DT 55-300mm F4.5-5.6 SAM Zoom Lens
Super-value Sony α (Alpha) SAL-55300 telephoto zoom. This compact, lightweight 55-300mm f4.5-5.6 Telephoto Zoom Lens covers the medium to long-distance telephoto range families use most often, with close 4-1/2 foot (1.4m) minimum focusing distance for all-around utility - plus ED (Extra-low Dispersion) glass to virtually eliminate color distortion (35mm equivalent: 82.5-450mm).
When changing your aperture to defocus the background, the light sources appear blurred. This ‘bokeh’ effect of the blurred background can be enhanced with circular aperture blades used in this lens. Conventional aperture blades have flat sides creating unappealing polygonal shaped defocussed points of light. α lenses overcome this problem through a unique design that keeps the aperture almost perfectly circular from its wide-open setting to when it is closed by 2 stops. Smoother, more natural defocusing can be obtained as a result.
ED (Extra-low Dispersion) glass
As focal lengths get longer, lenses built with conventional optical glass have difficulties with chromatic aberration, and as a result images suffer from lower contrast, lower color quality, and lower resolution. ED glass dramatically reduces chromatic aberration at telephoto ranges, and provides superior contrast across the entire image, even at large aperture settings. Super ED glass provides enhanced compensation for chromatic aberration.
The distance encoder plays an integral part in ADI flash metering, which delivers high precision flash metering that is unaffected by the reflectance of subjects or backgrounds. The distance encoder is a lens component that directly detects the position of the focusing mechanism, and sends a signal to the CPU in order to measure distance to the subject. During flash photography, this data is very useful in calculating how much flash output is appropriate to the scene.
SAM (Smooth Autofocus Motor)
Rather than using the focus drive motor in the camera body, SAM lenses feature an autofocus motor built into to the lens itself that directly drives the focusing element group. Since the built-in motor directly rotates the focus mechanism, operation is significantly smoother and quieter than conventional coupled autofocus drive systems.
2012 Sony Electronics, Inc.
All rights reserved. Sony, the Sony logo, Alpha, “α” and Super SteadyShot are trademarks of Sony. All other trademarks are trademarks of their respective owners.