Archived posting to the Leica Users Group, 1998/04/29

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Subject: Re: [Leica] Pictures taken with SOOKY-M
From: Chris Bitmead <chrisb@ans.com.au>
Date: Thu, 30 Apr 1998 06:10:27 +0000

Eric Welch wrote:

> But in this case, you are no optical expert, and they are. I named one
> highly respected one whom I have talked to about this. Arthur Kramer, who
> has forgotten more about photography than most here will ever know (and
> that's no slam on them!)

Yeah. Pity we're not discussing photography, but rather biology.

But if you put so much stock in what a photographer say, let me
quote form "The New 35mm Handbook" by Michael Freeman.

"Perception. The complete coverage of the human eye is
approximately 240 degrees, although this varies from person to
person. However, with the eye in a fixed position, most of the
view is fuzzy and ill-defined, with only a tiny spot covering
less than 2 degrees beng completely sharp. Away from this central
point of focus, the resolution deteriorates.

Now where does 46 degrees come into it?

> Whom are we to believe? Just because you post it on the internet? Just
> because it's so
> easy for you to say it isn't so without backing it up? Does it start to
> sound like a Monty Python skit?

Ok, I'll back it up with an experiment anyone can perform.

1) Hold out both hands to your sides. Wiggle your fingers and
look straight ahead. Most folks can see them wiggling. Therefore
the angle of view of the eye is at least 180 degrees.

2) While reading this mail message, concentrate on one word only.
Don't move your eyes from that word. You will find you can't
really read more than one or so words on either side of the word
you are looking at. Therefore the highest perception is only a
few degrees of view.

Now you show me what experiment to do that shows me that there is
something special about 46 degrees.

> Well, magnification is the same regardless of whether it's an eye, or a
> lens, or whatever.

How so? The magnification with a camera depends on how you view
the resulting picture. The magnification will be different
depending on whether you view a slide, a slide with a 8x loupe, a
6x4" print, a 8x10" print, a 20x24" print and it also depends on
how close you view the print. So how are you going to compare the
magnification of the eye to that of a camera?????????????

> Not it isn't.
> 
> Ah, proof positive! I'm convinced. Now I'll buy that parrotflex.

I would have thought you were old enough to know what your eyes
can perceive. You don't need two doctorates and a professorship
to figure this out.

- -- 
Chris Bitmead
http://www.ans.com.au/~chrisb
mailto:chrisb@ans.com.au