[pure-silver] Re: {Spam?} Re: Repurposing Enlargers
- From: Tim Daneliuk <tundra@xxxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Mon, 12 Dec 2011 22:28:01 -0600
On 12/12/2011 10:19 PM, Richard Knoppow wrote:
----- Original Message ----- From: "Jean-David Beyer" <jeandavid8@xxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Monday, December 12, 2011 5:51 PM
Subject: [pure-silver] Re: Repurposing Enlargers
Gerald Koch wrote:
I still hold with the conventional idea that enlerging lenses do no make
good camera lenses. This also works the other way around; camera lenses
do not make good enlarging lenses.
Jerry
That may have been true before WW-II, but I doubt it is true anymore.
And as some users of dialyte enlarging lenses would say, they work
pretty well as camera lenses too. Artars have considerable use as camera
lenses. And many of these are pre WW-II.
FWIW, the Apochromatic Artar is a symmetrical lens which has
its best correction for unity magnification. They work very
well as enlarging lenses for large format where the
magnification is not great. These lenses hold their corrections
well with variation in distance; for process or enlarging work
the range is about 1:4 to 4:1. At infinity there is a loss of
correction for coma which can be compensated by stopping
down. If stopped down about two stops the correction is
excellent out to infinity. Note that some later Artars, such as
the Red-Dot series, were adjusted (probably by element spacing)
to optimise them for other than 1:1. The catalogue data
indicates the lenses supplied in shutters were optimised for
greater distance than those supplied in barrels, the latter
almost always used for process work. In general, the variation
in correction with distance is a function of speed and the
coverage angle, that is, fast lenses, and wide-angle lenses,
tend to loose corrections faster when used at a distance other
than designed for. So, an f/4.5 Tessar camera lens works pretty
well for enlarging but an f/2 lens off a 35mm camera is likely
to leave something to be desired.
My experience with both the 14" RD f/9 and the 19" APO f/11 Artars
is that they are consistently tack sharp from the front of the lens
to infinity on my Wisner Technical field. Then again, I never shoot
them anywhere near wide open. This experience is repeated across
many different kinds of subjects and light conditions. While I have
no doubt that my other lenses (150mm f/5.6 APO Symmar,
72mm Super Angulon XL, and 210 mm f/6.8 Caltar II) are all more
properly corrected as taking lenses, in a practical shooting environment
the Artars work just fine.
As an aside, while I love the Schneiders, that Caltar II (a rebranded
Rodenstock I think) is just SCARY sharp and a real delight to shoot
with. The 72mm SA XL gets lots of looks when on the camera. When
I was in Zion National Park shooting some years ago, one of my
companions asked to look at the ground glass. I had the top
of a 300 foot cliff and the sand in front of my feet in frame at
the time. He looked at me and said ... "You need to step back or
your toes will be in the picture...."
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