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  1. #1

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    Zorki-4 Slow Rear Curtain Travel

    I've noticed on my 1971 Zorki-4 that the rear curtain travel at speeds of 1/30th and lower appears to be slow. This is especially evident at 1/30th. Sometimes it looks ok but more often than not it seems slow. I tried adding a half turn of extra tension on the rear curtain spring but that did't seem to affect the travel. Any suggestions as to what to check?

  2. #2

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    Quote Originally Posted by Lamar View Post
    I've noticed on my 1971 Zorki-4 that the rear curtain travel at speeds of 1/30th and lower appears to be slow. This is especially evident at 1/30th. Sometimes it looks ok but more often than not it seems slow. I tried adding a half turn of extra tension on the rear curtain spring but that did't seem to affect the travel. Any suggestions as to what to check?
    The camera needs a CLA. Changing curtain tension from the proper settings to compensate for bad lubricants will just cause other problems. Sorry there's no quick fix.

  3. #3

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    Yep. I was afraid that would be the answer. I was hoping that since the fast speeds work fine there may be a simple fix to this, it looks very clean inside, no dust or gunk. I hesitate to do a complete CLA myself yet. I do have a 1962 Zorki 4 I got for $15 that I have been using as a training tool. The front curtain ribbons have come loose from the drum. I have it disassembled and am learning from it but I hesitate to screw around with a mostly working camera just yet. What specific points affect the curtain travel speed and why does it only affect it at slow speeds and not fast speeds? The return spring is the driver and it is tensioned the same regardless. Once the curtain is released to return, it should travel at the same speed from what I can deduce from my "parts" Zorki.

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    Quote Originally Posted by Lamar View Post
    Yep. I was afraid that would be the answer. I was hoping that since the fast speeds work fine there may be a simple fix to this, it looks very clean inside, no dust or gunk. I hesitate to do a complete CLA myself yet. I do have a 1962 Zorki 4 I got for $15 that I have been using as a training tool. The front curtain ribbons have come loose from the drum. I have it disassembled and am learning from it but I hesitate to screw around with a mostly working camera just yet. What specific points affect the curtain travel speed and why does it only affect it at slow speeds and not fast speeds? The return spring is the driver and it is tensioned the same regardless. Once the curtain is released to return, it should travel at the same speed from what I can deduce from my "parts" Zorki.
    The curtain speed is a fixed quantity, it is the same for all shutter speeds. Unless you have instruments to measure curtain travel time and shutter speed (effectively, slit width) you can't really tell what's going on, except by making test exposure - a crude method at best. If you can actually see that the curtain is sluggish, it's way out of whack. What may effect it at slow speeds (large slit width) would be poor lubrication in the drum and roller (under the shutter speed dial) and associated timing mechanisms.

    These shutters are pretty simple once you understand the theory and get used to working with smallish mechanisms. Keep practicing, you'll be fabricating your own curtains in no time!

  5. #5
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    Sometimes I find an amazing number of film chips buried under the restricting gear in the bottom of the shutter crate in FED/Zorki cameras.

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    Quote Originally Posted by limnidytis View Post
    Sometimes I find an amazing number of film chips buried under the restricting gear in the bottom of the shutter crate in FED/Zorki cameras.
    Yes - I should have mentioned to check for debris first!

  7. #7

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    What specific type of oil should I use for the shutter timing mechanisms (top) and the curtain drum shafts and winding gears?

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    Quote Originally Posted by Lamar View Post
    What specific type of oil should I use for the shutter timing mechanisms (top) and the curtain drum shafts and winding gears?
    Use a high quality light clock or watch oil, the modern synthetic oils will last for quite a few years and oils suitable for cold weather are available. But, putting oil on without cleaning the lubrication points is pointless, the new oil will be contaminated by the remains of the old oil and any dirt/abrasive contamination, also it will probably creep away leaving the parts dry. A couple watchmakers oilers can be had for $10 or less; putting too much oil on is as almost bad as none. Some points require only the slightest dot of oil (get a 2.5 - 5x loupe so you can actually see how much you apply) and other parts must be left dry. Gear teeth are typically left dry - there is no sliding contact between well cut teeth, and in a camera no inertial loads (resulting from high rotative speeds) that need cushioning by a lubricant film. Use a light grease on the gear pivot points.

    For evaluative purposes - to free sticky parts so you can verify proper operation/ troubleshoot problems - "Break Free CLP" is a useful product, it will get things moving - but it is not a substitute for proper cleaning and lubrication.

    Edit - one source for high quality oils, oilers, etc - http://www.ofrei.com/page246.html
    Last edited by E. von Hoegh; 01-07-2014 at 11:12 AM. Click to view previous post history.

  9. #9

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    The slow speeds are controlled by a clockwork escapement, not travel times. In Leica M cameras it's inside the camera at the bottom. Cleaning and relube is the correct answer.

    Since you've got the other camera apart you should have a clear view of the offending assembly. Naptha or liquid lighter fluid to clean it and watch oil for lubrication. The oil should be crystal clear, If it has a color to it, it's too heavy.

    the pivots of the gears and pallet are what need the attention. A pinpoint oiler will apply too much lube, Use the oiler and transfer a small drop to a sewing needle or straight pin and apply it by touching the pin to the pivot.
    Heavily sedated for your protection.

  10. #10

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    Quote Originally Posted by John Koehrer View Post
    The slow speeds are controlled by a clockwork escapement, not travel times. In Leica M cameras it's inside the camera at the bottom. Cleaning and relube is the correct answer.

    Since you've got the other camera apart you should have a clear view of the offending assembly. Naptha or liquid lighter fluid to clean it and watch oil for lubrication. The oil should be crystal clear, If it has a color to it, it's too heavy.

    the pivots of the gears and pallet are what need the attention. A pinpoint oiler will apply too much lube, Use the oiler and transfer a small drop to a sewing needle or straight pin and apply it by touching the pin to the pivot.
    Whether the Zorki has slow speeds and therefore a governor or not, I don't remember. But said governor controls when the curtain is released, not the speed of travel; it wouldn't effect the shutter at all at full gate speed which is 1/30. And, a drop on the end of a straight pin is far too much for any pivot in the slow speed geartrain, indeed it would possibly be too much oil for the bushings in the curtain drums. The pallet pivots are lubricated, the pallet proper and pallet wheel teeth are not unless the maker specifically recommends it.

    Edit - for clarity.

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