Zoom
A unique zoom range of 18x optical that starts at 28mm and extends to 100x total zoom with its 5.6x digital zoom.

28mm	504mm	5.6x Digital Zoom

The Olympus SP-550 UZ zooms over the equivalent of a 28-504mm range, uniquely wide even among long zooms. Overall performance is good, with some softness at wide angle that responds well to unsharp mask in Photoshop. Chromatic aberration is pretty dramatic at telephoto, but that's to be expected. The 5.6x digital zoom takes it out to 100x total zoom, or 2,822mm equivalent. Results at the maximum digital zoom setting, however, are pretty soft. You do better to restrict the digital zoom to about 2x.

Macro
A below average standard macro area, with noticeable blurring in the corners. Super Macro is excellent. Both macro modes are too close for the flash.

Standard Macro	Macro with Flash	Super Macro with Flash

The Olympus SP-550's macro setting captures a small minimum area of only 3.71 x 2.78 inches (94 x 71 millimeters). This is below average, and details are soft in the corners of the frame. Most cameras have some softening in the corners in macro mode (evidence of the optical "curvature of field" characteristic). At Super Macro, the SP-550 captures an area 1.0 x 0.75 inches (25 x 19mm), an excellent result.

The SP-550's flash had trouble throttling down for the macro area and was partially blocked as well, resulting in a very uneven exposure. (Plan on using external lighting for any macro shots with the SP-550.)

Distortion
Average barrel distortion among long zooms, higher than average pincushion.

Barrel distortion at 28mm is 0.9%

Pincushion at 504mm is 0.5%

This is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide angle) or inward (like a pincushion -- usually at telephoto). The Olympus SP-550's 0.9% barrel distortion at wide angle is higher than average among the cameras we've tested (but its 28mm setting is wider than most), and not noticeable in most images. At the telephoto end, the SP-550 UZ showed higher than average pincushion at 0.5% -- but this isn't surprising, since its telephoto focal length is well beyond average.

Chromatic aberration
Noticeable at wide angle, dramatic at telephoto.

Wide: noticeable but low, top left @ 200%	Wide: noticeable but low, top right @ 200%
Tele: fairly pronounced, top left @200%	Tele: fairly pronounced, top right @200%

Chromatic aberration is noticeable at wide angle, showing several pixels of medium coloration on either side of the target lines. Chromatic aberration becomes quite dramatic at telephoto focal lengths, covering a wider area with brighter coloration. This will show up in printed photographs. (This distortion is visible as a colored fringe around the objects at the edges of the field of view on the resolution target.)

Corner Sharpness
Softening in the corners of the frame, strongest effect in the upper left corner.

Wide: soft in the upper left corner.	Wide: sharp at the center (note evidence of edge enhancement)
Tele: soft in the upper left corner.	Tele: sharp at the center.

The SP-550 UZ produced soft corners at wide angle, the upper right corner showing the most significant effect. This is actually a surprisingly good result, considering the extreme range of this 18x lens. Note sharpening artifacts in the center wide angle shot, appearing as bright halos around the black objects in the frame.

Coverage
The electronic viewfinder and LCD monitor were identical and both very accurate.

28mm eq., Electronic viewfinder	504mm eq., Electronic viewfinder
28mm eq., LCD monitor	504mm eq., LCD monitor

Both the SP-550's electronic viewfinder and LCD were quite accurate, showing nearly 100% frame accuracy at both wide angle (101.8%) and telephoto (97.4%) lens settings.