«

On Wed, 15 Dec 2010 00:27:36 +0100, Alfred Molon
<> wrote:

>Why is a 50mm lens "normal" (in a full frame camera)? Because it
>corresponds to the usual angle of view of the human eye, or just because
>this focal length lies in the middle between wide and tele?

I think you will find that it's acceptance stems from the original
f3.5 Elmar lens fitted to the early Leica. The lens telescoped into
the camera body and could be no longer than the thickness of the body.
When extended the length of the lens plus the thickness of the body
came to 50mm.



Eric Stevens

In article <>,
Eric Stevens <> wrote:

> On Wed, 15 Dec 2010 00:27:36 +0100, Alfred Molon
> <> wrote:
>
> >Why is a 50mm lens "normal" (in a full frame camera)? Because it
> >corresponds to the usual angle of view of the human eye, or just because
> >this focal length lies in the middle between wide and tele?
>
> I think you will find that it's acceptance stems from the original
> f3.5 Elmar lens fitted to the early Leica. The lens telescoped into
> the camera body and could be no longer than the thickness of the body.
> When extended the length of the lens plus the thickness of the body
> came to 50mm.
>
>
>
> Eric Stevens

Yes, but they chose a 50mm for a reason. As Savageduck points to in the
wiki, the angle of view of a 50mm lens on a 24mm x 36mm negative is very
similar to the angle of view of the human eye. Anything from 40mm to
60mm can be considered normal for 35mm. In general the diagonal of the
imaged area on film is approximately "normal", with room for
interpretation.

Oskar Barnak's original prototype of 1923, the Leica 0, had a
collapsible Anastigmat 50mm f/3.5 which was permanently mounted on the
camera body. Interchangeable lenses were introduced in 1930

The Leica was originally designed as a pocket camera. All early
non-telephoto Leica lenses were either pancake or collapsible. Starting
in 1925 the Elmar 50 f/3.5 and in 1931 the Hektor 50 f/2.5 were
collapsible. In 1933 the Summar 50 f/2.0 collapsible wasn't a big hit as
a high-speed lens. In 1939 the Summitar 50 f/2.0 was released which, in
1945, was the first Leica lens with an anti-reflection coating and had
lanthanum glass elements. The outer appearance stayed the same
(collapsible) in 1951.

35mm and 28mm Leica lenses were pancakes and didn't need to be
collapsible. The Elmar 35mm f/3.5 was introduced in 1930, along with the
50mm; the Hektor 28 f/6.3 in 1935. The early telephotos starting with
the Hektor 75 f/1.9 in 1931 were true telephotos and in rigid mounts.

With the introduction of the "M" series bayonet-mount lenses Leica
discontinued new designs in collapsible mounts. They did put the
original screw-mount Elmar 50 f/3.5 into a bayonet mount for the
introduction of the M3 in 1954, followed by the Elmar 50 f/2.8 in 1957
(and a new version in 1994 to go with the 40th anniversary M6 special
edition). Briefly there was a collapsible version of the Summicron 50
f/2.0 which was replaced in 1956 with a rigid mount.

"shiva das" <> wrote in message
news:shiv-...
> In article <>,
> Eric Stevens <> wrote:
>> On Wed, 15 Dec 2010 00:27:36 +0100, Alfred Molon
>> <> wrote:

>> >Why is a 50mm lens "normal" (in a full frame camera)? Because it
>> >corresponds to the usual angle of view of the human eye, or just because
>> >this focal length lies in the middle between wide and tele?
>>
>> I think you will find that it's acceptance stems from the original
>> f3.5 Elmar lens fitted to the early Leica. The lens telescoped into
>> the camera body and could be no longer than the thickness of the body.
>> When extended the length of the lens plus the thickness of the body
>> came to 50mm.
>>
>> Eric Stevens

> Yes, but they chose a 50mm for a reason. As Savageduck points to in the
> wiki, the angle of view of a 50mm lens on a 24mm x 36mm negative is very
> similar to the angle of view of the human eye. Anything from 40mm to
> 60mm can be considered normal for 35mm.

Ummmm!!! I've heard and read this "hokum" too many times
to count, but as I've tried to point out in several articles on sight
and photographic imaging on my web site, the "mechanics" of
photographic imaging and seeing have almost nothing to do with
each other in too many instances to come to the simple conclusion
above. In this particular instance, the angle of view of human sight
may be specified as anything from about 220 degrees to a tiny
fraction of one degree!

> In general the diagonal of the
> imaged area on film is approximately "normal", with room for
> interpretation.

This is an acceptable (and accepted) photographic standard that
has very little to do with human sight...
--David Ruether
www.donferrario.com/ruether
d_ruether....@....hotmail.com