Adapter Question

Discussion in 'Adapted Lenses' started by rayvonn, Oct 4, 2017.

  1. rayvonn

    rayvonn TalkEmount Regular

    61
    Jan 3, 2016
    Apologies if this sounds a bit naive or silly, but it's something I'd like to know and here's a good a place to ask as any.

    Is there an adapter which is 'thin', or makes you feel that you are connecting your adapted glass to your A7 natively? Or to put it another way, I have a Takumar 50mm F1.4. Lovely lens of course and lovely size - but the size isn't lovely when I add it onto my camera with my K&F adapter. The adapter's great but the lens looks huge, almost ungainly when attached to it, especially when imagining it on an original film camera.

    I do appreciate that this is truly a first world problem in these troubled times and that maybe the answer's 'no' - but I thought I'd ask.
     
  2. firemist

    firemist TalkEmount Regular

    180
    Dec 4, 2015
    Rayvonn,

    Your Takumar lens was designed to focus at infinity on a film Pentax SLR camera. The flange focus distance for Pentax SLRs is 45.46mm, meaning the distance from the lens mount ring to the film (or sensor these days) has to be just that distance, 45.46mm for your Takumar to focus to infinity. However, the flange focus distance for Sony E mount is 18mm. Therefore, in order for your Takumar lens to focus at infinity on your A7, the adapter has to be 45.46-18=27.46mm thick (just over 1"). There is no escaping this.
     
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  3. AlwaysOnAuto

    AlwaysOnAuto TalkEmount All-Pro

    Feb 17, 2015
    Rayvonn - I have the same complaint about the Nikon adapter I use, but there's no getting away from it.
     
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  4. bdbits

    bdbits TalkEmount All-Pro

    Sep 10, 2015
    Bob
    Yep, it's all about the flange distance. So if you want thin adapters, you need a mount that is as close to 18mm as you can without quite getting there, as the adapter is going to add some thickness. There is a nice chart at Flange focal distance - Wikipedia that lists flange distances. Leica M is a popular choice if you want relatively thin adapters and smallish lenses, but can have some issues particularly in the corners for very wide-angle lenses.
     
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  5. WNG

    WNG TalkEmount Hall of Famer

    Aug 12, 2014
    Arrid Zone-A, USA
    Will
    In order to have the least added bulk for you adapted vintage lens experience, you'll have to seek out lenses from camera systems with either no mirror box, ie. range finders, or a large aperture prime from an Olympus Pen-F. The Leica L39 mount has a very small 1/2" (12.5mm) thick adapter for E-mount. The Pen-F adapter is even less. I believe the Olympus Zuiko Pen-F 40mm f/1.4 1/2-frame lens will work on the full frame A7.
     
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  6. rayvonn

    rayvonn TalkEmount Regular

    61
    Jan 3, 2016
    Looking back on my question and the answers given, it seems the Takumar was one of the worst cases I could have provided for seeking a thinner adapter given the flange focus distance. I can see though that the best chances of using a thin adapter would be with Leica or Contax rangefinder lenses as well as Canon and to a lesser extent Nikon rangefinder lenses. I really appreciate the responses, including that Olympus tip, many thanks everyone..
     
  7. bobbill

    bobbill TalkEmount Regular

    32
    Oct 27, 2017
    Might be that the Zuiko 1.8/38mm half-frame "normal" is even better with adapter...

    The "screws" with screw mount (all manual) adapters are about as thin as you can get.

    Then there are the C-mount screws, Pentax 110 and Minox-35s but that is taking it too far, IMHO. Image vs equipment aesthetics. Most prefer image, I'd hazard a guess.

    As reminded (by ebits) its always about (flange) distance: 35mm lenses were designed to be just so far from film plane and the Nex and MFT sensors are closer to the front (flange) than the original 35 film plane, so adapted 35mm lenses work.

    Size and weight enter into it also with adapters.

    You go the other way, adapt smaller, say MFT, lens to larger sensor, it does not work as well (vignetting).

    Fairly straight forward. Even I can understand it and I am not much of a photog!
     
    Last edited: Nov 15, 2017
  8. bobbill

    bobbill TalkEmount Regular

    32
    Oct 27, 2017
    FWIW. I bought a Fotasy adapter for Zuiko 38 to E-mount, and the adapter just would not allow lens to lock...price is fabulously right...so I ended up doubling cost for Fotodiox, which worked perfect. For the instant use, cheap and minimal is the charm.
     
  9. WNG

    WNG TalkEmount Hall of Famer

    Aug 12, 2014
    Arrid Zone-A, USA
    Will
    Sorry to read you had trouble with your Fotasy adapter. I went to check mine and a nice positive 'click' upon locking the 38mm f/1.8 onto it. The tolerances are nice and precise, and that's been consistent with every one of my Fotasy adapters. So, this is odd. Inspect the notch in the adapter...that's where it locks with the lens. See if there are any machining burrs that could be preventing the tab from falling in. A few passes with a small hobbyist file will clean and widen the notch. No files? If you have your wife or girlfriend's nail file at your disposal, that could suffice, but she may not be too happy with ya! :)
     
  10. bobbill

    bobbill TalkEmount Regular

    32
    Oct 27, 2017
    Thanks, I just reordered and figure to send back and Rainbow can repair and recirculate...I honestly saw no place to repair, so left it to experts Live and learn.
     
  11. dixeyk

    dixeyk TalkEmount All-Pro

    Jun 18, 2012
    Bellingham . WA
    Kevin
    That's dependent on the lens. The Olympus Pen-F, LTM and Leica M mount are the thinnest I know of. The Konica AR mount is the thinnest of the SLR lens mounts. The M42 that you use for the Takumar is pretty big. Part of the appeal of Konica lenses for me is the fact that the adapter is smaller making attaching an adapted lens to my NEX a bit less cumbersome.
     
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  12. dixeyk

    dixeyk TalkEmount All-Pro

    Jun 18, 2012
    Bellingham . WA
    Kevin
    There's a little spring inside the adapter that you can bend (carefully) with a small screwdriver and that will sometimes fix the lens not locking in problem. I have a few adapters I did that to. It's one of the downsides of cheap adapters.
     
  13. bobbill

    bobbill TalkEmount Regular

    32
    Oct 27, 2017
    Ray, it's all about flange distance, as noted above couple times I believe.

    Distance (short) is why the Zuiko 38mm 1/8 1/2 frame works so well or even the odd Pentax 110 lens - both are physically closer to film (receptor) plane.

    If a 35mm lens or even c-mount movie lens, all have to be "so close or far" from receptor plane. That is it!
     
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