A good bet for the tele-macro fan
This is Pentax’s longest digital macro lens offering 1:1 magnification from a minimum distance of 30.3cm. It features much the same specification as the shorter 50mm, and it’s compatible with both digital and film SLRs using the Pentax KAF lens mount.
The SMC coating reduces surface reflections and flare, and a lens hood is also included. The nine elements are arranged in groups of eight, and the lens has the one-touch auto-to-manual focus again seen on the 50mm version. It also has the same focus lock: once the subject is in focus you can lock the position of the lens. There’s also an aperture ring, which must be set to A in order to function with digital cameras.
The performance is impressive, with good results throughout the aperture range and peak performance at f/5.6, before levelling to f/11 and tailing off as you approach the minimum aperture. The optic also produces great sharpness throughout, while fringing at the centre of the images stays invisible throughout the range, with just minor fringing occurring at the centre from the mid apertures onwards.
One of best 100mm lenses available