[Leica] How did 50mm become the "normal" lens for 35mm cameras?

[Mark Rabiner]

My first SLR lens  in the early 70's was the Nikon 45mm 2.8 GN which I still
have. It was my only lens for many years on my just out F2.  Cosina updated
it as was it was no longer being made and it became a dozen years ago the
45mm 2.8 P Nikkor lens.  It first came out in Silver and is a manual focus
lens. I got that lens and used it extensively though needed to stop down a
couple or could not be assured of nailing the focus with the non ground
glasses on DSLR cameras so it was in effect for me a 5.6 lens for me which
has its limits even with 6400 iso's. But it was a pancake and a camera could
be slipped into a coat pocket which is as much of the basic Leica concept as
you can get.

What we call half frame now 72 on a roll 24x18mm  was first called single
frame as its movie film and that's the format very close to films being shot
then and later. The idea of doubling the frame for stills to 24x36 was very
much basic part of the Leica concept the numbers they had crunched depended
on it.. Other early 35mm film camera before Leica had a mask which was
removable so you could go between the two formats. But the smaller format
was not going to make it for  Oskar Barnack and Max Berek. There was no
removable mask it was double frame or nothing. 24x36mm
The lens on the  UR- Leica Prototype found in the museum is the  Leitz 42mm
f/4.5 Milar. A variety of focal lengths in the 40 to 60mm range were
considered from what I can make out before the 50mm focal length started it
all.

As time wore on double frame started being called single frame for the
stills guys but I had some slide mounts I bought in the 1970's which said
double frame on them . Wess I think.  From a very old camera store on
Manchester street in Maplewood Missouri with wall to wall walnut cabinets
and dark lighting.


Adam!  by the way some motion picture films were shot in the 24x36 DF format
with the film going through the camera horizontally instead of up  and down.




On 9/16/16 5:45 PM, "Adam Bridge" <abridge683 at fastmail.com> wrote:

> Let me back up a moment.

I was taught that a ³normal² lens is one whose focal
> length matches the diagonal of the film/sensor frame.

For 35mm film as shot
> by, say, a Leica M6, that turns out to be 43mm - midway between a wide 35mm
> lens and a 50mm lens which I have sometimes seen called a ³short telephoto²
> perhaps even by B&H.

Now as I remember from my cinema days 35mm movies are
> shot at the same aspect ratio as still but have different dimensions since
> they are shot with the long edge running across the film instead of the short
> edge as is the case for full frame 35mm film photography (except, I¹m
> guessing, half-frame 35mm but now I¹m totally out of school having never seen
> one of these cameras.

That¹s where I¹m coming from. And wondering why we
> don¹t see more 40-something focal length lenses. I know that there 48¹s out
> there? Nikon maybe from the old days? Mark Rabiner, you talked about this at
> some point, I 
> think.

Thanks

Adam


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-- 
Mark William Rabiner
Photographer
http://gallery.leica-users.org/v/lugalrabs/