The Canon 100mm has Canon’s typically reliable and tough build quality, and – because it’s also suitable for full-frame cameras – is fairly heavy, too.

The optical train is made up of ten elements in nine groups, while the minimum aperture of f/32 allows plenty of depth of field. The lens has a dual switch for focus limiting and a separate switch for switching between autofocus and manual focus. It also offers full-time manual focus while in autofocus mode for fine tuning.

Like some other optics that are in the longer focal range, the Canon 100mm MTF charts are less impressive than that of the shorter focal lengths.  Best performance for sharpness is achieved at f/8, and this holds steady until f/16 when sharpness begins to dip

Where the lens really performs well is in its control of chromatic aberrations which is very impressive.