions. If I had to suggest one improvement for the Z85, it would be to add an AF assist lamp, since its lack limits the camera's usefulness in many social situations.
The Z85's only real weak spot is its overall picture quality. It has a number of good points, including reliably accurate exposure, colour reproduction and automatic white balance, and the low compression rate in the high-quality Fine mode produces reassuringly large and artefact-free image files, but unfortunately there are problems with image noise even at the lowest sensitivity setting, which get progressively worse as sensitivity is increased. The maximum sensitivity is only 1600 ISO, which is pretty low by recent standards, but even at this setting it is pushing the boundaries of usability. The lens also has some problems, with significant barrel distortion at wide angle and very poor sharpness towards the edges of the frame.
The Casio Exilim EX-Z85 is close to being the perfect pocket compact. It is incredibly compact, solidly made, very easy to use and has excellent all-round performance. Focusing is quick and accurate, but the lack of an AF lamp limits its usefulness in some situations. Unfortunately it is let down by inferior image quality, especially poor lens performance and image noise problems.