M42 Screwmount Lens

M42 Open-aperture Metering Version

Aperture range: f/1.8 to f/16; half stop increments from f/1.8 to f/8, full stop from f/8 to f/16

Six elements in five groups

Manual Focus

Filter Size: 49mm

Selling 1x lens - comes with 1x rear lens cap only.

Condition: Good

No image-threatening particles in the lens; no more than what is normal for this 1970s era of photography gear.

No problem with aperture blades.

Smooth focusing.

No name plate; distance scale is no longer fixed in place, so zone focusing may be out of the question.

I've used it and found no flaws in the resulting pictures. Kept in a dry box when unused.

More specs: Super Multi Coated (SMC) coating, 201g, rubberized focus ring. Has aperture ring, 6 aperture diaphragm; minimum focus 45cm; no weather sealing. Made by Asahi Optical Co., Ltd. in Japan from 1972 to 1975. Now known as 'Pentax Corporation'. Product code: 37106.

A brief look at the lens (adapted from Josept Albert, 2002): The M42 screw mount comes in two versions: one with open-aperture metering (which came later), and one without (the 'original'). All M42 lenses can mount to a Pentax Spotmatic series camera. The SMC Takumar is one such lens that supports open aperture metering (specifically, the Spotmatic F, ES, and ESII). It can get stuck on non-Pentax screw mount camera bodies (e.g. Mamiya, Praktica, other Russian cameras). Source- http://photo.net/bboard/q-and-a-fetch-msg?msg_id=001smp

Reason for reduced price: no nameplate & distance focusing scale is not perfect.

FAQ Why is the glass yellow / yellowish? This is likely due to thorium oxide being used in the manufacturing process of some of the glass elements in the lens, a standard practice in its day. This is a naturally occurring process. Some Internet users say that exposing this lens to sunlight (UV radiation) helped to reduce or eliminate the yellowing; however, there is no substantial evidence that this applies to all yellowed lenses.  

Recommendations If you want to shoot film on the Pentax system, use this lens. If you want a cheap, fast prime for adapting to other camera systems, use this lens. 

See also: http://www.pentaxforums.com/lensreviews/SMC-S-M-C-Super-Auto-Takumar-55mm-F1.8.html