Canon PowerShot G7 Optics
A nice 6x optical zoom range, with excellent performance. Digital zoom also performs well.
|35mm||210mm||4x Digital Zoom|
The Canon G7 optical zoom covers the equivalent of a 35-210mm range, which is quite generous among consumer digital cameras. It is further enhanced by an optical Image Stabilization system. Results at wide angle are excellent, with minimal corner softness and coma distortion. The camera's 4x digital zoom also performed above average. Even though resolution is lower and fine details are fuzzy, overall results are actually better than expected for digital enlargement.
A tiny macro area with good detail. Flash can't make it around lens at this distance.
|Standard Macro||Macro with Flash|
The Canon G7 performed reasonably well in the macro category, capturing a tiny minimum area measuring only 0.98 x 0.74 inches (25 x 19 millimeters). The level of fine detail right in the center is excellent, as even the tiny fibers of the dollar bill are distinct. There's plenty of softness radiating out from the center of the lens, however, strongest on the left side of the frame. (Most cameras have some softening in the corners in macro mode, but this is considerable.) The flash exposure looks good as well, until you look in the upper left corner and see the very bright area. Clearly, the flash is so close to the lens that it casts a shadow over the subject, which the camera compensates for quite well, producing a reasonably well-exposed shot. Draw your own conculsions, but the further you get from your subject, the effect will increase. Better to use external light sources and not shoot this close.
Moderate barrel distortion, and moderately high pincushion.
|Barrel distortion at 35mm is 0.82%|
|Pincushion at 210mm is less than 0.19%|
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 Canon G7 produced about 0.82% barrel distortion at wide angle, which is about average among the cameras we've tested, though still a little high for my preference. At the telephoto end, the lens produced about 0.19% pincushion distortion, which is a little higher than average.
Moderately high aberration at wide angle, but very low distortion at telephoto.
|Wide: moderately high and bright,
top left @ 200%
top right @ 200%
top left @200%
top right @200%
Chromatic aberration is moderately high at the wide angle lens setting, with about 10-11 bright pixels. At telephoto, distortion is much lower, and less bright. 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. However, the effect is less noticable given the camera's high resolution, especially at the usual 8x10 enlargement size. It's obviously a greater factor if you crop to include one of the corners.
Minimal softening in the corners from the Canon G7's lens.
|Wide: just a hint soft in the corners (lower left)||Wide: slightly sharper at center|
|Tele: slightly soft in the
corners (upper right)
|Tele: sharper at center|
The Canon G7's lens produced only slightly soft corners in a few shots, though the effect wasn't strong in its images. At both wide angle and telephoto, corners are just slightly softer than the center of the frame. A very good performance.
A tight optical viewfinder, but very accurate LCD monitor.
|35mm eq., optical viewfinder||210mm eq., optical viewfinder|
|35mm eq., LCD monitor||210mm eq., LCD monitor|
The Canon G7's optical viewfinder was a bit tight, showing only 83% frame accuracy at wide angle, and about 82% at telephoto. You can see in the Telephoto shot (upper right corner) just how dramatic paralax error can become with a 6x zoom on a rangefinder. The LCD monitor was much more accurate, showing a little more than 100% frame accuracy at both zoom settings.