Overall, the S2550's photo quality is OK, but it clearly worsens in images shot higher than ISO 200 and it gets pretty unusable at ISO 800. Like most compact cameras, you'll get good results in bright lighting and outdoors. At ISO 200, there's a noticeable increase in smearing from noise reduction, which can be seen in prints larger than 4x6 inches and at larger sizes on screen. Some post-shoot sharpening helps this, but if you tend to do a lot of heavy cropping or enlarging, it might not be good enough. At ISO 400, fine detail is wiped out making subjects soft and smeary. Again, at small sizes you may not notice, but there's a marked increase in color noise that actually is fairly visible. From there, the camera's photo quality dramatically declines. The loss of detail is one thing, but really it's the color noise that drags it down. Keep in mind that as the lens is extended, the apertures get smaller. To compensate, the camera will raise the ISO or slow the shutter speed if needed. Either way, if you're holding the camera and using its 18x zoom and there's not a lot of light, you're going to end up with soft or blurry photos. But that goes for any megazoom camera, not just the S2550.