There are a couple of unusual features. One is the LED light mounted on the front next to the flash. Unlike most AF assist lamps, this one has to be switched on manually, and is bright white rather than the usual near-IR red LEDs used by most other cameras. However it does have the advantage that it can be switched on independently of the camera, so it can be used as a torch. Given that the 790 SW is aimed at outdoor enthusiasts this is a very useful feature. The other unusual feature is something called Fine Zoom, which is found in the main menu. It is yet another variation on our old friend Digital Zoom. It simply enlarges the centre section of the sensor image to give the illusion of extended optical zoom, but at greatly reduced image quality.
The camera's overall performance is actually very good. Thanks to the non-extending zoom lens it starts up very quickly in under 1.5 seconds and shuts down again even more quickly. In single-shot mode at maximum image quality it can shoot once every 2.2 seconds, which is toward the faster end of average, while in continuous shooting mode it can shoot at approximately one frame a second. The specification sheet for the camera states that it can only manage 1.1fps for three frames, but I found that using the faster xD Picture card Type H it was able to maintain 1fps until the card was full. Likewise the 3MP-only high-speed continuous mode was able to maintain 3.5fps indefinitely using a Type H card, instead of being limited to an 11-frame burst with the larger but slower Type M cards.
The AF system is a big improvement over some earlier Olympus models, and focuses very quickly and reliably in good light. It slows down a bit in reduced light, taking about a second to lock on, but it will focus reliably in a dimly-lit room, and the manually-activated AF lamp/torch is bright enough for reliable focussing at a range of about five metres in the dark. In fact it is even bright enough to light the photo, handy if you don't want to use the flash. Olympus' Bright Capture technology, which enhances the monitor view in reduced light, makes low light shooting much easier.
I was somewhat disappointed by the image quality of the previous mju SW models, but fortunately there seems to have been a dramatic improvement in this area for the 790. The lens appears to be the same 10-element f/3.5 - 5.0 unit used on the 770 SW and 725 SW, but here it produces noticeably less barrel distortion at the wide-angle end, in fact virtually none at all. It does still suffer from slight corner softness, but the centre detail is excellent. Overall image quality is among the best I've seen from a 7MP camera, with superb colour rendition, extremely good exposure metering and good dynamic range. In SHQ mode JPEG files average around 2.5MB, which is a little on the small side, but there were few compression artefacts visible. In the default HQ mode the files are around 1.5MB, but there are noticeable artefacts in plain colour areas. Noise control isn't perfect, but it is about average for a small-sensor compact, with usable image quality at 400 ISO, and just about passable at 800 if you're not too fussy. All in all a good performance, and a camera that will not disappoint any adrenaline-junkies who buy it.
The Olympus mju 790 SW is a welcome return to form for a series that has seen some image quality and performance problems. It offers a simple specification and basic feature set for the price, but apart from the disappointing video mode it performs well and is capable of taking high quality pictures in situations that would defeat most other cameras. If you're looking for a stylish compact that you can take almost anywhere, the 790 SW is the ideal choice.