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Thread: very tight focus on lens: repair ?

  1. #1
    PeterLeyssens
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    very tight focus on lens: repair ?

    Hi,

    I just received a Schneider Kreuznach 25mm/f1.4 C mount lens for my future E-P1 in the mail. I bought it from an eBay seller that I saw mentioned on this forum and who frequently has a very large choice of lenses. However, the focus ring is extremely stiff. I don't have a camera to mount it on, but trying to turn it off-camera, it's extremely hard to get it from infinity to closest focus and back. Somewhere halfway, it gets really stiff.

    I don't think the problem is caused by a knock: it was very well wrapped and cosmetically as well as optically, it looks really good. I'm quite sure it'd make a good lens, so I'm reluctant to ask my money back.

    Is this a lens that should get a CLA to make it perfect ? Is this something I could do myself, and if so, what do I need ? If not, does anybody know a good repair shop in Belgium ?


    Peter.

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    Re: very tight focus on lens: repair ?

    Tight focus would be the least of my concerns, if I want to use this on the E-P1.

  3. #3
    PeterLeyssens
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    Re: very tight focus on lens: repair ?

    Vivek,

    What do you mean ?


    Peter.

  4. #4
    daggerlee
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    Re: very tight focus on lens: repair ?

    You might be able to remove the c-mount and add some grease/oil yourself to the mechanism. Be careful you don't screw up the focusing range like I almost did.

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    Re: very tight focus on lens: repair ?

    Peter, Does this lens cover the 4/3rds sensor? That would be the major concern for me.

    Besides, I would not find it easy to focus with this lens on the E-P1.

    Have you checked the focus after mounting it on a C-mount adapter or you just tried holding the c-mount and tried the focus? If it is the latter then you are worrying yourself unnecessarily. If I were you, I would not tinker with it.

  6. #6
    PeterLeyssens
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    Re: very tight focus on lens: repair ?

    Hi Vivek,

    I checked the database and it should cover the sensor. If it only covers 16mm, I was planning to use it as a lens for square format (13x13 is just over 18mm diagonal, so most 16mm lenses should cover that).

    I haven't checked the lens on a body yet, but there is some very serious resistance halfway while rotating the focus dial. I've tried this before with other lenses and while it is obviously much harder to rotate the dial off-camera, this lens is is quite extreme.

    I've contacted the seller and he says there is no problem, I can get a refund. But with decent c mount lenses getting expensive (and they're quite hard to find, too), I might want to take a look at lubing it myself. Any suggestions on what to use for it ?


    Peter.

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    Re: very tight focus on lens: repair ?

    Any suggestions on what to use for it ?
    Peter, Did you try focusing after mounting it on a c-mount? This is important.

    I would use a hair dryer to gently warm it up and try focusing back and forth a few times (mounted in an adapter). This may loosen it up.

    Nothing further unless you are capable/confident to dismantle the whole thing, wash the helicals with petroleum ether, dry it and grease it with a suitable grease (just the right amount).

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    Senior Member petermcwerner's Avatar
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    Re: very tight focus on lens: repair ?

    Nothing further unless you are capable/confident to dismantle the whole thing, wash the helicals with petroleum ether, dry it and grease it with a suitable grease (just the right amount).
    I have a worse problem with a Speed Panchro in Arri Mount I bought from Russia whose focusing ring does not turn at all on or off camera. I do NOT consider myself capable/confident to dismantle it. Would somebody know/recommend a technician who could do the work at reasonable cost?

    Thanks
    Peter (Werner)
    Peter Werner
    Leica M8, R9+DMR & Digilux 2; Nikon D700; Panasonic FX01, FX150 & G1; Samsung TL350 (WB 2000)

  9. #9
    PeterLeyssens
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    Re: very tight focus on lens: repair ?

    Quote Originally Posted by Vivek View Post
    Peter, Did you try focusing after mounting it on a c-mount? This is important.
    I haven't yet. My c mount adapter has just arrived today, but I still have no camera to mount it on... with its 10M people, Belgium may not be the first country on Oly's mind when shipping out new cameras

    Quote Originally Posted by Vivek View Post
    I would use a hair dryer to gently warm it up and try focusing back and forth a few times (mounted in an adapter). This may loosen it up.

    Nothing further unless you are capable/confident to dismantle the whole thing, wash the helicals with petroleum ether, dry it and grease it with a suitable grease (just the right amount).
    I found some screws on the mount of the lens, but I couldn't get them to move. Instead of trying harder and damaging the screws, I decided to return the lens and to get my refund. Shame about the shipping costs, but that's life.

    Thanks for your help,


    Peter.

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    Re: very tight focus on lens: repair ?

    The camera is less important than having the lens in the c-mount to try the focus stiffness. This is simply because the c-mount is so small to hold it while focusing!

    Too bad that you did not mount the lens while trying for the focus stiffness.

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    Re: very tight focus on lens: repair ?

    I have a local guy here outside of Philly who is extremely good at working on overhauling and repairing old cine lenses. I'm sending him an ektar 40mm/1.6 that has a rock solid focus ring and he says he can get it working again. Also, Stefan is sending him c-mount lenses to get repaired this week too!

    His name is Steve Serrota and he truly knows his stuff. He used to work for Schneider. I found out about him when I had to look around for a guy who could repair my Schneider zoom which has a lot of elements. He was one of the few who knew how to do it and for a reasonable cost. You can check out his website at www.cameracare.com or reach him at (215) 470-2198. You can mention that I referred you to him (Gary San Angel).

  12. #12
    PeterLeyssens
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    Re: very tight focus on lens: repair ?

    Quote Originally Posted by Vivek View Post
    The camera is less important than having the lens in the c-mount to try the focus stiffness. This is simply because the c-mount is so small to hold it while focusing!
    Oh, that's what you mean. I think I tried it in a decent way, though, not by holding the mount. The lens has two rings about half a centimeter wide, with half a centimeter between them: focus and diaphragm. So I could turn the diaphragm all the way to one side and hold the lens very well while trying to turn the focus. The problem was never that it was too hard to hold the lens: the focus was really tough and I felt a kind of grinding inside, probably the grease that has stiffened up. I could still try the hair blower trick. If it works, will I have to do it regularly ?

    (I still have the lens, as I can't read the seller's address and she hasn't answered my mail about this, so I can still try it).


    Quote Originally Posted by gmoe View Post
    I have a local guy here outside of Philly
    Gary,

    Very kind of you, but shipment to/from Philly from where I live (Belgium) would be quite expensive !


    Peter.

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    Re: very tight focus on lens: repair ?

    Quote Originally Posted by gmoe View Post
    His name is Steve Serrota and he truly knows his stuff. He used to work for Schneider. I found out about him when I had to look around for a guy who could repair my Schneider zoom which has a lot of elements. He was one of the few who knew how to do it and for a reasonable cost. You can check out his website at www.cameracare.com or reach him at (215) 470-2198. You can mention that I referred you to him (Gary San Angel).
    fwiw, the link points to a shop in spokane, not philly

  14. #14
    daggerlee
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    Re: very tight focus on lens: repair ?

    Quote Originally Posted by gmoe View Post
    I have a local guy here outside of Philly who is extremely good at working on overhauling and repairing old cine lenses. I'm sending him an ektar 40mm/1.6 that has a rock solid focus ring and he says he can get it working again. Also, Stefan is sending him c-mount lenses to get repaired this week too!

    His name is Steve Serrota and he truly knows his stuff. He used to work for Schneider. I found out about him when I had to look around for a guy who could repair my Schneider zoom which has a lot of elements. He was one of the few who knew how to do it and for a reasonable cost. You can check out his website at www.cameracare.com or reach him at (215) 470-2198. You can mention that I referred you to him (Gary San Angel).

    I've heard about this guy on photo.net but read some not-so-satisfactory reviews about him

  15. #15
    Senior Member petermcwerner's Avatar
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    Switar lens repair

    A bit OT, but perhaps interesting for whoever may have problems with Switars. I did not realize Bolex still exists as a firm. They build cameras to order and assure support, repair and spare parts for older Bolex equipment. I have a C-mount 26mm/1.1 Switar whose diaphragm is blocked, so today I drove to Yverdon, half an hours drive from home and they will fix it. They told me that good ones are worth $2000-3000 as there are very few of them around and they cover Super 16. I shall keep you informed.

    Cheers
    Peter
    Peter Werner
    Leica M8, R9+DMR & Digilux 2; Nikon D700; Panasonic FX01, FX150 & G1; Samsung TL350 (WB 2000)

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    Re: very tight focus on lens: repair ?

    fwiw, my switar 26/1.1 is being tweaked at a bolex repair shop
    and they're adjusting the focus for standard c-mount flange
    distance vs rx flange distance (while doing other repairs).

    might be worthwhile doing while it's in the shop!!

    cheers,

    lcubed

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