Pentax A10 Optics

Zoom
A typical 3x optical zoom range, though good performance from the lens. Digital zoom performs about average, with loss of fine detail and resolution.

The Pentax Optio A10 optical zoom range is equivalent to a 38-114mm zoom on a 35mm camera, which is about average for a consumer digital camera. Results were quite good at wide angle, with minimal corner softness and coma distortion visible. As you might expect, the 4x digital zoom resulted in compromised image quality and resolution, and decreased definition in the fine details.

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

The Pentax Optio A10's normal macro setting performed well, capturing a small minimum area of 2.80 x 2.10 inches (71 x 53 millimeters). In Super Macro mode, the minimum area was just a bit smaller, measuring 2.29 x 1.72 inches (58 x 44 millimeters). Detail and resolution were good in both shots, though the standard macro shot had considerably more softening in the corners from the lens. (Most cameras have some softening in the corners in macro mode.) The flash produced an uneven exposure here, with a slight shadow in the lower portion of the frame and a hot spot on and around the brooch. Still, the flash is fairly usable, just plan on using external lighting for more even results here.

Distortion
Moderate barrel distortion at wide angle, still a small amount 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 Pentax Optio A10's 0.8% barrel distortion at wide angle is about average among the cameras we've tested, although still higher than we'd like to see and noticeable in its images. At the telephoto end, the Optio A10 produced about 0.2% barrel distortion, somewhat more than average.

Chromatic aberration
High at wide angle, much less visible at telephoto.

Chromatic aberration is pretty high at wide angle, showing about 12-15 pixels of very bright coloration on either side of the target lines, depending on where you look. The effect is strongest in the upper left corner, though possibly because of some corner softening there. At telephoto, the number of pixels decreases, as does the brightness level. (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
Slight softening in the corners of the frame, strongest effect at telephoto.

The Pentax Optio A10 did soften corners in some cases, with the most notable instance in the lower right corner at full telephoto. However, in the same shot, the other corners of the frame are markedly sharper. At wide angle, some softening occurred in the upper left corner, though results were better throughout the rest of the frame. Overall corner sharpness is better than we're accustomed to seeing from digicams, particularly compact models.

Coverage
Excellent accuracy with LCD monitor.

The Pentax Optio A10's LCD monitor proved quite accurate, showing about 101% frame accuracy at both zoom settings. This is actually just a little loose, as the outline edges are just out of frame. Still very good results.