Archived posting to the Leica Users Group, 2001/06/01

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Subject: Re: [Leica] Bokeh - OT Long
From: Ron Schwarz <rs@clubvb.com>
Date: Fri, 01 Jun 2001 16:40:14 -0400
References: <DBBA6A949168D411B6B800508BDFB895C71C1D@USWSTNT422>

My (possibly faulty) understanding has been that the "camera obscura" was a
darkened room with one wall holding the image formed by a pinhole "lens" in
the opposite wall.

If so, then the "clue" is mistaken, because there's no such thing as "out
of focus" with a pinhole "lens".  A pinhole -- in addition to having
complete absence of distortion and flare, and perfect color correction --
has infinite "depth of field".  When the distance between the objective
(the pinhole) and the focal plane changes, focal *length* changes.  IOW, it
becomes a zoom lens.  But focus remains infinite.

Of course if he used an actual lens in his C/O then the clue remains valid.


At 10:25 AM 6/1/01 -0700, you wrote:
>>Mystery of Vermeer's technique uncovered...
>
>
>I for one will be very interested to see the book - I am a big fan of
>Vermeer's work and over the years have amassed a small library of titles
>related to "the Master of Delft."
>
>His use of a camera obscura has been debated for years, and while many
>scholars believe Vermeer did use one to make his pictures (the tell-tale
>blurs [particularly visible in "The Lace Maker" and "Girl with a Red Hat"]
>and unusual perspectives being the usual "clues" given), many others
>disagree.
>
>Whatever the case may be, there has never been any concrete proof that he
>used one. I'm not sure if such a thing can be proved - mathematically or
>otherwise - but it is sure to keep many a tongue-wagging and generate a few
>more books that - fool that I am - I run out and buy.
>
>Guy
>
>

Replies: Reply from Guy Bennett <gbennett@lainet.com> (RE: [Leica] Bokeh - OT Long)
Reply from Guy Bennett <gbennett@lainet.com> (RE: [Leica] Bokeh - OT Long)
In reply to: Message from "Gil, Miguel (US - Los Angeles)" <mgil@deloitte.com> ([Leica] Bokeh - OT Long)