Casio EX-FH20 Optics

Zoom
Outstanding 20x optical zoom range, with good overall performance, but some softness and chromatic aberration in the corners. Good digital zoom performance as well, with better than average detail.

The Casio High Speed EXILIM EX-FH20's optical zoom range covers the equivalent of a 26-520mm zoom on a 35mm camera, which makes it a real stand out among consumer digital cameras. Results are good at full wide angle, though with a fair bit of blurring in the corners, and some noticeable coma distortion in the foliage against the sky. At full telephoto, details are sharper, but there's some strong chromatic aberration along the high contrast areas close to the edges of the frame. The camera's digital zoom also performed well despite some losses in detail and resolution. Good results overall.

Macro
A very small macro area, though strong lens distortion and an uneven exposure.

The Casio FH20's macro setting captured a tiny minimum area of just 1.04 x 0.78 inches (26 x 20 millimeters), which is exceptionally small. Detail and resolution were pretty good at the center of the frame, but blurring in the corners of the frame was fairly strong. (Most cameras have some softening in the corners in macro mode.) There's also a lot of chromatic aberration to be seen in the frame, particularly in the coin and dollar bill details. Exposure with external lighting was fairly uneven, with strong overexposure along the left side of the frame. (The FH20 focuses so close to the front of the lens that it can be difficult getting light onto the subject: You're left with a very small gap between the lens barrel and subject, through which to shine the light.) The EX-FH20's flash was unusable at this close range, so plan on using external lighting for your closest macro shots with the camera.

Distortion
Average barrel distortion, but high pincushion. (Not surprising for a 20x zoom lens, though.)

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 Casio EXILIM EX-FH20's 0.7% barrel distortion at wide angle is actually about average, compared to most digital cameras, though I personally find this level a little high. (Keep in mind, however, that the EX-FH20's maximum wide angle setting is equivalent to a 26mm lens, wider than most cameras can manage.) At the telephoto end, the camera's 0.5% pincushion distortion is higher than average (though the maximum telephoto is a whopping 520mm equivalent).

Chromatic aberration
Moderate to high level at wide angle, much stronger and brighter distortion at telephoto.

Chromatic aberration is moderate to high at wide angle, showing a good-sized fringe of coloration on either side of the target lines. At telephoto, the distortion is much stronger, with very wide areas of bright coloration that are easily visible in 8x10 inch prints. (This distortion is visible as a slight colored fringe around the objects at the edges of the field of view on the resolution target.) This effect is noticeable in many of the Casio EXILIM EX-FH20's images.

Corner Sharpness
Fairly strong blurring in the corners of the frame at both zoom settings.

The Casio High Speed EXILIM EX-FH20 produced fairly strong blurring in the corners of the frame at full wide angle and telephoto when compared to the center. At full telephoto, target marks at the center of the frame were also just a little softer than average.