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

28mm	105mm	4x Digital Zoom

The Canon PowerShot SD870 IS features an optical zoom covering the equivalent of a 28-105mm range, wider than the average consumer digital camera. Some corner softness and coma distortion were present at full wide angle, but only very far into the corner. Overall results were quite good, with fairly sharp details. The camera's 4x digital zoom did a pretty good job, despite the fuzzy details in the finer areas. Though resolution and quality are compromised in the digital zoom, results aren't too bad for a 4x digital enlargement.

Macro
A small macro area with excellent detail and high resolution. Flash exposure was very uneven up close though.

Standard Macro	Macro with Flash

The Canon SD870 IS's macro setting performed well, capturing a small minimum area of 1.62 x 1.22 inches (41 x 31 millimeters). Detail and resolution were both excellent though, with a moderate amount of softening in the corners from the lens. Chromatic aberration is the only real fault here, but it's not too noticeable unless you're looking for it. (Most cameras have some softening in the corners in macro mode, but the Canon SD870 IS actually performs pretty well here.) At such close shooting range, the Canon SD870 IS' 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 with your closest shots.)

Distortion
High barrel distortion at wide angle, but practically no distortion at telephoto.

Barrel distortion at 28mm is 1.1%

Barrel distortion at 105mm is less than 0.1%

The Canon PowerShot SD870 IS's 1.1% barrel distortion at wide angle is higher than average among the cameras we've tested, though not unexpected for the Canon SD870's wider-than-average 28mm equivalent zoom setting. The effect is quite noticeable in some of our test shots. At the telephoto end, the Canon SD870 IS actually produced a tiny amount of barrel distortion, about one pixel, less than 0.1%. 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).

Chromatic aberration
High and noticeable at wide angle, almost none at telephoto.

Wide: High and bright, top left @ 200%	Wide: High and bright, top right @ 200%
Tele: Very low, top left @200%	Tele: Very low, top right @200%

The Canon SD870's chromatic aberration is rather high at wide angle, showing 10+ pixels of bright coloration on either side of the target lines, which is exacerbated by corner softness. The effect is pretty noticeable in several of our wide angle test shots. At telephoto, the effect is quite low and not very noticeable. (This distortion is visible as a very slight colored fringe around the objects at the edges of the field of view on the resolution target.)

Corner Sharpness
Strong blurring in the corners at wide angle, though much better performance at telephoto. Worst blurring is restricted to the extreme corners though.

Wide: Very soft in the corners (upper left)	Wide: Sharp at center
Tele: Quite sharp in the corners (upper left)	Tele: Sharp at center

Our sample of the Canon PowerShot SD870 IS produced very soft corners at wide angle, with the strongest effect in the upper corners. However, at telephoto, blurring was minimal in the corners compared to the center of the frame, and even at wide angle, the blurring didn't extend very far into the frame.

Coverage
Very good accuracy with the LCD monitor.

28mm eq., LCD	105mm eq., LCD

The Canon PowerShot SD870 IS's LCD viewfinder was quite accurate, showing about 102% accuracy at wide angle and about 100% at telephoto. The SD870 IS unfortunately does not have an optical viewfinder, which is useful in bright sunshine when LCD monitors can be difficult to see, or to conserve battery life; the good news is that the LCD is very usable in direct sunlight.