Focus Problem on Zorki 4

[rigtenzin]

I just received a Zorki 4 from an ebay sale. It appears something is wrong with the focus. The two images that appear for focusing do not ever line up vertically. I can get them to line up horizontally by adjusting the focus ring as expected.

My previous rangefinder experience is with a Yashica GSN and it has always lined up vertically.

Is this something that can be adjusted on the Zorki?

Thanks,
Rob

[Oldprof]

Welcome to the RF Forum Rigtenzin. For instructions for Russian rangefinder adjustments go to the following website and follow the links:

http://www.btinternet.com/~stowupland/index.htm

[pvdhaar]

Just a note before you start changing anything to your camera. When I move my eyes up and down even a little bit when looking through the VF of my Hexar-RF, I see the two images either vertically aligned or not.

Maybe in your case it's indeed a matter of different viewfinders on different cameras that require a different position of the eye. Whether it applies or not, it's cheap and easy to check...

[rigtenzin]

Update from Original Poster:

I checked out the website that Oldprof recommended. Thanks. It 's a great website. I find some of the websites related to rangefinders are as interesting as the cameras themselves -- lots of personality.

I found another: http://rick_oleson.tripod.com/index-58.html

This site has nice part breakdown drawings and photos of FEDs and Zorkis.

Last night I removed the top cover from my Zorki 4 and tried to adjust the rangefinder mechanism. I can only find a horizontal adjustment. If I've got it right, it's the screw that is hidden by a cap screw.

Where is the vertical adjustment on the Zorki? From what I've read, the FEDs can be vertically adjusted by turning the RF diopter. The Zorki 4 doesn't seem to have that ability. Any suggestions?

My next step is to take a photo of the assembly and post it for others to see and give recommendations.

Thanks,
Rob

[pshinkaw]

Take a very close look at the rangefinder window closest to the centerof the camera. Under the top there should be a small round lens surrounded by 2 concentric rings. Each ring shiould have a set of tiny spanner slots.

If this is not visible, it may be covered by shellac or other gunk. Clean it by applying denatured alcohol or Everclear and scraping the rim gently with a toothpick.

Rotating the the inner ring within the outer ring will move the image. It is not actually a pure vertical movement. You are actually moving the image in two partially overlapping circles. If you rotate them too much, they will cease to overlap and the images will never coincide. Also, since they are circles, Once you get the vertical lined up, you will have to reset the horizontal.

Typically this set-up is very dirty and hard to see. Be patient and don't use any tools which will scratch or bend.

Remember too that the the principal rangefinder adjustment on a Russian camera is the pie-shaped cam behind the lens. The screw adjustment is only the infinity limiter.

-Paul

[rigtenzin]

I corrected the rangefinder alignment last night with your help. I removed the top cap again to expose the RF window. I could then see two slots around the RF window glass. I used a pair of tweezers to rotate the glass and correct the vertical alignment.

I then went back to work on the horizontal alignment. It appears to be correct now also.

I'm going to make a takeup spool tonight and load it with film.

Thanks,
Rob

[rigtenzin]

By the way, I couldn't find anything to adjust on the pie-shaped cam behind the lens. I found it and saw how it works, but I couldn't figure out how to adjust it. However, the screw adjustment seemed to do plenty as far as adjusting the horizontal alignment. For example, just a quarter of a turn makes a huge difference.

I'm probably missing something -- let me know if you have any suggestions.

Thanks again,
Rob

[pshinkaw]

Glad you figured oit out. Here are my thoughts on the cam...

The rangefinder coupling cam ( wedge-shaped) on Russian rangefinders is a very innovative and low cost approach to the finer engineering and machining skills of E. Leitz. Leitz uses a roller cam in the Leica. The roller gives smoother operation and a constant radius. Therefore it must be made very precisely. As a result the Leica needss only 2 rangefinder adjustment parameters, vertical and horizontal.

The Russian rangefinders have 3 parameters, vertical, horizontal-infinity and horizontal-near. The horizontal-near parameter is set by turning the wedge shaped cam. The cam has a variable radius, and this radius can be change by swiveling it on its base.

Some brave souls with steady hands use a pair of needle-nose pliers with rubber tips, or smooth (toothless) needle-nose pliers. Isaak Maizenberg recommends making a specialized but simple wrench to do the job.

I took a piece of photo-matte board and cut into a strip about 0.5 inches by 2 inches. I then drew the shape of the cam on one end and cut it out with a sharp Exacto knife. After doing this, check the fit on the cam.

If it fits, use this matte board wrench as a template and trace the outline on a piece of Lexan or Lucite about 3/32-1/8 inch thick. Cut the hole out. You now have a wrench.

Don’t make the wrench any wider than you need to accommodate the cut-out. If it is too-wide, it will not be able to move enough within the lens mount throat.

Focus the camera on a near object. Some people use 1 meter. I prefer to use a distance closer to what I ordinarily shoot at like 5 meters. Notre were the secondary image lies at this distance.

I am right-handed. To adjust the cam, remove the lens and hold the body in your left hand, upside-down. Use a fine tip permanent marker and put a reference mark on the top of the cam. This will allow you to see how much movement you are creating. Place the wrench over the cam and turn it, one way or another. Replace the lens and refocus. If the image moved farther apart, turn the cam the other way. Different positions have different radii, and so if you cannot get it to focus at one end of the cam, try the far end or the middle.

Sometimes the cam is loose or becomes loose during adjustments. In that case I use a dab of shellac on the pivot to tighten it up.

The usual progression to follow is as follows:

1. Set vertical image 2. Set near image 3. Set infinity image, 4. recheck near image, if it has to be moved again, follow-up by checking infinity image again, and so on.

Sometimes, no matter how hard you try, these Russian rangefinders will not agree between infinity and near focus. In that case, I opt to set the rangefinder for the best near focus and rely on depth of field for the infinity focus. This usually works well because infinity has lock.

-Paul