A full-frame 24mm to 240mm zoom range allows this one lens to cover an extensive variety of shooting situations with 10x effective zoom range, making it ideal for landscape, snapshots, portraits and travel where reducing luggage is a priority. The ability to switch from wide angle to telephoto without having to change lenses also means that more of those fleeting moments that make great shots will be captured. The advanced optics include 5 aspherical elements and 1 ED glass element, achieving high-quality performance in a compact overall design. An advanced linear motor drives the focusing mechanism for quick, smooth response throughout the extended zoom range. Handheld telephoto shots and low-light photography are facilitated by built-in Optical SteadyShot (OSS) image stabilization. Like all other FE lenses, the design is dust and moisture resistant.
Circular Aperture
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.
Aspherical lens elements
Aspherical lens design dramatically reduces spherical aberration while also reducing lens size and weight. Spherical aberration is a slight misalignment of the light rays projected on the image plane. This is caused by differences in refraction at different points on conventional spherical lenses which degrade image quality in large-aperture lenses. Specially shaped "aspherical" elements near the diaphragm restore alignment of light rays at the image plane, maintaining high sharpness and contrast even at maximum aperture and can also be used at other points in the optical path to reduce distortion. Well-designed aspherical elements can reduce the total number of elements required in the lens, thus reducing overall size and weight.
Internal focusing
Only the middle groups of the optical system move to achieve focus, so the overall length of the lens does not change. Other important benefits include fast autofocusing and a short minimum focusing distance. Also, the filter thread at the front of the lens does not rotate, which is convenient if you're using a polarizing filter.
Lens-based optical image stabilization
Gyro sensors built into the lens detect even the slightest movement, and the stabilization lens is precisely shifted to counteract any image blur that might occur. The use of precision, quiet linear motors and technology inherited from high-end Sony professional camcorders results in exceptionally quiet, effective image stabilization that contributes to high-quality movies as well as stills.
