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

[Mark Rabiner]

A normal lens as we define it today by what the diagonal of the format or
darned close to it is also has other considerations.
A lens around 43mm with a 43mm image circle is the easiest lens to design
and manufacture.  Its also usually the sharpest.  And its the cheapest.
That's called "getting your cake and eating it too". Normally you get one of
the other. You get your cake. But you don get to eat it.
You want better paying less money is not the way to do it. Yet here it is.
Normally in a lens line the sharpest lens with the best all around imaging
characteristics, acutance, contrast whatever is going to be a normal.
They'll tell you the sharpest is their famous short tele but its BS. They
just think you have to spend a large amount to get something superior.
A 50mm or close for a Leica or Nikon
An 80mm or 75mm for a Rolleiflex or Hasselblad
A 160mm for 4x5.

For a 1.5 crop sensor its a 28mm lens.

For an 8x10 its 325mm.  12.8 inches.








On 9/18/16 2:31 PM, "Mark Rabiner" <mark at rabinergroup.com> wrote:

> They eye is way wider than 43 degrees. Way
> The eye sees as much as 90° and gets into 100°.
>> 
https://en.wikipedia.org/wiki/Peripheral_vision#/media/File:Field_of_view.svg>>
<
> 
> So your eye is a 14mm or 12mm lens.
> But the part its paying way more attention to is a built in 135mm that's the
> paracentral and central area according to this diagram.
> So we have two two two lenses in one built into the way we see.
> At least.
> Though most of it is bokeh.
> But its like the dated and in jeopardy traditional Leica viewfinder
> Its a framelines which you can look way beyond the edges of.
> A framelines for the lowly but my favorite 135mm focal length.
> 
> So determining what is Normal for the way a human sees is pretty close to
> impossible. They have to get a number from somewhere. So they picked the
> diagonal of the format.
> 
> On 9/17/16 9:22 PM, "Dennis Kushner" <dennis.leicam6 at gmail.com> wrote:
> 
>> I agree with Osterloh. I have always considered the following statement
>> I
read 
>> somewhere over
40 years ago. The view angle of the lens closest to the
>> average 
>> 43 degree
angle of the human eye.


On Sat, Sep 17, 2016 at 5:13 PM, Steve
>> Barbour <steve.barbour at gmail.com>
wrote:

>
> > On Sep 17, 2016, at 1:36 PM,
>> Peter Dzwig <pdzwig at summaventures.com>
> wrote:
> >
> > I am using the 35mm
>> f2 
>> Fuji on the XE-2 and X-Pro 1 which is about 45.5
> > equivalent (taking 1.3
>> as 
>> the equivalence ratio). I was "sold" the 35 as
> a "sort
> > of equivalent"
>> to 
>> a 50mm f2. It works great too.
> >
> > Still wish I could find an adaptor (to
>> M) for my f1.4 50mm MC-Rokkor, a
> truly
> > wonderful lens, if bulky.
>
>
>> looks available, sent separately.
>
> steve
>
>
> >
> > Peter
> >
> > On
>> 17/09/2016 16:47, Nathan Wajsman wrote:
> >> It sure is. And very sharp too.
>> It has become my most-used lens. If I
> go out with the Fuji and just one
>> lens, this is the one.
> >>
> >> Cheers,
> >> Nathan
> >>
> >> Nathan
>> Wajsman
> >> Alicante, Spain
> >> http://www.frozenlight.eu
>> <http://www.frozenlight.eu/>
> >> http://
> snip




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