Sony DSC-P1Sony packs a 3 megapixel CCD and a full 3x optical zoom lens into an exceptionally compact digicam!<<Viewfinder :(Previous) | (Next): Exposure & Flash>> Page 5:OpticsReview First Posted: 9/12/2000 |
Optics
The DSC-P1's lens is some of the biggest news about its design, as it packs a full 3x zoom ratio into a very small form factor, yet still manages to cover the 3 megapixel sensor quite well. With a 8 to 24 mm focal length range (equivalent to a 39 to 117 mm lens on a 35 mm camera), we found the P1's lens to be of quite high quality, in terms of its sharpness and freedom from chromatic aberration. We did notice a fair amount of barrel distortion (0.9 percent) at the wide angle setting, as well as some visible "coma" in the corners of the image at that setting as well. Overall though, we felt that Sony did an excellent job of lens design, given the extremely tight dimensions they managed to pack it into.
When the camera is powered on, the lens automatically extends into its operating position. It retracts again when the camera is shut down, and an automatic protective shutter closes over it when it is in the retracted position. Apertures are automatically controlled by the camera, which appears to switch between two fixed aperture settings depending on light level. These fixed apertures correspond to values of f/2.8 and f/5.3 at the wide angle end of the lens' range, or f/5.6 and f/9.6 at the telephoto end. Sony claims a High-Speed Scan TTL autofocus system for the P1, but we confess we don't know what this means, given that shutter lag was actually a bit slower than average in autofocus mode. We did find that the autofocus system worked well down to light levels of 1 foot-candle (11 lux), and reasonably well to 1/2 foot-candle (5.5 lux). The lens' working range runs from 19.75 inches (50 cm) to infinity in normal mode. In macro mode, the focal distance ranges from 4.0 to 19.75 inches (10 to 50 cm). A Panfocus capture mode (one of the Program AE selections) allows for swift focus changes between infinity and shorter focal distances. Another Program AE mode, Landscape, fixes the focus at infinity, for capturing far away subjects.
The DSC-P1 features what Sony calls a 6x Precision Digital Zoom, which they claim allows you to get better quality images from digital enlargement than would normally be the case. Digital zoom basically crops-out and enlarges the center of the CCD image, thereby decreasing resolution and increasing image noise and pixelation. Sony's Precision Digital Zoom utilizes an advanced interpolation technology to improve the image quality when using digital zoom, which they claim results in a better looking final image. We believe this to be the same interpolation technology first introduced on the DSC-F505V digicam, which we had the privilege of introducing to the world in early June of 2000. At that time, we studied the Precision Digital Zoom technology in some detail, and found that it did indeed perform better than post-exposure interpolation in Photoshop(tm), although the difference was slight. Overall, digital zoom is still digital zoom, trading resolution for apparent magnification. Sony's technique appears to offer some advantages over conventional approaches, but the end result can't remotely be compared to the effect of a true optical zoom lens. The P1's digital zoom feature is only available on still images.
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