Pentax's ED super-tele — the SMC Pentax 6x7 800mm f/6.7 ED, extreme reach on the 6x7 frame.
The SMC Pentax 6x7 800mm f/6.7 ED is a super-telephoto lens for the Pentax 6x7 medium-format system, from the SMC Pentax 6x7 generation of the line. It uses extra-low-dispersion glass, marked by the ED suffix, to control chromatic aberration at extreme focal length on the large 6x7 negative, one of the longest lenses in the system.
This is a manual-focus lens for the Pentax 67 bayonet mount, covering the 6x7 cm frame. It has a fixed 800mm focal length and a maximum aperture of f/6.7. The ED glass curbs colour fringing that would otherwise be visible at this reach, and the Super Multi Coating denoted by the SMC prefix holds contrast across the very long telephoto field.
The 800mm reach delivers extreme perspective compression and pulls in far-distant subjects on the 6x7 frame, suiting dedicated wildlife and distant landscape work. It is a very large and heavy lens demanding a robust tripod and careful technique, and the ED correction preserves the fine detail the big negative can hold at range.
On the used market this ED super-telephoto is a rare and costly specialist item bought by a small number of committed 6x7 shooters. Inspect the large front element carefully for marks and haze, check the long barrel for internal fungus, and confirm smooth, dry focus and aperture actions. It adapts to mirrorless through a Pentax 67 mount adapter.