I have the Vivitar Series 1 135mm f/2.3 manual focus lens for Pentax screw mount cameras such as the Spotmatic. Also fits all other cameras using the 42mm diameter Pentax screw mount, such as Chinon, Fuji, Yashica, Ricoh, etc. Has a manual/automatic diaphragm switch so it can be used in stop down mode in conjunction with inexpensive mount adaptors. With a, say, Pentax screw mount to Pentax K mount adaptor, this lens can be used on any Pentax bayonet mount camera, from the K-1000, LX, ME, MX, ME Super to the latest Pentax autofocus models. Similar adaptors are available for most other brands of cameras. This lens was built in the same era in which such other well known and highly regarded Series 1 lenses as the 90mm f/2.5 macro, the 200mm f/3 telephoto, the 70-210mm f/3.5 macro, the 90-180mm f/4.5 flat field macro zoom, the 600mm f/8 and 800mm f/11 "solid cat" lenses, and the 28mm f/1.9 wide angle lens were built. What a lineup! The design philosophy for this batch of lenses is maximum performance. And they deliver! This 135mm lens takes 72mm filters, and measures just under 4" long at infinity. It has a built-in retractable sliding lens hood. Minimum focus is 3 ft., compared to 5 ft. for most 135mm lenses. Maximum magnification ratio is an impressive 1:4.5. Optical construction is 6 elements in 6 groups, compared to the 4 element in 4 group design of most 135mm lenses. The VMC multi-coating makes sure that flare is kept to the absolute minimum.

Here is an example of an existing light photo with the Vivitar Series 1 135mm f2.3:



Wayne