lagrassa Posted July 21, 2009 Share #1 Posted July 21, 2009 Advertisement (gone after registration) I have a Leica IIIc with a 5cm lens but have not taken any photos with it yet. I understand that the lens focusing ring while using the rangefinder is correct for the 5cm lenses. I also understand that there are external shoe-mount viewfinders for other focal length lenses to show you a frame correct for the lens focal length. My question is how does the focusing of a lens that is not 5cm get represented in the rangefinder? Is the rangefinder only useful for the 5cm lenses? Sorry for my not understnading how this all works. Link to post Share on other sites More sharing options...
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Michael Hiles Posted July 21, 2009 Share #2 Posted July 21, 2009 The rangefinder window to the left of the viewfinder works for all lenses of all focal lengths up to 135mm. Just mount the lens and focus. The camera's view finder - the right window - is for the 50mm lens only. If you use the external viewfinder for another focal length, you focus in the standard way, then look through your external viewfinder and press the button to make a masterpiece. Link to post Share on other sites More sharing options...
lagrassa Posted July 21, 2009 Author Share #3 Posted July 21, 2009 Thank you. That explains it perfectly. Link to post Share on other sites More sharing options...
earleygallery Posted July 21, 2009 Share #4 Posted July 21, 2009 Indeed it's as Michael has said. I use a 25mm Skopar on my lllf, its not rangefinder coupled and has 3 zone focus click stops which make it really quick to use for street shooting. Lovely little lens and great on an LTM camera. Link to post Share on other sites More sharing options...
lagrassa Posted July 21, 2009 Author Share #5 Posted July 21, 2009 So the rangefinder is coupled for lens focal lengths 50-135mm but not for lens focal length of 35mm? Link to post Share on other sites More sharing options...
ismon Posted July 21, 2009 Share #6 Posted July 21, 2009 The rangefinder is coupled to any lens that you put on the body. They interface via the rangefinder in the body riding on a threaded cam at the rear of each lens. Most lenses have that cam, unless they are Very old (like for a collector). Because you can't see through the lens to take a photo, you need an appropriate Viewfinder to show you what that lens "sees". Since a 50mm is considered a "normal" lens, that viewfinder is built into the camera. Other lenses require other viewfinders, to be mounted in the shoe atop the camera. A popular viewfinder for your IIIc is generally known as an IMARECT. It is adjustable, outlining the fields for lenses from 35 to 135mm. Link to post Share on other sites More sharing options...
doubice Posted July 21, 2009 Share #7 Posted July 21, 2009 Advertisement (gone after registration) So the rangefinder is coupled for lens focal lengths 50-135mm but not for lens focal length of 35mm? All screwmount 21mm to 135mm lenses made by Leica (except ones made for the Visoflex reflex housing and some very early ones from the early 1930's) are / were coupled to the rangefinder. Only some recent Leica Thread Mount lenses made by Voigtländer/Cosina are not coupled - i.e. 15mm Heliar, 25mm Skopar etc. The reason for this was probably reduced cost and the theory that such wide lenses, with their immense depth of field, could be 'guess-focused'. This theory has been disproved by Sean Reid - any lens, no matter what its depth of field is, will produce sharper images when correctly focused. That may be why all the latest Voigtländer/Cosina lenses are being introduced with RF coupling. Best, Jan Link to post Share on other sites More sharing options...
Michael Hiles Posted July 21, 2009 Share #8 Posted July 21, 2009 This theory has been disproved by Sean Reid - any lens, no matter what its depth of field is, will produce sharper images when correctly focused. Absolutely. There is only one plane of focus. Focused is focused, unfocused is less sharp. The rest is bivone fertilizer. Link to post Share on other sites More sharing options...
lagrassa Posted July 21, 2009 Author Share #9 Posted July 21, 2009 Thanks all for the information. Now I understand completely. Link to post Share on other sites More sharing options...
jc_braconi Posted July 22, 2009 Share #10 Posted July 22, 2009 lagrassa please check your personnal message box, Link to post Share on other sites More sharing options...
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