Pentax's medium-format wide — the SMC Pentax 6x7 55mm f/4, rectilinear on the 6x7 frame.
The SMC Pentax 6x7 55mm f/4 is a wide-angle lens for the Pentax 6x7 medium-format system, from the SMC Pentax 6x7 generation of the line. It replaced the earlier Super-Takumar 6x7 55mm f/3.5 as the wide-angle option at this focal length, carrying the SMC coating and updated optical design for the large 6x7 negative.
This is a manual-focus lens for the Pentax 67 bayonet mount, covering the 6x7 cm frame. It has a fixed 55mm focal length and a maximum aperture of f/4. On the medium-format frame this gives a moderate wide-angle view, and the Super Multi Coating denoted by the SMC name controls flare and ghosting when shooting toward bright light.
The lens is a corrected rectilinear wide that keeps lines straight, suiting landscapes, interiors and architecture on the big negative. Depth of field is generous, and moving to the middle apertures pulls up edge sharpness across the wide field, which matters given how much detail the 6x7 frame can hold.
On the used market this wide is a practical choice for 6x7 shooters and appears more often than the fisheyes. Check the elements for haze and scratches, look for fungus given its age, and confirm the aperture ring clicks positively with dry blades. It works on mirrorless bodies through a Pentax 67 mount adapter for those adapting the glass to digital.