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RichS · Posted: Thu Nov 17, 2005 6:05 am Post subject:

Okay, I know this has been asked. I did search and just couldn't find the answer. What's worse is that I knew the answer, so chaulk it up to a lost brain cell. Make fun of me or yell at me and point me to an old message, but here's the dumb question...

I was checking the focus of my Super yesterday with a long lens (210mm) against the cam installed. Worked fine until I got down to 3.5 feet. It was only then that I realized that there was a big enough distance between the lens and film plane to make a big difference in measuring the distance for the rangefinder. It was also about then that I realized that I had forgotten which one to use...

So, when you do the rangefinder distance, is it to the lens or film plane?

And be gentle. I may be too tired now to care but tomorrow is another day

Thanks...

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"Ya just can't have too many GVIIs"

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45PSS · Posted: Thu Nov 17, 2005 8:38 am Post subject:

[ This Message was edited by: 45PSS on 2005-12-24 21:03 ]

RichS · Posted: Fri Nov 18, 2005 6:04 am Post subject:

What I was trying to do was check a home made cam for accurate rangefinder use. Meaning the distance needle on the top.

Of course I focused using the GG, then checked the RF, then the needle. It was just confusing at that moment because I couldn't remember if the measurement from the subject, at 3.5 feet, was to the lens or the film plane and the 12 or so inches of lens extension would make quite a difference in linear measurement.

Although I still can not find a printed reference stating what to measure to, there was a much simpler solution.

I just put the 135mm and cam back in and checked that focus at 3.5 feet... Duh...

Thanks...

glennfromwy · Joined: 29 Nov 2001 Posts: 903 Location: S.W. Wyoming

I don't know about the top rangefinder but the Kalart instructions state that measurements for adjusting are to be taken from subject to rangefinder. Square on, as it will be off if the subject and camera are at an angle to each other. That means in all directions.I hope this gives you some ideas.

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Glenn

"Wyoming - Where everybody is somebody else's weirdo"

RichS · Posted: Mon Nov 21, 2005 4:49 am Post subject:

Glenn,

Yes, I read that. I believe they are talking about parallax correction and having the target square with the rangefinder and then square with the lens. They don't mention the actual position of measurement though. That's what I was talking about. At the short range of 3.5 to 4 feet, it can make quite a bit of difference if you measure from the target to the lens, rangefinder or filmplane...