Re: [Leica] DR Summicron MTF (was: For your information)

["Ted Bayer" <tedbayer@charter.net>]

Seth Rosner wrote:

"Who has time for this stuff anyway?"

Hi Seth:

So true.

As you know, I have the 50 DR and this is very interesting stuff for me.
But it made me think of what Ted has written when others have been engaged
in long discussions about which lens is best or better than another, what
camera meter sensitivity is better, etc.  He advises we just get out and use
our cameras and lenses - that way we may learn how to take a decent picture.
And isn't that what it's all about?

I think Albert Einstein had it right, too.  He said something like this:

We learn from experience.  All else is knowledge.

Best,

The other Ted in Olalla


- ----- Original Message ----- 
From: "Seth Rosner" <sethrosner@direcway.com>
To: <leica-users@mejac.palo-alto.ca.us>
Sent: Friday, January 09, 2004 10:53 AM
Subject: Re: [Leica] DR Summicron MTF (was: For your information)


> To amplify what I wrote a little while ago:
>
> > Also remember that "sharpness" is not a objective, quantifiable value as
> are
> > contrast and resolution.
>
> Contrast is objective and scientifically quantifiable. As to resolution,
one
> has to qualify. Unlike contrast, the resolution of a lens does not
establish
> itself scientifically and mechanically and then transfer to a computer for
> print-out. Whether a resolution value is obtained by photographing a wall
> chart of smaller and smaller lines or by peering through the ocular of the
> EROS machine at smaller and smaller lines projected through the lens
(which
> is what we did at Optikos), the determined value depends upon what the
> observing human eye sees - or thinks it sees - when looking through a
loupe
> at the negative or at the projected image through the EROS ocular. What
one
> sees is to a certain extent subjective because the acuity of the human eye
> differs from one human to the next. And subjectively, if one wants to
think
> that one can see line separation at a particular set of line fineness that
> equals 250 lp/mm, perhaps one's brain will say: yes I see the separate
> lines. Erwin has pointed this out. I did not see it so clearly until this
> experience looking through the ocular at Optikos. Which is why, when we
were
> determining resolution, Roy Youman and I each wrote down our observations
at
> each f/stop before we knew what the other had "seen." And we then took the
> lower resolution value.
>
> Who has time for this stuff anyway?
>
> Seth           LaK 9
>
> --
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>


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