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M42 mount problem - advice needed

Discussion in 'Adapted Lenses' started by Ramsey, Mar 1, 2013.

  1. Ramsey

    Ramsey Mu-43 Top Veteran

    Jan 9, 2013
    Zagreb, Croatia
    So i just received my M42-M43 adapter (generic ebay adapter) and i wanted to test my newly acquired Helios 44M-5 58mm f2 and Soligor 135mm f3,5.

    These are my first M42 mount lenses, and i like the mount, no hassle, simply screw in the lens until the end and that's it.

    Helios - apart from the fact that the lens has focus ring in front of aperture ring (takes a bit getting used to), it seems fine. Also, aperture has 11 points, (for f2-f16) so i guesss those are half stops.
    However, the lens has a pin in the mount that activates the aperture blades, and when i place the adapter, the pin is not pushed in (resulting in a constant wide open lens). Do i need another adapter or do i need to perform some sort of witchcraft (tape or sth similar) in order to have the pin pushed in at all times?

    Soligor works fine with the adapter (smooth aperture changing, no clicks).

    Can anyone help?

    Left is Helios, right is Soligor.

    View attachment 260908
  2. DeeJayK

    DeeJayK Mu-43 Hall of Famer

    Feb 8, 2011
    Pacific Northwest, USA
    I suspect what you need is an M42-:43: adapter with an "aperture pin shoulder" (such as this one from Fotodiox) which should depress the pin on lenses like your Soligor.
    • Like Like x 1
  3. Ramsey

    Ramsey Mu-43 Top Veteran

    Jan 9, 2013
    Zagreb, Croatia
    That makes sense, thank you very much.

    I knew there were different makers (and qualities) of adapters, but i didn't suspect they have different functionalities.
  4. snaimpally

    snaimpally Mu-43 Top Veteran

    Dec 31, 2012
    I have seen some discussion regarding removing a pin for PK lenses. Probably doesn't apply to M42, but here it is:

    Hidden gems among lenses - Personal View Talks

    Most of my M42 lenses have a "automatic/manual" switch that needs to be placed in the manual position to have the aperture close down.
  5. dwig

    dwig Mu-43 Top Veteran

    Jun 26, 2010
    Key West FL
    I wouldn't say "most" do.

    Originally, when full auto-diaphram action appeared on M42 thread mount (aka: Praktica/Pentax thread) lenses the lenses themselves had some stopdown mechanism to provide for depth-of-field preview and to allow for use on older bodies and accessies (e.g. extension tubes, bellows, reversing rings, ...) that didn't provide for the auto-diaphram mechanism. All Asahi (now Pentax) Takumar lenses that had auto-diaphram action had an A/M switch for this purpose. Most other early lenses that cloned the Asahi/Pentax pin system also had a similar feature.

    When TTL meters became common, many manufactures, though not Asahi/Pentax, began to omit the lens' stopdown switch/button. The bodies' meter switchs provided for the DOF use and most of their non-auto-diaphram accessories acquired a ramped flange to press the pin, keeping the lens the stopped down.

    There are a lot of non-Asahi/Pentax M42 lenses out there that lack any stopdown lock of their own. To adapt those to m43 you need either an adapter that presses and holds the pin in or you need to modify the lens to keep the pin pressed (e.g. bending the pin and jamming it in, which I don't recommend). While such adapters with an "aperture pin shoulder" are the best choice with lenses lacking the A/M switch, they are less desirable for use with lenses that do have their own switch. When the lens has its own switch and the adapter doesn't press the pin the combination acts as a preset lens rather than a full manual lens. Preset lenses allow you to "preset" the desired aperture and then operate some second control (e.g. the A/M switch or Open/Close or O/C ring) to quickly switch between wide open (for viewing and focusing) and working aperture (your preset f/stop) without having to remove your eye from the VF and look at the lens.
  6. WJW59

    WJW59 Mu-43 Veteran

    Feb 20, 2011
    Completely different topic. The Ricoh Pentax lens mount variant has a pin that will drop in the the Pentax AF screw drive connector and make the lens difficult to impossible to remove (be there, done that). This is the pin the article is referring to.
  7. Ramsey

    Ramsey Mu-43 Top Veteran

    Jan 9, 2013
    Zagreb, Croatia
    Thx everyone for the replies.

    I'll do some teeting today (limited to wide open lens) but i don't think i'll keep the lens though, the need for additional adapter and the fact that this lens does not offer any significant advantage over OM 50mm 1,8, i don't think i'll use it that much.
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