I picked up this lens at a camera show maybe 25 years ago.
Carl Zeiss Jena (West Germany) Triotar telephoto, f/4, 13.5cm (135mm), coated 3 element optics.
It dates to the 1950s and was produced in more than one dedicated mount. This one is m42 universal screwmount, to fit many popular SLR bodies of that age.
This lens is rather heavy solid metal construction, and weighs in at about 18 ounces, but remains relatively compact.
Focus is to a nice near 5 feet, which makes it practically a macro on a digital body with a 2/3 frame sensor.
The damage to the front plate is from my efforts to disassemble the optics, since they really needed internal cleaning. The brass ring was practically welded in there due to age, and I drilled the holes to allow a heavy duty tool to do its work. It hurt the cosmetics, but made the lens very functional.

It had been a while since I had used this lens, and this was the first time I have used it to shoot digital. The Pentax digital bodies make it easy to adapt to a wide assortment of older lenses.

Locations are Meramec River, Minnie Haha Park, and our front yard.
As usual for me, everything is hand held. The mass and shape of the lens helped to steady my shots.
I liked the the results.

Please click on thumbnails to see enlarged.
All images are Copyright 2016 E.J.Kowalski.
Thanks! Ed