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.
This is a 100 percent crop of the inset photo that was taken at ISO 800. When viewed full size, you can see the color noise throughout. Although its less visible when photos are viewed at smaller sizes, it messes up the overall color in photos.
On the other hand, the camera is capable of capturing some nice photos with good fine detail and sharpness. This is a 100 percent crop of the inset image, which was taken in Macro mode. If you like taking close-ups, the S2550HD can focus as closely as 2.4 inches from a subject.
Its color quality, at least at lower ISOs, is very good. The S2550HD produces well exposed photos with bright, vivid colors that were reasonably close to accurate in our lab tests. White balance could use some fine tuning, though. The presets for indoors had a yellow/green look to them, while the manual white balance had a slight magenta look to it. Oddly, the auto setting performed best, but was still a little yellow.
If you'd like to take more control over your results, the S2550HD does have Aperture-priority, Shutter-priority, and Manual modes. For the most part, though, the real control is over shutter speed with settings from 8 seconds to 1/2,000 second. Apertures are limited to two stops at each step of the zoom range courtesy of an ND filter: f3.1-6.4 wide and f5.6-11 telephoto. There is some depth of field to play with, but don't expect the kind of control you'd get from a digital SLR.
Of course the main attraction is the wide-angle zoom lens--28-504mm on a 35mm camera. The range allows for shooting flexibility, but since the photos generally lack sharpness and fine detail, you won't want to do too much cropping or enlarging. Also, the autofocus is slow at the telephoto end, so trying to shoot a moving subject with this camera is very tricky. Lastly, the sensor-shift image stabilization doesn't seem to be all that helpful, so you'll probably want to put this camera on a stable support when using the zoom to get the sharpest results.
Though it's typical of lower-end (and even higher-end) megazoom cameras, the S2550HD produces a good amount of purple fringing in high-contrast areas of photos, especially at the telephoto end. This is an extreme example; generally it's only visible when photos are viewed at 100 percent. But if you're not careful about what you're shooting, it can be enough to change the color of a photo.
The S2550HD offers several continuous shooting options, the fastest of which is 8 frames per second for up to 20 photos at approximately 3 megapixels. At 100 percent, the photos look more like video grabs than still images, but for Web sharing or small prints they're fine. Still, similar to burst modes on almost all compact cameras, the focus and exposure is taken with the first shot, so if you're moving the camera or the subject moves, you might not get a clean photo.
On the mode dial is a Panorama option. It's an assist-and-stitch type where you use a ghost image of a previous shot on the left of the screen to line up subsequent shots. Once the last of three photos is taken the camera stitches them together. As long as you do a decent job of lining up the shots, the stitching works well and you end up with a nice panorama.