Camera out of adjustment with lens by .0003 experts help?

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68degrees

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This seems like a question for the optics forum. Im wondering about this article in Modern Photography posted here.
http://www.rangefinderforum.com/forums/showpost.php?p=788661&postcount=5

In the first part of that article you will see them talking about a Kodak Signet 35. They tested two units and one of them was off by only .0003 and the other I assume was off by much more. They say it the camera was out of adjustment with the lens and that a competent shop can adjust it but what I want to know is what exactly is out of adjutment, how can I tell if mine is out of adjustment and if it is out of adjustment how can I put mine back into adjustment without sending it to some exotic expensive lab someplace. We are rangefinder men we must stick together. Thanks.
 
Is yours showing a focus error?

3 ten thousands of an inch is incredibly precise. I doubt most repair shops can get anything that close.
 
digitalintrigue said:
Is yours showing a focus error?

3 ten thousands of an inch is incredibly precise. I doubt most repair shops can get anything that close.
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I dont know if my camera is out of adjustment at all but in the article it said that they were shooting identical new cameras kodak signet 35s and on the brick wall test, one of them failed miserably. They were both tested for camera to lens adjustment whatever that is and the good camera was only out by .0003 and the other camera was way out of adjustment and had to be sent to a "competent shop" for adjustment.

I never heard of this before and just want to know what adjustment they are talking about, how can I tell if mine is out of adjustment and how to get it back into adjustment.
 
digitalintrigue said:
If you haven't noticed any focus issues already, you have nothing to worry about. :)
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Ive only shot one roll through it and thought it was pretty good but maybe it could be a lot better. Id like to do a test and actually measure it and dial it in like they did. What adjustment are they talking about anyway?
 
I have no idea what dimension they are talking about, but . . . it does not say that the dimension MUST be within .0003" of spec, it simply says that the good camera was extremely close to dimensional spec.
The bad camera for all we know was .100" out of spec :D

As stated above, if you can't see a problem, stop worrying about it.
 
Most home shops are not set up for such fine tolerances. I have held .0002 once but that was fitting two parts, not having to measure them. Long ago I took several Nikon F's into the inspection department of the machine shop I worked in. They used their coordinate measuring machine to check from the film rails to the lens flange. The oldest was uniform all around to the limit of their machine which at that time, 1975, was one ten thousandths or .0001 of an inch. The other F was out by several tenths but in many years of shooting I never noticed any difference between the two.

If you were shooting a Noctilux, wide open, on a digital M, that level of precision might matter. On any other camera and lens, I don't think you would notice. Joe

Holding .0002 was at home. Once I worked a group of hones and held ten millionths routinely but that was with specialized measuring equipment. One of the most difficult questions in machining is how accurate do you need to be.
 
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68degrees, they are probably talking about lens to film distance, that is, whether the lens is focusing properly on the film plane vs. in front of or behind the film plane.

Actually measuring this in practice, and concluding that it's off by .0003" is difficult. Verifying that you have good focus or best focus is easier. Do you know how to test your focus accuracy?
 
take 3 shots, one in perfect focus. Then move .0003" closer, then back. Develop and examine the prints.
 
If one is assuming we are dealing with a camera body that is made of aluminum,then,because aluminum expands considerably more than this with the application of body heat alone,it would lead to constantly changing focus the longer you hold the camera. Ludicrous;no?
 
Wait, you mean you are talking about an article from a magazine that was published almost 60 years ago? And that you can't see a fault with your camera? Is this just some game you like to play, posting inane and misleading questions just to entertain yourself? Well, I for one refuse to play it.

PF
 
farlymac said:
Wait, you mean you are talking about an article from a magazine that was published almost 60 years ago? And that you can't see a fault with your camera? Is this just some game you like to play, posting inane and misleading questions just to entertain yourself? Well, I for one refuse to play it.

PF
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Did you read the article that I posted? If you did then you will see this is legit question and not a game. Its irrelevant how old the article is as the camera is also 60 years old. I want to know what adjustment they are talking about. Is it simply a discrepancy between what the focus ring says and how in focus the image actually is? Simply bring the image into focus with a ground glass across the film plane and then adjust the focus scale ring accordingly? Is that what this is about or is there some other adjustment?
 
68degrees said:
They say it the camera was out of adjustment with the lens and that a competent shop can adjust it but what I want to know is what exactly is out of adjutment, how can I tell if mine is out of adjustment and if it is out of adjustment how can I put mine back into adjustment without sending it to some exotic expensive lab someplace.
Click to expand...

There are two potential adjustments they could be talking about, but given the tolerances, I'm going to go with lens adjustment. How they get .0003" from such an inexact camera is beyond me but whatever.

You can check the lens focus accuracy at home with a small piece of ground glass and a loupe. As others have pointed out above, if you're getting sharp negatives and the depth of field is "in the right place" (ie, where you focused, not in front of or behind), you don't need to do this.

Anyway, set your camera up on a sturdy tripod, open the back and tape the ground glass to the focal plane. Open the lens up (B or T) and focus on an object 2 feet away. Do the same for infinity. Are both sharp when you look at the image with your loupe? If not, you'll want to adjust the lens focus. You'll find excellent instructions on how to do that here.

The page above also gives instruction on setting up the rangefinder focus.

I think once you've seen how it's done (and how much "slop" there can be in the camera), you'll see that .0003" is a pretty astounding accuracy to aim for.
 
kievreport said:
There are two potential adjustments they could be talking about, but given the tolerances, I'm going to go with lens adjustment. How they get .0003" from such an inexact camera is beyond me but whatever.

You can check the lens focus accuracy at home with a small piece of ground glass and a loupe. As others have pointed out above, if you're getting sharp negatives and the depth of field is "in the right place" (ie, where you focused, not in front of or behind), you don't need to do this.

Anyway, set your camera up on a sturdy tripod, open the back and tape the ground glass to the focal plane. Open the lens up (B or T) and focus on an object 2 feet away. Do the same for infinity. Are both sharp when you look at the image with your loupe? If not, you'll want to adjust the lens focus. You'll find excellent instructions on how to do that here.

The page above also gives instruction on setting up the rangefinder focus.

I think once you've seen how it's done (and how much "slop" there can be in the camera), you'll see that .0003" is a pretty astounding accuracy to aim for.
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Thats great thanks for the link. That makes the most sense and is easiest. Im curious though what was the other adjustment that you thought it could be? You mentioned two potential adjustments.
 
If we are talking of film cameras, where the photo film thickness is around 0.16mm and the sensitive layers take the first 0.09mm; ¿what mean a precision of 0.0076mm? Than will have perfect focus in the blue sensitive layer and not in the others? Or perfect focus in the yelow filter layer and out of focus in all the sensitive layers?

In my adapters, 0.1mm is the difference between Contax Rangefinder and Nikon S, bad focus at less of f5.6.

For "perfect focus" at f1:1.5 or f1:1.4 the tolerances on my adapters are +/-0.02mm "using my test lenses"

Any lens marked 50mm really can be 48mm to 52mm in the best cases:
http://www.zeisscamera.com/articles_focallength.shtml
So add to all the variables this other and forget adjusts of 0.0003"
 
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68degrees said:
Ive only shot one roll through it and thought it was pretty good but maybe it could be a lot better. What adjustment are they talking about anyway?
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If you don't even know what they're talking about then you shouldn't worry.

Also I'm sure you could be a lot better as well. Any focus error you may notice is more likely to be because of you swaying back and forth than the camera.
 
swoop said:
If you don't even know what they're talking about then you shouldn't worry.

Also I'm sure you could be a lot better as well. Any focus error you may notice is more likely to be because of you swaying back and forth than the camera.
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So in other words you don't know the answer.
 
Why don't you take the camera apart and find out where the .0003" discrepancy lies?
As was stated before, this is a measurement that is thinner than the emulsion itself. Your heartbeat will make your body move more than this. Your pupil dilating due to changes in light will slightly change your point of focus in your eye.
This is not anything to be worried about but if you think it is, go ahead and start filing away or building up the mount with solder then filing it away.
If you can make good photos with it right now, you shouldn't worry about it because if you got .0003" closer there is no possible way you would be able to tell the difference.

Phil Forrest
 
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