Pentax Screw Mount (PSM) Lenses

by Karen Nakamura

Other Classic Camera Lens Mounts
Contax / Nikon RF Bayonet Mount
Canon FD/FL Breechlock Mount
Leica Screw Mount (M39)

Overview and Personal Comments

The first camera to usethe M42 x 1mm screw mount was the Contax S released in 1949. Zeiss also sold Contax cameras under the Pentacon name and when they were absorbed by the KW company, they changed names to Praktica. Many in Japan know the M42 mount as the "Praktica" screw mount.

However, in the United States this mount system has become synonymous with the Pentax Spotmatic camera of 1964, which popularized it stateside. In addition to Pentax, a wide variety of manufacturers used the M42 mount: Ricoh, Chinon, Contax, Pentacon, Exa, Voigtländer Icarex, Mamiya, Olympus, Yashica, Zenit and more. It's a very flexible lens mount, able to accomodate a variety of camera designs. Unfortunately bayonet-type mounts became more popular in the 1970s. This eventually led to its demise in the 1970s with the advent of proprietary bayonet mounts (Pentax K, Nikon AI, Canon FD, etc.).

The M42 market has received a recent shot in the arm with the recent Cosina announcement of their release of a new M42 mount camera, the Voigtlander Bessaflex TM (the TM stands for Thread Mount, not TradeMark). The estimated street price should be between $300-400. They've also released a series of M42 mount lenses to go with the camera. I'm very excited about the new lenses, but less with the camera. Why buy a Bessaflex when you can get a Spotmatic for between $150-200? I guess some people want the warrantee of a new camera. But the lenses are very exciting.

I use my M42 lenses with my Asahi Pentax Spotmatic II. The thing I find most annoying about Pentax lenses is that they are mostly left-focusing (infinity at left) while most of the world is right focusing (infinity at right).* If the optics on the SMC Takumars weren't so stellar, I'd be sore pressed to use them.

* Just to be contrary, Nikon is also left-focusing. Canon, Zeiss, and Leica are right focusing.

News from Japan: While in Japan over the summer for some research, I just picked up a Canon EOS-to-M42 mount adaptor. This will allow me to use my Canon EOS-3 with my M42 lenses. I occasionally use the Pentax lenses with my Canon 10D digital SLR with an adapter.

Auto Takumars vs. Super Takumars vs. Super-Multi-Coated Takumars vs. SMC Takumars

Pentax produced at least four different series of lenses, starting with the original Auto-Takuamrs, the Super-Takumars, the Super-Multi-Coated Takumars and the SMC Takumars. Several people have asked me about the difference between the different models. I didn't know and hate not knowing, so I did a bit of research and found out the following things:

• The seven layer SMC Coating was developed in 1971. The coefficient of refraction r = 0.998!
• The Super Takumars before then do not have the SMC coating but are still coated. Some late production Super Takumars are multi-coated.
• The Super-Multi-Coated Takumars and the SMC Takumars are essentially the same optic design, although the barrel design was changed to a rubberized focusing ring.
• SMC Takumars (post 1971) have a full aperture metering lug/protusion that allows them to be used on Spotmatic ES and F models. But this lug gets in the way of other M42 cameras, so use them with caution on your Prakticas, for example.

For more information, see this page.

I have sample photographs using the Pentax 17mm f/f4 Fish-eye Takumar on my PAW2004-18 page.

Technical Details-Wide Angle Lenses

Technical Details-Standard Lenses

Technical Details-Telephoto Lenses

Bellows Extension and Slide Duplication

One of the beauty of the PSM system is the wide variety of accessories that are available for it. In a used camera store I found this Prinz extension bellows for Pentax screw mount. These types of bellows units are expensive in other mounts (especially Canon EF mount), but the PSM version was reasonable.

I then found the Accura Slide Duplicator new in box. It came with a bunch of adaptors, one of which fit perfectly on a Pentax 50mm lens. Combined with the Prinz bellows extension, it allows for full duplication of slides and negative films. Combined, the cost for both was much less than $100.

Pistol-grip Sun Hi-Tele Zoom Lens f/85 - 210mm F=4.8

I found this oddball lens a couple of years ago. It's a 85-210mm zoom for the Pentax M42 mount that has a pistol grip. My guess is that it was designed for sports photographers. It is most probably a fairly old lens, from the 1970s or early 1980s.

The pistol "trigger" closes down the lens. There's a small screw-in port on the rear that I assume allows one to screw in a cable that will couple it with the lens shutter. Unfortunately, it didn't come with the coupler.

There is also no stop-down pin on the lens which would allow it to couple with the lightmeter on the Spotmatic series cameras. Since the rear lens M42 mount is on a screw-in adapter, my guess is that at the time it was sold with different adapters in mind, so could be modified to be used on any camera (since shutter synchronization was done through the screw-in cable).

I'm selling this lens on ebay in order to refine my collection a bit: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330100075341

Tele-Astranar Lens 500 mm f/8

The other third party lens that I found was a Tele-Astranar 500mm f/8 for the Pentax M42 mount. This was made before the introduction of retrofocus optics which allowed for shorter lens designs. So it's an honest 500mm long. The aperture isn't so great, f/8 ~ f/22, with fully manual stop-down. The closest focusing is 12 meters or 40 feet, so it was clearly designed for sports or for astronomic photography. My guess is the latter given the name, Tele-Astranar. It still has the JCII stamp indicated that it was made in 1966.

I bought it in like-new condition with the case, tripod mount, and an "Astranar Skylight 72mm" lens filter on it.

I'm selling this on ebay at: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330100076337

Lens Collection Martrix

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