Like most of Casio's cameras, the Z77 is a brisk performer. It starts up in under two seconds, and in single-shot mode it can take a picture every 1.7 seconds, focusing for every shot, which is pretty good. In normal speed continuous mode it manages a bit over a frame a second. It has a high-speed continuous mode which can shoot at three frames a second, but it is limited to 2-megapixel resolution. There is also a flash burst mode which can take three shots with flash in about a second. Also like most previous Exilim cameras, the Z77 has a very fast and accurate AF system, and it works very well in reduced light too. It has no AF assist lamp, but I was able to take good sharp photos in a dimly-lit club without too much trouble. The built-in flash is reasonably strong with a range of 3.5m at 200 ISO, with good frame coverage and exposure. Battery duration is also pretty good at 190 shots, especially considering the wafer-thin dimensions of the 700mAh Li-ion rechargeable.
Unfortunately the Z77 does have one major weakness, and that is its final image quality. It's "only" a 7.2-megapixel model, so it's not going to be able to match more powerful rivals for total resolution, but its main problem its lens quality. The ultra-compact folding lens suffers from significant barrel distortion at the wide-angle end, and pincushion distortion at the telephoto end, but it is overall sharpness that is the real problem. It's not too bad in the centre of the frame, but it gets very soft toward the edges, and also suffers from some chromatic aberration. Image noise isn't too much of a problem, mainly because the Z77 is limited to a maximum of 800 ISO. At the lowest setting images are nice and clean, but above 200 ISO noise does become very noticeable.
If you're looking for a cheap, slim, stylish camera for general snapshots the Casio Exilim EX-Z77 has a lot in its favour. It is well made, easy to use, looks good and has good fast performance. It has an excellent autofocus system and works well in low light despite its lack of an assist lamp. The only real drawback is overall image quality, especially considering the results from some of its rivals. However on value for money it's hard to beat.