what is compatible with Ricoh p-mount (screw mount)?

Discussion in 'Ricoh' started by Theo, Dec 3, 2004.

  1. Theo

    Theo Guest

    Hello all,

    I have an old Ricoh with "standard p mount" screw thread lenses, according
    to the manual.

    What other brands or mount systems are compatible? Are all screw mounts,
    such as Pentax and Leica, compatible? Was p-mount a Ricoh thing, or an
    industry standard? All I've heard is that p-mount lenses have a pin that
    can drop into a hole on other screw mount camera bodies, making removal
    impossible (or at least expensive).

    Theo, Dec 3, 2004
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  2. Which Ricoh? A Singlex TLS, perhaps?
    I suspect that you just have an M42 thread mount. Normally thought of
    as the Pentax screw mount, but the pedantic will point out that it was
    used on an East German Zeiss product first.
    Stephen H. Westin, Dec 3, 2004
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  3. Theo

    LEDMRVM Guest

    I have an old Ricoh with "standard p mount" screw thread lenses, according
    Correct. The Singlex Series used the 42mm Praktica/Pentax thread mount.

    LEDMRVM, Dec 3, 2004
  4. Theo

    Jeremy Guest

    Ricoh used the screwmount--so called because the lens screwed into the
    camera. This was commonly known as the "Universal" mount, the "M42" mount
    and the "Pentax Screw Mount," because Pentax was the predominant line of
    cameras that used it.

    There are tons of used lenses available that fit that mount. Check eBay
    under keywords Screwmount and "M42," and you'll see them.

    Among the other lenses that used that mount were Mamiya-Sekor, Fuji, Chinon,
    Vivitar, Carl Zeiss Jena, Sears, Penney's (both were Ricoh under private
    label), and Pentax.

    Your lens probably has a single pin on the back. That would be for the
    automatic diaphragm link with the camera.

    In 1975, Pentax switched from screwmount to K-mount (bayonet). All the
    other screwmount lens manufacturers followed suit. You can use a screwmount
    lens on a K-mount camera WITH AN ADAPTER. You CANNOT use a K-mount lens on
    a screwmount body, because the rear element is larger on the K-mount than on
    the screwmount. Pentax designed the newer K-mount to allow photographers to
    continue using their screwmount lenses on the newer bayonet bodies. The
    presumption was that the lenses would outlast the camera bodies--thus the
    new camera mount was backward compatible with the old-style lens mounts.

    There is, to the best of my knowledge, only ONE model camera in current
    production. That is the Voightlander Bessa TM. You can see it on

    If you want a used body, the Pentax Spotmatic and Spotmatic II would accept
    your lens without an adapter. If you want to keep your Ricoh camera, but
    use better lenses, I recommend the Asahi Pentax SMC Takumar line. Have a
    look at the following link:

    Jeremy, Dec 3, 2004
  5. Theo

    Jeremy Guest

    No, the LEICA SCREW MOUNT was not the same size as the other screwmount lens
    mounts. Leica was, I believe, 39mm while the Universal "Pentax" Screwount
    was 42mm (thus the designation "M42").

    Just dismiss Leica from your list to be considered and everything else will
    work fine.
    Jeremy, Dec 3, 2004
  6. Theo

    Theo Guest

    Thanks to everyone!
    Theo, Dec 3, 2004
  7. Theo

    Bandicoot Guest

    Later SMC Takumars have a small pin in the mount that is on the surface that
    bears against the 'front' of the body mounting ring when they are screwed
    on. (This pin is to stop the lens accidentally getting switched from auto
    to manual diaphragm while it is off the body.) These may be the ones you
    are thinking of that can get 'locked' to certain bodies where the 'front' of
    the body mount is not smooth. If this does happen, very careful use of a
    feeler gauge can usually undo it - same principle as opening a door with a
    credit card.

    Bandicoot, Dec 4, 2004
  8. Theo

    Jeremy Guest

    The "Auto/Manual" switch on the Super-Takumars and the SMC Takumars was yet
    another example of Asahi's commitment to backward compatibility.

    When the Super Takumar lens line was introduced, to replace the Takumar
    lenses, the new lenses featured something revolutionary at the
    time--"automatic diaphragm." It enabled the photographer to focus and
    compose his shot at full aperture, rather than at shooting aperture.
    Considering that one of the major drawbacks of SLRs in general was their dim
    viewfinders, this was a major improvement. The photographer could set his
    aperture, but when he looked through his viewfinder the lens was wide
    open--allowing as much light as possible into the viewfinder to make
    focusing easier. When the shutter was fired, the lens stopped down to
    shooting aperture for just a moment.

    But, when the Super Takumars were introduced, many Pentax photographers
    still had older bodies, that did not have the linkage to close down the lens
    at the moment of exposure. So Asahi added an "auto/manual" switch onto the
    lens. If the lens was mounted on one of the older cameras, the switch was
    placed in the manual position, and the lens operated much like a preset.
    The aperture had to be stopped down to shooting aperture before the shot was

    Asahi users could now continue adding to their lens collection and use those
    new lenses with their older camera bodies, in manual mode. If they
    subsequently purchased newer bodies, with the preview switch, they could
    simply switch their Super-Takumar or SMC Takumar lenses to the "auto"
    position, and they would be able to exploit the automatic diaphragm feature.
    Pretty neat, eh?

    Now there was one loose end left: that switch was unnecessary when the lens
    was mounted on a newer body. In fact, if the switch was left in the
    "manual" position, the automatic diaphragm was disabled, and a major feature
    of the new camera body was rendered useless. The switch could go into the
    incorrect position in two ways: First, the photographer might mount the
    lens with the switch in the manual position. But the other way--and the
    more likely way--would be if the lens was mounted and was in use, and the
    photographer inadvertently nudged it from auto to manual.

    So the challenge facing Asahi engineers was how to disable that switch when
    it was not needed--i.e., when the lens was mounted on one of the newer
    bodies with the preview switch.

    Their answer was that tiny little pin, so small it goes virtually unnoticed.
    Asahi cut out a tiny section of the new screw mounts so that the pin would
    be allowed to stick out when the lens was mounted on any of their new
    bodies. And when that pin was out, the auto/manual switch was locked--it
    could be moved from manual to auto, but once in the auto position, it could
    not be moved back to the manual position--at least as long as the lens
    remained mounted on one of the new bodies.

    What this meant was that, once a lens was switched into the auto position,
    the switch remained there--it would not be allowed to return to manual by

    Many people do not understand this function, and I routinely see these
    lenses offered on eBay with a disclaimer that the auto/manual switch is
    "stuck." It is not defective, and in fact is performing as it should.
    Sometimes people force the switch, and they break the mechanism.

    All one has to do is screw a Takumar rear lens cap onto the lens, and it
    will push the little pin in, and the auto/manual switch then can be freely
    moved from one position to the other.

    If anyone is going to buy a Pentax screwmount lens, the Super-Takumar or SMC
    Takumars have the backward compatibility built in, and they are to be
    preferred over the older Takumar or Auto-Takumar lenses.

    Unfortunately, there was one problem with this setup. The original Asahi
    Bellows II (there were two different Bellows II models) had a screw located
    where it often would get caught in that tiny little cutout on the camera's
    lens mount. If that happened, it required a technician to free it, or it
    would break if forced. The bellows had already been discontinued by the
    time the newer bodies had been introduced, but they are still sold on eBay
    today to unsuspecting people that do not know about the incompatibility.

    Despite this one unfortunate glitch, Asahi really has made a commitment to
    maintain compatibility between its newer and older equipment. When they
    went to the K-mount, they did not abandon their screwmount customers, as
    Canon did when they orphaned the breech mount. Lots of people continue to
    use those superb Takumar screwmount lenses on newer K-mount camera bodies.
    Then there are those luddites like me, who stayed with screwmount bodies all
    along, and never bothered to upgrade to the K-mount. For those of us that
    shoot primarily static subjects, why bother . . . ?
    Jeremy, Dec 4, 2004
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