Zorki 4 rangefinder alignment

[ballfresno]

Hello,

I've essentially been a lurker for while... I have owned a Canonet (G-III QL19) for a while but today I fully joined the RF community by acquiring a Zorki 4 ('68 vintage). I took a set of shots today but haven't finished the film yet so don't know if there are leaks etc.

However, what I do know is that the lens and rangefinder are out of synch. If I use the RF at a very distant object (>100m), the lens indicates that the object is 5-7m away! The lens is an Industar 50/3.5 in case that matters.

My questions are (a) does this definitely indicate a problem with the RF and (b) if so, can I fix this myself?

I've tried searching this forum for appropriate threads but have found nothing although I did find one thread which made reference to there being a thread on this issue... (sigh).

cheers,
eric

 

[Kim Coxon]

It could be one of 2 possible problems. The RF could be out or someone has done a relube job on the lens and reassembled it on the wrong thread. Take a photo of a distant object with the lens set to infinity. If the picture is in focus, the RF is out. If the picture is out of focus, I would suspect the lens. Alternatively, try to borrow another lens known to be good.

Kim

 

[burninfilm]

I found your info:

http://www.rangefinderforum.com/forums/showthread.php?t=7878&highlight=zorki+rangefinder+infinity

Took me all of 2 minutes to look it up. I need to do the same thing on a Mir!

 

[Nickfed]

Hello,

However, what I do know is that the lens and rangefinder are out of synch. If I use the RF at a very distant object (>100m), the lens indicates that the object is 5-7m away! The lens is an Industar 50/3.5 in case that matters.

My questions are (a) does this definitely indicate a problem with the RF and (b) if so, can I fix this myself?

Coxon could be right but you can make some simple checks before you reach for the screwdrivers. The first thing to do is to check the position of the rotating part in the body

First move the lens in and out to infinity and 1m. It should stop with a positive bump in both cases, i..e not feel like you are screwing a bolt down to its limit, and the scale should be exactly at infinity when it is screwed in.

If you do get a bump in both directions, then screw the lens out again, i.e. to focus close, and you should see that the back of the lens is more or less flush with the back of the body. If this is the case, then it is most likely that the scale ring is not prperly located. Loosen the three little screws and rotate it to infinty with the lens screwed in.

Assuming you have the solid I-50, set it to infinity and check how far the black bit pokes out. It should be 3.5mm. You should be left in no doubt about this and if you don't have a proper instrument to measure it, you can use a piece of cardboard as a gauge and measure that with an ordinary ruler. If the lens is out by one start, I believe the error is over 0.5mm!

The drawing shows what you want see. The other dimension shows 7.5mm from the cam to the shoulder that bears against the mounting flange on the camera. This dimension applies to all LTM lenses when set to ininity.

The lens has a four start thread and, if the scale is located properly, it could be out by one start. It is easily fixed. See this post for more details:
http://www.rangefinderforum.com/forums/showthread.php?t=10633&highlight=clean+lube+industar

Another problem could be a sticky RF follower but I'm more inclined to be suss about the lens.

 

[ballfresno]

Thanks Kim, burninfilm and Nick!

I've shot a test roll already and should have results on Monday or Tuesday.

In the meantime, I've checked the lens as you suggest, Nick, and the focus ring bumps up against the limits correctly. However, the protusion at the back looks larger than 3.5mm but I'll have to wait until I get home to measure it properly. I'll post again then.

Thanks again all!

eric

PS - for burninfilm, I fogot to include "infinity" in my search... 🙁

 

[ballfresno]

If you do get a bump in both directions, then screw the lens out again, i.e. to focus close, and you should see that the back of the lens is more or less flush with the back of the body. If this is the case, then it is most likely that the scale ring is not prperly located.

If you mean that the moving part of the lens lines up essentially with the non-moving screw part of the lens, this is definitely the case.

Assuming you have the solid I-50, set it to infinity and check how far the black bit pokes out. It should be 3.5mm.

I've measured and it definitely looks like 4mm to me so I guess this means the focus ring must be out by one start? Mind you, I don't know what a solid vs non-solid version of this lens might be... but I guess mine is indeed solid.

In any case, everything you say convinces me of this so I'm off to try fixing using the instructions you pointed me to which although scary (to somebody as clumsy as me) seem straightforward enough... now if only I could find a screwdriver small enough!

Thanks again!!

 

[Nickfed]

If you mean that the moving part of the lens lines up essentially with the non-moving screw part of the lens, this is definitely the case.

Yes. The entire lens assembly rotates in a barrel that screws into the camera. When focussed on 1m the black part at the back is essentially flush with the outer barrel

I've measured and it definitely looks like 4mm to me so I guess this means the focus ring must be out by one start? Mind you, I don't know what a solid vs non-solid version of this lens might be... but I guess mine is indeed solid.

Correct. The lens assembly is likely to be out by one thread. Some I-50s are collapsible, some not. I believe the collapsibles may be more common on earlier Zorks

In any case, everything you say convinces me of this so I'm off to try fixing using the instructions you pointed me to which although scary (to somebody as clumsy as me) seem straightforward enough

Not much can go wrong. Work over a big dish so you don't lose the screws.

 

[Spyderman]

Before disassembling anything try this http://rick_oleson.tripod.com/index-123.html

 

[ballfresno]

Thanks for the link, Spyderman. Will try it out.

In any case, I got my test roll back and at least the rest of the camera works (i.e. no apparent leaks, shutter speeds and aperture control okay, ...). Most of the photos I took came out just fine as I used Ilford's XP2 (iso 400) on a sunny day so ended up at f/8 or smaller most of the time. Here's one example:

 

[ballfresno]

Update: focus works fine now

Update: focus works fine now

Just to update you all. The lens was fine but the rangefinder needed adjustment. I've adjusted for both close focus and infinity focus and it now seems to work very well. Probably needs some slight adjustment yet but I'm getting there.

Photos attached were taken yesterday.

Thanks all for your pointers and advice!