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Tom
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, May 12, 2004 - 07:50 pm: | 
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Learned to use second camera as collimator and have it down pat. Several of my cameras were off at infinity. My question is this, if I get infinity focus correct, does that mean that with my rangefinders, all that would be left to do would be to adjust rangefinder at infinity and several shorter distances, say 10 feet and 30 feet for instance. |
David Nebenzahl
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, May 12, 2004 - 10:20 pm: |
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Yes. Actually, if your rangefinders don't have interchangeable lenses, then you only should have to adjust the rangefinders on them at infinity; they will then be correctly adjusted for all distances.
So far as I know, you only need to adjust for both infinity and closer distances when there's a cam or some other part in the linkage that can be adjusted differently for close distances than for far ones (for example, the cam on the end of the rangefinder actuator arm on a screw-mount Leica). On a fixed-lens rangefinder, the linkage should be fixed, so you only need to do the one adjustment. |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 13, 2004 - 05:25 am: |
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Also the lenses which are permanently mounted on rangefinder cameras suffer from tolerances, and to be precise, each rangefinder should be calibrated to match the actual focal length of a lens. However, most camera manufacturers neglect this point. Thus it may happen that a rangefinder which is dead on oo is slightly off at closer distances. I found a few rangefinder mechanisms which allow for compensating the close distance error as well.
I once made a calculation for a 75mm lens on a 6x6 camera and found that 1% in focal length variation will cause an error of approx. 10cm when the rangefinder indicates 1.5m. At longer distances the error will become much smaller.
German standards allow tolerances of 0.5% of focal length. |
Sam Styles
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 13, 2004 - 07:57 am: |
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Im hopeing to set the focus on a Zeiss Ikon Nettar tonight, does the same apply to that? i.e. will I only have to set the focus for infinity and the rest should fall in to place? And could you tell me exactly where infinity is? 
I was just going to set an object at exactly 5 meters away and set the focus on that. Would that be ok to do, rather than try and focus on infinity which seems a bit inaccurate to me.
Sam
http://www.sjsphotos.co.uk |
Ed
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 13, 2004 - 11:20 am: |
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If your lens is sharp at infinity then I would adjust it at, say, 15 feet. This is on at all distances. You don't critical rf focus at infinity. If you want infinity, I would say 1/2 mile or more away. More is better than less. |
Tom
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 13, 2004 - 02:38 pm: |
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I had to see it to believe it, but it is true. I just focused 2 Auto S 2's and 1 Lynx 14E to infinity using another camera as a collimator, and each one was dead on at closer distances. So I am happy with just infinity focus. Thanks to everyone for the help. |
