Canon A650 IS Optics

Zoom
A 6x optical zoom lens with very good performance. Digital zoom also performs well.

The Canon PowerShot A650 IS' optical zoom covers the equivalent of a 35-210mm, a much larger range than the average consumer digital camera. Details are reasonably sharp and well-defined at full wide angle, with low levels of coma distortion, chromatic aberration and very good corner-to-corner sharpness. Results at full telephoto are also quite good. The 4x digital zoom performs well, considering how much digital enlargement there is (750K pixels interpolated to 12 million). A very good performance overall.

Macro
A very small macro area but with excessive corner softening. Flash performs well.

The Canon PowerShot A650 IS' macro setting results are a mixed bag. Although it captured a very small minimum area of 1.01 x 0.75 inches (26 x 19 millimeters), overall detail was soft, and there's an excessive amount of corner softening that extends deep into the frame. Most cameras have some softening in the corners in macro mode, but here the softening starts inside the top and bottom of the numeral 1. Note that this is so extremely close -- just two or three millimeters -- that the flash exposure actually appears good because the lens body blocked almost the entire subject (note the overexposed upper left corner). Plan on using external lighting for the very closest macro shots with the A650 IS, and even then, you may have trouble getting the light in onto your subject given how close the A650 IS focuses.

Distortion
Moderate barrel distortion, though low pincushion.

The Canon PowerShot A650 IS' 0.8% barrel distortion at wide angle is about average, though we think this level is too high, as it can be quite evident in photos. At the telephoto end, the A650 IS' 0.2% pincushion distortion is reasonably low, if not the lowest we've seen. 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
Moderately high and bright at wide angle, lower at telephoto. More than we'd like overall, noticeable in some of our images at wide angle.

Chromatic aberration is moderately high at wide angle, showing about 6-8 pixels of bright coloration on either side of the target lines, and it extends fairly far into the frame. At telephoto, the effect isn't quite as strong, as the fringing is not nearly as bright. (This distortion is visible as a slight colored fringe around the objects at the edges of the field of view on the resolution target.)

Corner Sharpness
Very good corner-to-corner sharpness, with only slight blurring visible, and only in one or two corners at both zoom settings.

The Canon PowerShot A650 IS produced good corner-to-corner sharpness at both wide angle and telephoto zoom settings. At both settings, blurring was minor, and only appeared in one (upper left at telephoto) or two (upper and lower left at wide angle) corners of the frame. Very good performance here. (But the colored fringing from chromatic aberration are clearly visible, particularly at wide angle.)

Coverage
A tight optical viewfinder, but accurate LCD monitor.

The Canon PowerShot A650 IS' optical viewfinder proved very tight in its framing, showing only 78% of the final image area at both wide angle and telephoto. The optical viewfinder was offset and slightly tilted with respect to the sensor as well. However, the LCD monitor proved much more accurate, showing about 101% at wide angle, and about 100% at telephoto.