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Thread: Back Focus- 75 Summarit

  1. #1
    Senior Member Jason Muelver's Avatar
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    Back Focus- 75 Summarit

    Hey everyone. Looking for some help here.

    I picked up a demo lens off eBay (yeah, I know) that is 100% gorgeous except for a major back focus issue.

    Anyone here have contacts at Leica to get this fixed quickly? I was quoted 4-6 weeks and I'll have 4 weddings in that time frame.

    Focus point is the lower U2


    Focus point is the "Y" in New York Times
    http://jasonedwardphoto.com http://jasonmuelver.tumblr.com
    Nikon FX, Leica M8, Mamiya 645, Canon F-1

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    Workshop Member glenerrolrd's Avatar
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    Re: Back Focus- 75 Summarit

    The standard turnaround for almost anything in NJ is 4-6 weeks . Believe me they aren t checking anything ....they just use 4-6 weeks as a reasonable estimate of when the shop will get to it.

    You have three choices..
    1. call DAG tomorrow morning around 8 30am to 9am CST ...then beg a lot . He will deliver on whatever he promises. Pay for express mail both ways .

    2.Call Leica and ask to speak to the person that handles professionals and see if you can qualify as a professional user and if they can give you a fast turnaround.

    3. Find another lens to use.

    I have been there dozens of times ..new equipment ,old equipment ....wedding,once in a life time trip ..same answer .

    Actually I would call DAG right now you still have an hour .

  3. #3
    Senior Member Jason Muelver's Avatar
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    Re: Back Focus- 75 Summarit

    Roger,

    Thanks for the reply.

    I actually fired off an eamail to DAG right before you replied.

    I tried the professional route at Leica and didn't get anywhere.

    If I don't hear back via email by mid-day tomorrow, I will call.

    Appreciate the comment!
    http://jasonedwardphoto.com http://jasonmuelver.tumblr.com
    Nikon FX, Leica M8, Mamiya 645, Canon F-1

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    Workshop Member glenerrolrd's Avatar
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    Re: Back Focus- 75 Summarit

    Jason

    Don t wait DAG prefers a call and early in the day is best . Emails see to have lower priority. He has always tried to help me but sometimes he just can get thru the work. He will tell you but you have a better chance if you call him.


    Quote Originally Posted by Jason Muelver View Post
    Roger,

    Thanks for the reply.

    I actually fired off an eamail to DAG right before you replied.

    I tried the professional route at Leica and didn't get anywhere.

    If I don't hear back via email by mid-day tomorrow, I will call.

    Appreciate the comment!

  5. #5
    Senior Member Jason Muelver's Avatar
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    Re: Back Focus- 75 Summarit

    Roger,

    I swear you and Don have some weird synching going on! He emailed me about 5 min before your reply!

    This is what I'm weighing out. I am covered under warrantee because even though I bought it off ebay, it's from an authorized seller and Leica honors the glass for 1yr since it's a demo. 4-6 weeks... maybe.

    DAG said about a week and he'd tweak the rangefinder and I'd probably toss in my 40 Nokton to tune as well.

    Free vs. a few big bills.

    I'm leaning towards the price of perfection.
    http://jasonedwardphoto.com http://jasonmuelver.tumblr.com
    Nikon FX, Leica M8, Mamiya 645, Canon F-1

  6. #6
    Senior Member Jason Muelver's Avatar
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    Re: Back Focus- 75 Summarit

    I guess I figured out the cheat a little---

    http://jasonedwardphoto.com http://jasonmuelver.tumblr.com
    Nikon FX, Leica M8, Mamiya 645, Canon F-1

  7. #7
    jqberry
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    Re: Back Focus- 75 Summarit

    I hope you get everything sorted out. I am actually surprised to find out that even Manual Lenses do the back focus problem thingy. Always thought it was on AF only. Sorry from the Nikon Camp! haha, learn something new everyday

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    Re: Back Focus- 75 Summarit

    The quickest way to hack a fix for back-focus is to build up the RF cam of the lens a little bit. One layer of copper tape on the RF cam is usually enough to correct back-focus of the amount displayed here.

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    Senior Member Jason Muelver's Avatar
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    Re: Back Focus- 75 Summarit

    Brian... thanks! I've been too busy to send the lens to Leica or DAG.

    Copper tape? Never heard of it, but Im sure going to look!

    Any "how-to" specifics?
    http://jasonedwardphoto.com http://jasonmuelver.tumblr.com
    Nikon FX, Leica M8, Mamiya 645, Canon F-1

  10. #10
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    Re: Back Focus- 75 Summarit

    I use 3M copper tape, had some left over from the lab bench. It is thin, and does not compress. Some of my lenses have had it on for years. I use one layer with my 50/1.1 and 35/1.2 for the Leica M9 to stop back-focus.

    http://solutions.3m.com/wps/portal/3...beRQ89J1RQDXgl

    Example use on an Industar-61L/D:



    A strip of the tape on the upper right on the camera.



    I would check the hardware store, some metallic tape is used for decoration and trim.

  11. #11
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    Re: Back Focus- 75 Summarit

    Ebay. Who would have thought...

    http://cgi.ebay.com/3M-1181-EMI-Copp...item2c5bffe16f

    Random example searching for "3M copper tape"

  12. #12
    Senior Member Jason Muelver's Avatar
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    Re: Back Focus- 75 Summarit

    Is there a technique to it? Or just put a piece anywhere on the cam ring?

    Thanks so much!
    http://jasonedwardphoto.com http://jasonmuelver.tumblr.com
    Nikon FX, Leica M8, Mamiya 645, Canon F-1

  13. #13
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    Re: Back Focus- 75 Summarit

    I have not worked on a 75/2.5 before, and RF cams come in two flavors.

    The easiest is a cam that does not rotate. For that type, put a later on the portion of the cam that lines up with the RF cutout of the mount. The I-61 as shown does not rotate, and is this type. The Copper tape aligns with the cutout on the LTM to M adapter I use.

    For cams that rotate: If the problem with focus is the entire range: you need to make a layer to cover the cam as it totates from infinity to close-focus.

    If the error is only on close-ups, rotate the lens to the close focus, and put a layer of tape where the Cam lines up with the cut-out. Line the Cam for as far as you thing the focus is off. This provides a "cheap" indexed-cam.

    Nice thing about the tape, you can pull it right off if you choose to later get the lens services. Or- as I have done, "it works, and if it ain't broke no need to fix it".

  14. #14
    Senior Member Jason Muelver's Avatar
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    Re: Back Focus- 75 Summarit

    So a strip along the entire cam? Hmm.... Give it a try.

    Now to find the tape locally.
    http://jasonedwardphoto.com http://jasonmuelver.tumblr.com
    Nikon FX, Leica M8, Mamiya 645, Canon F-1

  15. #15
    Senior Member johnnygoesdigital's Avatar
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    Re: Back Focus- 75 Summarit

    I just rented a 90mm, f/2 APO, for a corporate shoot. No time to demo the lens as it was delayed by the dealer. The lens also back focused even though I was told it was checked prior to shipping. From these posts, I assume that each individual camera should be "shimmed" ? Also, the 75mm f/2 would have been a better choice, given the the group shot in a tight location!

  16. #16
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    Re: Back Focus- 75 Summarit

    What I've noticed with the M8 and M9- pixel peeping allows you to see focus errors that are masked by film. Manufacturers make assumptions when setting the shim for lenses, like film curvature and the F-stops that the lens is most likely to be used.This week I tried two 5cm F1.5 Summarits on the M9: both front-focused at F1.5 but were perfect at F2.8. The lens was optimized for best performance at F2.8, a compromise.

    Nikon lenses were known for optimizing for wide-open work. I've used the Nikkor 8.5cm F2 and the Nikkor 10.5cm F2.5 on the M9. Both are perfect wide-open and close-up.

    Nikkor 10.5cm F2.5, wide-open.



    another.



    The entire series was spot-on, first time using the lens on the M9.

    Same with the Nikkor 8.5cm F2. Perfect wide-open and close-up.



    So whatever assumptions that Nikon made in the 1950s, they hold true for the M9.

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