Effective focal length of Leica IIIf rangefinder

[sweat100]

I would like to ask what is the effective focal length of the rangefinder window in the IIIf? I know that the viewfinder is 50mm but I am not sure about the rangefinder. I heard is 90mm or 135mm. I am not that sure.

 

[Cactus jACK]

i think that the rangefinder / focusing window has a mag rate of x1.5... not sure what that translates into in terms of focal length...

 

[sweat100]

i think that the rangefinder / focusing window has a mag rate of x1.5... not sure what that translates into in terms of focal length...

If that is the case I take it that it is around 75mm? It may be a bit dodgy in this kind of assumption, but i guess that is a good estimate. If not, I have to test this out empirically.

 

[Srono]

Hmm, IMO, magnification doesn't help in calculating angle of view (focal length). It also depends on how *big* it is. I think about this: in other leica M, only changing frameline helps u change the FOV, while the mag rate is still fixed.

I think it is easier to look into the RF to get the FOV, try to use a zoom lens to match and read the value ;p

 

[YOL925]

Seems to be way longer than 75mm...more like 180mm ;p
(but don't take my words for it. try it out)

YOL

 

[Cactus jACK]

apologies if my previous post was misleading, the x1.5 mag focusing view is for focusing accuracy... it would still be x1.5 mag if the view is widened or narrowed (adjusting what you call the "effective focal length" of the view).

so there is really no need to consider the "cropping" of the view, but if you really must know what focal length gives a similar view (as Srono and YOL925 have suggested) best way to find out, is to put a FF (d)slr mounted with a 70-200 next to it and see at what focal length your lens reads when it has a similar view.

 

[sweat100]

Thanks all, I will have to try out what gives the most similar FOV to get a desired tele lens of it.