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From: briand@tekig1.UUCP (Brian Diehm)
Newsgroups: net.rec.photo
Subject: Re: lens for view cameras
Message-ID: <1850@tekig1.UUCP>
Date: Wed, 27-Feb-85 17:02:52 EST
Article-I.D.: tekig1.1850
Posted: Wed Feb 27 17:02:52 1985
Date-Received: Mon, 4-Mar-85 05:41:25 EST
References: <163@rtech.ARPA>
Distribution: net
Organization: Tektronix, Beaverton OR
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> 	I have a question on view camera lens. I read somewhere that
> large format lenses are not as sharp as those for, say, 35mm cameras. Is
> this true? If so, is it a physics problem, or is just that more people
> buy 35mm cameras than view cameras?
> 
> 	As long as I'm asking, does anyone know of a negative densitometer
> (for black and white) that doesn't cost an arm and a leg? Or perhaps where 
> I could get a set of negatives of known densities? I'd like to be able to 
> figure out the development times for various film, developer, and push/pull 
> combinations.

Well, yes, view camera lenses probably are less sharp than 35mm lenses, but it
probably isn't anything to do with the market.  The difference is the tremendous
coverage that a view camera lens must have.  Compare a "telephoto" 35mm lens of
210mm with a slightly long view camera 210mm.  Both lenses produce the same size
of image - something that is 3mm tall with one lens is 3mm tall with the other.
But.  The 35mm lens must cover an area 24x36mm, while the 210 must cover 4 x 5
inches.  Not only that, but the 35mm lens is guaranteed to use the axis centered
image area while the view lens may be used severely off axis.  For this reason,
my primary view lens (210mm Schneider Symmar S) will cover an 8 x 10 inch area
clear out to the edges.

This explains why a 210 lens is "telephoto" on a 35mm camera while being modest
long on a view camera - the 35mm image is using only a "part" of the available
image area, if you want to think of it that way.

The implication that a 35mm image is inherently sharper than a view camera is
wrong - the "enlarged" image area MORE than compensates for the coverage
requirements of the lenses.  Also, the grain reduction of large format comes
into play.  I personally have found that the grain factor outweighs ALL other
sharpness factors.  One of my view lenses is a 135 Zeiss Tessar, the original
triplet design that led to all triplets being known as "Tessar type."  This
lens was out of production in the 1930s (if that late), and I'll put it up
against any 135 on a 35mm, provided you make a large (8x10 or larger) print of
the full image on the negative.

The reason I think marketing doesn't have much to do with this area is that
(this may come as a surprise to Pop Photo readers) large format is a HUGE
market.  Lens research continues, the Japanese have entered this area within
the last five years in a BIG way, and a typical commercial lens alone will
cost, and dearly.  A 120mm Super Angulon (f8), about equivalent on a 4x5 to
a 35mm on 35mm format, will cost you about $700-800 at discount.  Typical top
of the line Sinar view cameras will go to studios for $2000 to $3000.  The
neat thing is that you and I can get much less pretentious gear for pretty
reasonable prices - the Calumet 540 is a real bargain at $250.  However, you
also need a lens :-) ! (My 210 Symmar is under $400 these days.)

Last question - consider using one of the 1-degree spot meters as a densi-
tometer.  The secret is, each 1/3 f-stop deflection on the meter is equal to
0.1 transmission density.  Read a light source without the negative, then
read it with the negative - presto.  Ansel Adams covers this in the second
book of the New Basic Photo Series (1983?), but you have to look for it.

Brian Diehm (who apologizes for the previous messed up posting)