The Pentax 67 mount is technically obsolete, but calling it irrelevant would be a mistake. The system was created in 1969 for the large Pentax 6×7 film camera, later renamed Pentax 67, and it remained in production until the early 2000s. Pentax eventually ended development when digital photography overtook medium-format film systems, and no modern digital camera bodies use the Pentax 67 mount natively. In that strict sense the mount belongs to a discontinued ecosystem.

Mirrorless cameras changed the old logic of lens systems. The short flange distance of the Canon RF mount suddenly opened the door for optics that were never meant to sit on small digital bodies. Medium-format lenses — once built for giant film frames and heavy studio cameras — can now be mounted on relatively compact mirrorless cameras with a simple mechanical adapter. The result is a curious mix of eras: huge image circles feeding modern sensors, often producing images with a slightly different rendering character than contemporary digital lenses.