In terms of performance, the FX100 comfortably above average. It starts up in just under three seconds, which is fairly quick, and shuts down again in just over two seconds. In single-shot mode it can take a photo every 1.5 seconds, which is faster than most, while in continuous mode it shoots at a very brisk 0.7 seconds per shot. It also has a burst mode which can shoot three frames in about 1.5 seconds. The autofocus system is exceptionally fast and generally accurate, although in wide-area mode I did find that it had a tendency to focus on the background rather than the foreground subject, especially at close range. However it operates extremely well in low light, focusing in a dimly-lit bar with no appreciable delay. It has an AF assist lamp, so it can focus in darkness at a range of several metres.
The 12-megapixel sensor produces large image files. In the highest quality setting, file sizes average about 5MB each, which indicates quite a low compression setting. This is great for picture quality, but it does mean that a 1GB memory card is only enough storage for 163 shots. The lower quality setting increases this to 324 shots, but if you're going to go to the expense of buying a 12MP camera, surely you want to get the best possible quality out of it. One area of performance where the FX100 does stand out is battery duration. It is powered by a large 1150mAh Li-ion battery, one of the highest capacities I've ever seen in a compact camera. Panasonic claim 320 shots on a full charge, and I have no reason to doubt this.
As always, we finally come to the crunch; picture quality. Here there is both good news and bad. The good news is that the combination of a 12MP sensor and a very high quality lens produces some of the most detailed shots I've ever seen from a compact, rivalling the performance of some digital SLRs. The bad news is that Panasonic still hasn't managed to crack its recurring image noise problem, and here the 12MP sensor just makes it worse. There is image noise visible in shots even at the minimum setting of 80 ISO, and at 400 ISO it is bad enough to cause serious colour rendition problems. The noise reduction is quite heavy-handed, reducing fine detail in many shots. This can be adjusted in the menu, but turning it down just means that the shot gets even more noisy. As well as this, there is a general lack of dynamic range, with both burned out highlights and murky shadows on many shots. Under ideal conditions, the FX100 is capable of producing good images, with excellent colour reproduction and loads of detail, and the 28mm wide angle end is genuinely useful, but the extra resolution just isn't worth the reduction in versatility. My advice? If you want a Panasonic compact, buy an FX33 instead.
The Panasonic Lumix FX100 is a difficult camera. While it has excellent build quality, good performance and an exceptionally fine lens, its usefulness is limited by image noise problems. As it is it is hard to recommend it over the slightly cheaper FX33 (or even the FX55), which has a very similar range of features, better image quality and a lower price.