Canon G11 Optics

Zoom
A fairly wide, 5x optical zoom lens with very good performance. Average digital zoom performance.

The Canon PowerShot G11's lens covers the equivalent of a 28-140mm zoom on a 35mm camera, which is slightly more zoom ratio than most consumer digital cameras. While the G11 maintains the same lower 5x zoom ratio that the G10 had relative to the 6x zoom on the G9, we again welcome the gain at the wide-angle end, even at the cost of losing some telephoto reach in the bargain. Results are quite good at wide-angle, with minimal blurring and coma distortion, though some minor chromatic aberration can be seen in the corners and edges, as well as some flare around the brighter areas of the scene. Performance at full telephoto was also very good, with only a small amount of chromatic aberration and flare. The camera's 4x digital zoom did a pretty good job of maintaining fine detail despite the typical blurring and loss of resolution associated with digital zoom.

Macro
A very small macro area, with excellent detail and resolution. Flash is blocked by lens.

The Canon PowerShot G11's macro setting captured a very tiny minimum area of just 1.21 x 0.91 inches (31 x 23 millimeters). Exposure is rather uneven, due to the very close shooting range, and the three dimensional structure of the target (the brooch and one of the coins are shading the dollar bill). Detail and resolution were both excellent, particularly in the center of the frame. There's some softening in the corners from the lens, although it's hard to tell how much, because the lighting is so uneven, as well as some chromatic aberration. (Most cameras have some softening in the corners in macro mode. What we can see here, within the limits defined by the lighting, is about typical) The Canon G11's flash throttled down for the macro area fairly well, but the exposure was again quite uneven, as the flash is blocked by the lens when this close.

The three-dimensional nature of our macro target reveals what might not be evident with the flat targets used by some testers: The Canon G11 does indeed let you get very close to your subject, but the working distance is shorter than average; to the point that it can be difficult getting light onto your subjects. Plan on using external lighting for the closest macro shots with the G11, and even then, you may have trouble enough light in around the lens barrel without blowing out parts of the image. A very good performance, but the short working distance could be a problem with some subjects.

Distortion
Average barrel distortion at wide-angle, very low pincushion at telephoto.

The Canon G11's 0.8% barrel distortion at wide-angle is about average among the cameras we've tested, but that's actually pretty good considering its 28mm equivalent focal length. Still, we'd like to see lower, as this distortion is quite noticeable in some of its images. At the telephoto end, the G11's less than 0.1% pincushion distortion is almost nonexistent. Distortion 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 bright at wide-angle, very low at telephoto.

Chromatic aberration is moderate at wide-angle, showing about 6-8 pixels of moderately bright coloration on either side of the target lines. The color extends a ways into the frame, but the width of the fringes narrows rapidly as you move toward the center, so is less objectionable than it might be otherwise. At telephoto, the extent of the chromatic aberration is about the same, but it's not nearly as bright and therefore much less noticeable. Chromatic aberration is a type of distortion visible as a slight colored fringe around the objects at the edges of the field of view on the resolution target.

Corner Sharpness
Minor blurring in the corners of the frame at wide-angle and telephoto.

The Canon PowerShot G11's lens produced only minor corner softness at full wide-angle and telephoto. Blurring was strongest in the upper left corner, for both wide-angle and telephoto, but didn't extend very far into the frame: By the time you've moved 15% (tele) or 25% (wide-angle) toward the center, the blurring largely disappears. Overall results are very good, especially considering that these shots were taken at maximum aperture, as sharpness generally improves as the lens is stopped down to smaller apertures.

Coverage
A rather inaccurate optical viewfinder, but excellent accuracy from the LCD monitor.

The Canon PowerShot G11's optical viewfinder was very tight, at around 79% coverage at wide-angle and at telephoto. It's also tilted and offset with respect to the CCD. This is not unusual for this type of optical viewfinder, though. The LCD monitor was much more accurate, showing about 100% coverage accuracy at both wide-angle and telephoto.