Archived posting to the Leica Users Group, 2008/05/10

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Subject: [Leica] Leica R-10 at Photokina 2008
From: jhnichols at (Jim Nichols)
Date: Sat May 10 10:03:04 2008
References: <><00f601c8b133$ca9f11d0$6101a8c0@jimnichols> <>


In my first consideration of this issue, I did not think about the corners. 
When you think it through, it is ALL about the corners.  I stand corrected.

Jim Nichols
Tullahoma, TN USA
----- Original Message ----- 
From: "Jeff Moore" <>
To: "Leica Users Group" <>
Sent: Saturday, May 10, 2008 11:22 AM
Subject: Re: [Leica] Leica R-10 at Photokina 2008

> 2008-05-08-13:48:57 Jim Nichols:
>> I agree with Gene.  If a lens will cover 36mm in width, it will cover the
>> same dimension in height. Hence, it should cover at least 36x36mm.
> Er, what part of the Pythagorean theorem is confusing here?  Don't just
> count on words which sound nice together; draw the two formats packed
> into circles, with the enclosing circles just kissing the corners of the
> enclosed rectangle (which might be a square).  If an image circle is to
> be guaranteed to cover a rectangular format, the circle's diameter must
> be greater than or equal to the format's diagonal. The format's diagonal
> is the square root of the squares of the sides.
> For 24x36mm, that's 43.3mm (hence the Leica MTF graphs which go from
> zero to 21.6mm, half that -- the radius from center to edge of the image
> circle which covers 24x36).
> For 36x36mm that's 50.9mm.
> 50.9 is bigger than 43.3.
> Sure, some current R lenses (especially the longer ones) may have
> coverage to spare, but more coverage *would* be required.
> -Jeff
> _______________________________________________
> Leica Users Group.
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In reply to: Message from grduprey at ( ([Leica] Leica R-10 at Photokina 2008)
Message from jhnichols at (Jim Nichols) ([Leica] Leica R-10 at Photokina 2008)
Message from jbm at (Jeff Moore) ([Leica] Leica R-10 at Photokina 2008)