HD PENTAX-D FA 24-70mm F2.8 ED SDM WR

HD PENTAX-D FA 24-70mmF2.8ED SDM WR. A Large-aperture standard zoom lens for 35mm-format full-frame digital SLR camera

This high-performance, interchangeable standard zoom lens for use with PENTAX K-mount digital SLR cameras, providing exceptional imaging power and a large F2.8 maximum aperture. This zoom lens with an universal focal length range of 24-70 mm is a perfect standard zoom lens and the perfect addition to the HD PENTAX-D FA 70-210mm F4 ED SDM WR and HD PENTAX-D FA* 70-200mm F2.8ED DC AW telephoto zoom lenses.

The maximum aperture of 2.8 over the entire zoom range to deliver brilliant image quality and many other first-class features meet the highest standards – and are already aligned with the high technical requirements of future PENTAX cameras.

When mounted on a 35mm-format full-frame digital SLR camera body, this zoom lens offers a zoom ratio of approximately 2.9 times to cover the ultra-wide-angle to standard ranges (24mm to 70mm in focal length). It not only covers the focal-length range most frequently used for ordinary subjects, but also provides ultra-wide-angle coverage to produce distinctive visual expressions, such as exaggerated perspectives or extra-wide depths of field, making it very useful with subjects such as sweeping landscapes and shallow in-door scenes.
When mounted on a current K-series digital SLR camera body with APS-C size sensor, it provides focal lengths from 37mm to 107mm in the 35mm format to cover wide-angle to medium-telephoto ranges.

Since its large maximum aperture not only creates an excellent bokeh (defocus) effect on the background for beautiful portraits, but also allows the photographer to handhold the camera for poorly illuminated subjects, such as sunsets and indoor scenes.

*Geometric optics MTF
(MTF calculated without referencing the effects of light diffraction phenomenon)
**Wave optical MTF (MTF calculated referencing the effects of light diffraction phenomenon)

MTF chart information

MTF (Modulation Transfer Function) is a kind of index used to evaluate lens performance, which represents the extent of subject contrast reproduction as spatial frequency.
The MTF chart here shows the contrast on the vertical axis, and distance from the center of the image on the horizontal axis. For the spatial frequency, 10 lines/mm shows a low frequency, and 30 lines/mm shows a high frequency, resulting in the MTF graph. On the graph, the solid line represents the S direction (sagittal direction and radiation direction) MTF, and the broken line represents the M direction (meridional direction and concentric circular direction) MTF.
In general, a low-frequency MTF is proof of a clear, high-contrast lens, and a high-frequency MTF is proof of a sharp lens with high resolving power.