bosjohn
Member
Most of you already know all this but for those new it might prove useful.
Understanding your M leica range finder and how it works will go a long way in using it effectively in varied situations.
the rangefinder measures the distance by triangulation with the so called base length at the camera as one side of the triangle and the light path to each view finder and range finder window the other two sides.
effective base length is the combination of actual distance between the two prisms or mirrors i.e. the windows and the magnification of the view finder or range finder if separate.
The longer the effective base length the more accurate the range finder. Some modern range finders use lasers for even more accuracy but if I were you I wouldn't be holding my breath waiting for them to appear in cameras.
The M leica was for many years unique in that it is both a coincident and split image rangefinder. When the patents ran out Mamaya used the design in their Mamaya six and since then it has shown up in Cosina and Konica cameras.
The venerable Erwin Puts had a quite lengthy article on range finder accuracy which has been removed from his site but the gist of it is that split image range finder is a factor of ten times more accurate than split image, Leitz figures 25% more being they are conservative and German. In any event if you have any straight lines in your image use the split image method for the greatest accuracy, To do this use the top or bottom edge of the rangefinder patch to line up the lines. no vertical lines? don't be lazy turn the camera.
Range finder use does take practice to minimizing hunting that is going back and forth to find focus. When I shoot street I am almost always shooting at f 5.6 or so so I just run the focus till it looks coincident and stop no hunting allowed.
As most of you are aware the M cameras for years suffered from attrition of various light baffles in the range finder to make room for meters and to lessing the cost of manufacture. By the time you get to the M six there are some serious flair out situations of the range finder unless your very careful to center your eye and if need be shade the finder with your hat or anything else that work.
frame lines are notoriously inaccurate so in fast street shooting just aim and pray by the time you have made a nice framing of the scene its often gone.
Not using the range finder is one of the more important range finder methods of work. the down and dirty set the f stop to infinity marking on the lens barrel and note the index indicating how close you can shoot to be within the depth of field as determined by the Leitz engineers.
A note about depth of field. Depth of field is not an exact science one persons tolerance for softness will not be the same as another. Almost all depth of field information we use today was calculated back in film days when the assumption was you would be viewing something eight by ten or smaller. You may want to revise your working habits for depth of field and narrow the range a tad to be more in keeping with the forty inch monitor at pixel level.
Understanding your M leica range finder and how it works will go a long way in using it effectively in varied situations.
the rangefinder measures the distance by triangulation with the so called base length at the camera as one side of the triangle and the light path to each view finder and range finder window the other two sides.
effective base length is the combination of actual distance between the two prisms or mirrors i.e. the windows and the magnification of the view finder or range finder if separate.
The longer the effective base length the more accurate the range finder. Some modern range finders use lasers for even more accuracy but if I were you I wouldn't be holding my breath waiting for them to appear in cameras.
The M leica was for many years unique in that it is both a coincident and split image rangefinder. When the patents ran out Mamaya used the design in their Mamaya six and since then it has shown up in Cosina and Konica cameras.
The venerable Erwin Puts had a quite lengthy article on range finder accuracy which has been removed from his site but the gist of it is that split image range finder is a factor of ten times more accurate than split image, Leitz figures 25% more being they are conservative and German. In any event if you have any straight lines in your image use the split image method for the greatest accuracy, To do this use the top or bottom edge of the rangefinder patch to line up the lines. no vertical lines? don't be lazy turn the camera.
Range finder use does take practice to minimizing hunting that is going back and forth to find focus. When I shoot street I am almost always shooting at f 5.6 or so so I just run the focus till it looks coincident and stop no hunting allowed.
As most of you are aware the M cameras for years suffered from attrition of various light baffles in the range finder to make room for meters and to lessing the cost of manufacture. By the time you get to the M six there are some serious flair out situations of the range finder unless your very careful to center your eye and if need be shade the finder with your hat or anything else that work.
frame lines are notoriously inaccurate so in fast street shooting just aim and pray by the time you have made a nice framing of the scene its often gone.
Not using the range finder is one of the more important range finder methods of work. the down and dirty set the f stop to infinity marking on the lens barrel and note the index indicating how close you can shoot to be within the depth of field as determined by the Leitz engineers.
A note about depth of field. Depth of field is not an exact science one persons tolerance for softness will not be the same as another. Almost all depth of field information we use today was calculated back in film days when the assumption was you would be viewing something eight by ten or smaller. You may want to revise your working habits for depth of field and narrow the range a tad to be more in keeping with the forty inch monitor at pixel level.
archive59
Established
You may want to read this thread:-
http://www.rangefinderforum.com/forums/showthread.php?t=92283
Mark
http://www.rangefinderforum.com/forums/showthread.php?t=92283
Mark
bosjohn
Member
interesting but all my life in range finder cameras the efective base length based on the physical distance betweenthe pisms and the magnification of the finder have been the standard with which range finders are compaired. whether in actual fact a longer physical base is better than a shorter one with magnification is more or less moot cus what we get is a combination anyway.
My choice for the most accurate range finder on a thirtyfive mm camera has got to be the Kodak bantam special with an eight power scope for the range finder.
My choice for the most accurate range finder on a thirtyfive mm camera has got to be the Kodak bantam special with an eight power scope for the range finder.