Canon SD800 IS Optics

Zoom
An unusual 3.8x optical zoom range that starts at 28mm, with good performance.

The Canon PowerShot SD800 IS zooms over the equivalent of a 28-105mm range, which is atypical for its class, offering greater wide angle than most small digicams. Overall performance is quite good, with good detail and sharpness at wide angle. The 4x Precision Digital zoom takes it out to 15x total, with the typical loss of resolution associated with Digital Zoom, although the SD800 IS arguably does a better than average job.

Macro
A very small macro area, but noticeable blurring in the corners. Closest focusing distance is too close for the flash.

The Canon PowerShot SD800's macro setting captures a small minimum area of only 1.54 x 1.15 inches (39 x 29 millimeters). While the macro area is quite small, 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).

The SD800'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 SD800.)

Distortion
Average barrel distortion at wide-angle, no pincushion at telephoto.

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 SD800's 0.91% barrel distortion at wide angle is 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 SD800 showed no measurable distortion at all.

Chromatic aberration
Noticeable at wide angle (but small effect on images at edges, none at telephoto.

Chromatic aberration is noticable at wide angle, showing several pixels of medium coloration on either side of the target lines, but decreases to very low levels at telephoto focal lengths. (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
Some softening in the corners of the frame, strongest effect in the lower right corner.

The SD800 IS produced soft corners at wide angle, the lower right corner showing the most significant effect. This is very common at wide angle in small cameras like this, and most comparable cameras don't have a 28mm wide angle setting. Telephoto performance is much improved, only mildly softer than the center shot.

Coverage
Optical viewfinder is tight and skewed to the top. Excellent accuracy from the LCD monitor.

The SD800's optical viewfinder was quite tight, showing under 80% frame accuracy at both wide angle (78%) and telephoto (76%) lens settings. However, the LCD monitor showed at least 100% accuracy at both wide (103%) and telephoto (100%).