A medium-focus, manual, autofocusing telephoto lens provides a 35mm-equivalent focal length of 157mm and gives images a soft bokeh (or out of focus) background effect. Two Extra-low dispersion elements enhance quality by correcting chromatic aberration, while ghost-less coating prevents refraction on the lens’ inner surface. The result is a sharper image with higher contrast. Added is an Inner Focusing (IF) mechanism to improve speed and reduce lens extension. Photographers, in response, can get a closer minimum focus distance. Compatible with both film and digital PENTAX 645 cameras.