In terms of general performance, the 550UZ acquits itself reasonably well. It starts up in a fraction over three seconds, which isn’t bad considering the size of that zoom lens, and takes nearly as long to shut down again. The AF system is a little on the slow side, and takes over a second to lock on even in good light, but fortunately it doesn’t get much slower at long zoom settings. It is a little slower in very low light, but thanks to a good powerful AF assist lamp it will focus in the dark at a range of several metres.
Shot-to-shot times are reasonable, although I’ve seen a lot better. In the highest quality setting (SHQ) with file sizes of around 3.6MB it can shoot three frames in 4.5 seconds, but then has to pause to write to the memory card. In the slightly lower quality HQ mode, which produces files of around 1.1MB, it can shoot at one frame every 1.5 seconds until the card is full. The video mode is also competent, shooting at 640x480 and 30fps with mono audio. The zoom lens can be used when shooting video, although only if silent mode (no recorded soundtrack) is selected.
Since the 550UZ runs on four AA batteries their duration will obviously depend on the type and brand that are used, but I took well over 200 shots on the set of standard Panasonic alkaline cells that were supplied with the camera and the battery level indicator was still reading full. Considering the amount of glass the focusing and zoom motors have to move around that’s quite a respectable performance.
Finally we come to image quality, and here I will admit to being slightly disappointed, although given the camera’s impressive specification perhaps I was expecting too much. For some reason Olympus has decided to give the 550UZ a tiny 1/2.5in sensor, and I can’t help but think that this was a wasted opportunity. A larger 1/1.8in sensor might have given it better colour depth and dynamic range, and probably better noise control as well. As it stands however, at 50 and 100 ISO quality is very good, with excellent sharpness and detail, but at 400 and over there is colour speckling and image noise plainly visible in all shots. 3200 and 5000 ISO are only available in HQ quality mode, which is selected automatically when these ISO settings are chosen, but the noise reduction system is very heavy-handed, and shots at these speeds lack fine detail, although they have less colour noise than ISO 1600 shots.
The exposure system, as is usually the case with Olympus cameras, performs extremely well, and high contrast shots seldom lose both highlight and shadow detail, although it’s sometimes a close thing.
The lens performs reasonably well, with good corner sharpness at all focal lengths, but at the widest setting it does produce very noticeable barrel distortion, while the longest telephoto setting has the opposite problem, pincushion distortion that makes the horizon curve upwards at the edges of the frame. There was also visible chromatic aberration at both ends of the zoom range, as well as the dreaded purple fringes around high-contrast highlights.
The massive zoom range and impressive image stabilisation make the SP-550UZ a camera with unique capabilities, and at low ISO settings the image quality is very good. Handling, build quality, style and low-light performance are also highlights. The range of manual options and RAW mode will appeal to experienced users, while the beginner-friendly Guide mode is a boon for those keen to learn. However slow focusing and shot-to-shot times, high-ISO image noise and lens distortion at both ends of the zoom range are serious handicaps.