Rangefinder Calibration (at infinity)

punkzter said:
Does anyone have a link or brand recommendation for the special screwdriver?
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My screwdriver is not a special screwdriver, only it's head is beveled and polished to fit perfectly into the groove (slot) on the underside of the eccentric wheel that senses the curve of the lens when focusing. By turning the screw, the eccentric wheel is moved a few macrometers forwards or backwards. A handy boy with a grinder can grind the screwdriver at an angle himself. Sand nicely smooth after grinding so it will not damage anything. The bevel angle is 20 or 30 degrees, it doesn't matter much. The angled face of my screwdriver is about 4mm wide. As always when working on a camera or lens, use a bifocal loupe when turning the screw so you'll see precisely what you are doing.

Erik.
 
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length is 13,5 cm

Erik.
 
Throw the rangefinder out for a minute...

When lenses (all of them!) are mounted on the camera and set to infinity does the image appear in sharp focus on the film plane? This is the first question that needs to be answered by any Technician. An advanced home repair amateur can check for collimation with an slr (with a long focal length lens) and a couple of tripods.

If the answer to the above question is yes then the next part is really rather easy, adjust the rangefinder to be perfectly aligned when (any) lens is mounted focused at infinity and pointed at the moon.

You are talking about Leica Glass on a Leica body, lens cams do not "wear out" and accepting anything else but a correctly adjusted camera lens/RF should not be an option.
 
MarcoIIIc said:
Throw the rangefinder out for a minute...

When lenses (all of them!) are mounted on the camera and set to infinity does the image appear in sharp focus on the film plane? This is the first question that needs to be answered by any Technician. An advanced home repair amateur can check for collimation with an slr (with a long focal length lens) and a couple of tripods.

If the answer to the above question is yes then the next part is really rather easy, adjust the rangefinder to be perfectly aligned when (any) lens is mounted focused at infinity and pointed at the moon.

You are talking about Leica Glass on a Leica body, lens cams do not "wear out" and accepting anything else but a correctly adjusted camera lens/RF should not be an option.
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That makes sense to me. But I feel like I'm going around in circles over this. I don't want to talk ill of Youxin, he's mostly done great work for me in the past. But when I asked him about this issue, he basically said that it was "good enough." After a few more e-mails, it didn't seem like he was interested in discussing further.

If anyone has a shop that they would recommend (not Youxin and maybe not DAG b/c he'll have the camera for ages), let me know. Alternatively, I guess I could try doing it myself.
 
TenEleven said:
There is a non destructive way to adjust the lenses, if and only if they are short of infinity on the RF which I will detail here:
Get some women's nail-color "top hard coat" or "varnish". Mine is called "topcoat" - it is clear. No color. Your wife may have it. It is clear and dries quite flat and very hard. It sticks well to brass and aluminum in my experience. Gently apply a very thin(!) it only takes very little(!) layer to the spot where the infinity position is on the lens cam, or if you want to adjust the whole range the whole cam. I've done either or depending on the lens and its focus behavior.
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I've done this using silver slide-binding tape, trimmed to size after applying, but I like this idea much better! Next stop, the cosmetics aisle...
 
Jonathan R said:
So Erik, just to be clear, are you saying that you dedicate a camera body to one particular lens by adjusting the rangefinder? And after making that adjustment that camera body may or may not suit other lenses?
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Just out of curiosity (it's been a long time since I've had any Leicas) does this mean Leica got rid of the little round plug on the bottom that allowed reaching up through a hole to access the screw with a normal (although long) screwdriver? IIRC you had to remove the loading diagram to get at it.
 
I found a method for adjusting infinity a while back. Since I do some tinkering with rangefinder cameras, some fixed lens. Using a medium telephoto lens mounted on a tripod with a known lens of accuracy at infinity you place the camera needing adjustment with its lens directly in front. Get some tape and mark the side facing the telephoto lens camera placing it across the film plane of the camera needing adjustment and adjust until the marks on the front of the tape are in sharp focus looking through the telephoto lens. It has been some time since I did this. I read some and it is possible to point the camera at a star and adjust the rangefinder until at infinity the rangefinder matches the images. I know most of those posting have professional equipment but like using a CRT to check and adjust the shutters by analyzing the images as seen through the back of the camera as the shutter operates...there are ways to fix things short of sending the camera off.
 
Just wondering, does anyone have a tool to measure the tension on the first curtain of a Contax I or Contax II so I can tell how much tension is needed when setting up the shutter after changing the ribbons? Does anyone know how much tension is needed?
 
Adjusting a camera so a lens will focus at infinity with a particular lens is an important thing to know. Something like how does a radio wave get from point a to point b, it must pass through some medium of some sort, never figured that one out.
 
MarcoIIIc said:
Throw the rangefinder out for a minute...

When lenses (all of them!) are mounted on the camera and set to infinity does the image appear in sharp focus on the film plane? This is the first question that needs to be answered by any Technician. An advanced home repair amateur can check for collimation with an slr (with a long focal length lens) and a couple of tripods.

If the answer to the above question is yes then the next part is really rather easy, adjust the rangefinder to be perfectly aligned when (any) lens is mounted focused at infinity and pointed at the moon.

You are talking about Leica Glass on a Leica body, lens cams do not "wear out" and accepting anything else but a correctly adjusted camera lens/RF should not be an option.
Click to expand...

It depends on how the lens was optimized by Leica or anyone else. The Summarit 5cm F1.5: perfectly in focus at Infinity, at minimum distance at F1.5 will be out of focus by 1"~2", will display front-focus. Stop down to F2.8, it will be in perfect focus at minimum distance and focus past infinity. The Focal Length is 51.1mm on the Five that I've taken apart. Use a lens on an M Monochrom with a deep Orange or Red filter, the focus will be off- usually towards infinity. Pick your optimization, and know how to compensate when using under different configurations.
 
Shafovaloff1 said:
Adjusting a camera so a lens will focus at infinity with a particular lens is an important thing to know. Something like how does a radio wave get from point a to point b, it must pass through some medium of some sort, never figured that one out.
Click to expand...

Electromagnetic propagation requires no medium. There is no medium. As to not knowing how that can be, you are in good company!
 
I did not know quite where to post his. Having just learned how to post a picture I thought this might be a good time though. Swapping out springs from a Kiev 2 or Contax II into a unit from a Contax 1(e), just a start, a good look. P1030342.JPG
 
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