This wide-angle lens features super multi coating (SMC) and an equivalent focal length of 36mm, in the 35mm format. SMC is standard for all PENTAX lenses and describes seven microscopically thin layers of high quality coatings that are applied to the lens elements to reduce reflectance and increase transmittance. It significantly increases the amount of light transmitted by the lens.
The smc PENTAX-FA645 45mm F2.8 lens features exceptionally clear, high-contrast delineation performance with minimum edge to edge distortion. The large flower-shaped hood enables a higher sense of transparency even under backlit or other adverse conditions. Combined with the brightness of an F2.8 aperture, this lens provides an outstanding natural out-of-focus (bokeh) effect with a wide angle field of view. The AF/MF operation can be performed quickly by simply sliding the entire focus ring forward or backward, while the manual focus operation can easily be altered after AF to allow for fine focus adjustments.