This is the original Adaptall 300mm f5.6. It was superseded by the CT-300
, which is reviewed separately.
Focus turns the opposite way to Pentax, and minimum focus to infinity is 270 degrees; 3/4 of a turn. The front element rotates as you focus. The lens has a built-in lens hood and tripod mount/collar.
The optical design is suspected to be the same as for the Adaptamatic 300mm f5.6
The lens has an M/A switch, so can easily be used in Aperture Priority mode on a Pentax DSLR without a PK/A adapter.
Weight: 869 g including Adaptall mount
Length: 22 cm including mount
Filter size: 62mm
Maximum Diameter (including tripod mount): 8 cm
Aperture blades: 9 straight
Minimum focus distance: 2.4 m
Maximum aperture: 5.6
Minimum aperture: 32
Accepts SP 2X tele-converter #01F and SP 1.4X tele-converter #140F. Note: TC's are reviewed in miscellaneous lenses - TC's