Sony DSC-T77 Optics

Zoom
A fairly standard 4x optical zoom lens, about average for the subcompact camera category. Better than average performance with the digital zoom.

The Sony Cyber-shot DSC-T77's 4x optical zoom lens covers a range equivalent to a 35-140mm zoom on a 35mm camera, slightly more than the 3x you typically find in subcompact cameras like the T77. At full wide-angle, detail is pretty good at the center of the frame, though some blurring is noticeable in the corners (strongest in the top corners). There's also a small amount of coma distortion around the leaves against the sky, and a little chromatic aberration visible in areas of high contrast. At full telephoto, blurring is less visible in the corners of the frame, and only a little chromatic aberration is still present around the white trim on the house. The camera's 2x digital zoom did a good job of preserving detail despite the digital enlargement. Subcompact cameras tend to sacrifice optical quality for compactness, a factor that is at work here, but performance is good for standard snapshots.

Macro
A very small macro area with good detail and high resolution at the center of the frame. Flash performance is better than average this close, but still uneven.

The Sony Cyber-shot DSC-T77's macro setting performed well, capturing a minimum area of only 0.94 x 0.70 inches (24 x 18 millimeters). Detail and resolution were both very good at the center of the frame, with good definition in the fibers of the dollar bill. The corners get a little blurred, though, losing some of the fine details. Most cameras have some softening in the corners in macro mode, especially sub-compacts: The Sony T77 really outperforms its class in this shot. The DSC-T77's flash throttled down fairly well for the macro area, though the exposure is uneven with shadows in the corners.

Distortion
About average barrel distortion at wide angle, high pincushion at telephoto.

The Sony Cyber-shot DSC-T77's 0.8% barrel distortion at wide angle is actually average compared to other consumer digital cameras, though that's still more distortion than the editors here at IR like to see. At the telephoto end, the DSC-T77's 0.6% pincushion distortion is much higher than average, and quite noticeable in its telephoto images. 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
Moderate levels at both wide angle, a bit less at telephoto, though with bright coloration at each setting.

Chromatic aberration is moderate at wide angle, but a bit lower at telephoto. These days, we're using 8x10-inch prints as the metric by which to gauge chromatic aberration, since high-megapixel cameras render direct pixel-peeping less significant to the average user. Looking at prints from the Sony T77, we can easily see thin colored fringes on high-contrast elements near the edges of the frame, extending perhaps 30% of the way toward the center of the image. They're definitely visible, but also far from the worst we've seen: Overall, a good performance for a subcompact camera. (This distortion is visible as a slight colored fringe around the objects at the edges of the field of view on the resolution target.) Effects are noticeable in several of the DSC-T77's images, especially around areas of high contrast.

Corner Sharpness
Stronger blurring in the corners at full wide angle, with a modest amount at full telephoto.

The Sony Cyber-shot DSC-T77 produced soft corners of the frame at full wide-angle, with the strongest blurring in the upper left corner as compared to the center of the frame. The lower right corner was quite sharp, suggesting that the sensor chip on our sample is slightly tilted. (Unfortunately, a common occurrence with digicams.) At full telephoto, blurring was much less in the corners of the frame, with the strongest instance in the lower right corner. Again, the Sony T77 did better than average for a subcompact camera.

Coverage
Very good accuracy from the LCD monitor.

The Sony Cyber-shot DSC-T77's LCD monitor showed about 103% coverage accuracy at wide angle, and about 99% at telephoto. Great results overall, the inaccuracy seen is really just the effect of barrel and pincushion distortion bending the target lines out of or into the frame.