Can I mount my Minolta Rokkor 20-80mm f/2.5 zoom lens?

Discussion in 'Adapted Lenses' started by RDM, Jan 6, 2011.

  1. RDM

    RDM Mu-43 All-Pro

    Originally i asked this question on another forum site that I always go to for my photographic related questions, but there was no one that knew anything about this lens and i was directed here.
    I got a Minolta Rokkor 20-80mm f/2.5 TV zoom lens "for S.V. color".
    Does anyone know anything about this lens?
    It is not a C-mount lens , because those are a 25mm screw thread mount. Instead it has a 30mm screw thread mount.
    I have no idea what the flange back, image register distance it is. I wish i knew the distance because i am wondering if i can get this mount converted. Since the rear element is not in the thread mount like many C-mount lenses i believe the entire metal mount can be removed and replaced with something else.
    Does anyone know of Lens technicians that change mounts on C-mount lenses to m4/3 or the NX10 or the like?
    I am thinking this might make a very good lens for an Olympus pen or if the distance from rear lens element to image plane is long enough , it would be ideal to use on the NX10. However i have no idea who would be able to tell me the flange back to image plane distance , or who would be able to figure it out , let alone be able to convert the mount.
    I have yet to purchase a digital camera, but I have to soon. I have a budget of about 500. Whatever i get i plan to use all the Rokkor and MD mount lenses i have and, I been leaning towards a used NX10 because of its larger sensor and form factor. However I do like the in body IS of the Olympus but not the fact i need to pay extra for an EVF. I thought if this lens could be converted to one of those mounts that would be something to factor in.
    Any help would be much appreciated.

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  2. RDM

    RDM Mu-43 All-Pro

    OK, Since i got no responses at all, maybe I was too confusing earlier.
    How about this.. Who out there Does lens mount conversions? For instance, C-mount to µ4/3.
  3. bilzmale

    bilzmale Mu-43 All-Pro

    This page may help. LINK:

    Oh! and welcome to the forum - the :43: system is pretty friendly for legacy lenses. Hope you stick around.
  4. apicius9

    apicius9 Mu-43 Veteran

    Feb 1, 2010
    Honolulu, Hawaii
    Sorry, I can't really help, but if you find someone who does conversions well and cheap, please let us know ;) I have never seen that mount in 30mm either, have you thought about contacting directly?

  5. RDM

    RDM Mu-43 All-Pro

    Thanks Bill, I hope so too. I still have never purchased a Digital camera yet, But it also depends on what i can afford to purchase and use with all my Legacy glass. I still love and use film, both B&W and color about the same , since i tend to find color film pretty inexpensively. SO i have the Misfortune of Having invested over the years in both Minolta MD (mostly) and Canon FD mount systems and lenses. Both orphans and only DSLRs adaptable to is the 4/3 system.
    In the mean time i wanted to see how usable this lens i happen to have was. I looked again earlier and the rear element inside the mount is slightly larger in diameter than the inner diameter of the mount and and i used a caliper to measure about 14mm of distance from it to the end of the mount threads.
    Heck i also just though since the different between the Digital pen and the Pen-F mount was only 8.95mm maybe i can find someone that would make it to a PEN-F mount. That would be interesting. Man i wish i had equipment to test this lenses Flange back focal register distance and image circle.

    Anyway , thanks for the info. I am not looking for adapters. I am looking for the mounts to get converted. Since it would be better for the lens to be able to cast the largest image circle possible , and without the restriction of the mount hole. Wich would definatly cause vignetting seeing how the rear element is so far forward from the mount.
    In the past I seen on eBay many times lenses for sale that had the mounts from c-mount lenses converted to µ4/3 and even LTM or LM mounts. An many other lense mountss converted to other type of mounts. SO i know its possible and there are people out there that do it . I just wanna find

    Yea I did, but I also know that they no longer have anything to do with cameras. Their camera division was bought out by Sony as you know.. I also heard stories from other older KM camera users trying to get info on their cameras and hitting many brick walls. I'm told finding out from them about anything pre-digital is a lost cause so decided not to try.
  6. texascbx

    texascbx Mu-43 Veteran

    Dec 30, 2009
    I directed you here my friend. Good luck.
  7. RDM

    RDM Mu-43 All-Pro

    Thanks Tex.
    So far i got bupkis. None even knows of places that do mount conversions, and i know they exist, i just cant find them. I think i might have to do it myself. I'm now an Engineering graduate and know how to CAD up plans for mechanical details. I should be able to design a mount. I just need to figure out the Flange Focal distance and do some measuring Which means borrowing or buying some tools. Then finding a place that would do the Fabrication.
    Would be easier if i could get a hold of just the µ4/3 side of a mount from an adapter. I see many of the Aluminum ones for sale on eBay Cheep but I want a Brass/Chrome one and they are all used on the more expensive adapters.
  8. RDM

    RDM Mu-43 All-Pro

    Yeay, got a G1 .. updater on the Lens too

    Thanks to some good Samaritan who read a posting of mine on another photo forum site, I was able to afford to purchase a G1. Apparently he did not like the way (i am quoting him) "some pompous egotistical idiot was talking to" me in a question thread i started. The guy was telling me to spend more money and get a g1 after i told him on the auction site i been looking on had none in my budget range. HE then proceeded to just be insulting and also lied saying he recently had a friend buy one for like 168 dollars or something around there, when in fact that no G1 sold for even close to that much when you look at the closed listings for the past 4 months.
    Well like me he knew the guy was full of it and just trying to instigate something and searched that too , and rather than comment in the thread sent me a message and expressed his condolences for having to deal with a member like that and offered me some assistance to this poor struggling college student.

    He PayPaled me a little money which afforded me to purchase the camera and adapter . The camera came in a day but I am still waiting on the adapter. I might have to bite the bullet and go buy one At a camera store in the city, like Adoroma and put it on a credit card and hope for money i wonder if i can return it tho when the other arrives?

    Anyway the cool thing was that i grabbed the lens i was talking about above, and just held it up to the flange of the G1 an took some photos , it was very interesting.

    I think i was holding the lens a little cockeyed because the left side is sharer than the right, but it looks like this lens would be usable if I can get a mount for it . I spoke to the professor at the machine shop at college and after explaining things to him he said we can just try and drill open a C-mount adapter and tap the new 30mm hole.

    SO as soon as I finish paying off my paypal credit account and know i can get money to buy one, i will try this .. I guess i will have to wait a while.

    Sorry for the uninteresting subject choice for the photo. wow i need to clean my Kitchen :(

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  9. RDM

    RDM Mu-43 All-Pro

    This photo is a little more interesting.

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