On Wed, 26 Jan 2000, Glen Lowry wrote:
> Doris went Zuikhotic & pontificated thusly:
>
> > I do not find a huge difference between the 24/2.8s
> >SC & MC versions in sharpness, though there is in flare control. As it
> >happens, I like the little extra flare of the SC. As to the flatness,
> >the light where I photograph most often (you could call it "N-1 country")
> >is usually very contrasty, so that's an asset, not a liability.
>
> I'm a little confused by this statement about using lenses to
> control contrast. I was under the impression that the contrast
> of the materials is entirely different from lens contrast, and
> that in fact a contrasty lens as long as it also has good
> resolving power will better render shadow detail. Am I missing something?
> [snip]
I don't know about missing anything, Glen. Our Father, Ansel Adams,
has the following to say on this:
" Several years ago a motion-picture photographer was perplexed
because when he used an optical-flat neutral density filter to reduce
exposure he obtained a higher shadow value in relation to highlight
value than when he reduced exposure by simply using a smaller aperture.
Paul Strand found he obtained a smoother negative with his Cooke lens
than with his Dagor. Neither person could explain the reason for this
effect, nor could I; at that time there was scant mention of the subject
in photographic literature. " <minor snip>
" The increased flare from the extra reflecting surfaces actually added
density to the negative (apparent in the shadow areas and other low-value
areas), "smoothing out" the contrast difference between high-value and
the shadow areas."
(from Book 4, under _Qualities of Natural Light_, Shade/Diffused
General Light)
On this same topic, Our Father Ansel also says...
[remember, he's talking about uncoated lenses]
" In simple lenses the flare effect is immaterial. But as the number
of air-to-glass surfaces increases, the cumulative effect of the
internal reflections is to reduce image contrast seriously.
Flare therefore has a definite effect on the quality of the images
produced by any uncoated lens. The difference between the theoretical
contrast and the contrast actually obtained is called the flare factor,
it can be expressed as a ratio
Bs
------
Bi
The brightness range of the subject divided by the brightness range
of the image."
He goes on a little further down...
" Actually, flare can sometimes be used advantageously ".
and...
" Hence irrespective of the contrasts within the lower values,
the image from the coated lens will always be more brilliant --- that
is, have a greater contrast range --- than the image from an uncoated
lens. It will be obvious that with an uncoated lens we may obtain
" false " opacities for the lowedt image values --- mistaking opacity
from flare as opacity from actual exposure. With a coated lens used with
the same subject and same exposure these low values would appear
quite underexposed "
****************** (highlights by La Fang)
(The above is from Book 2, _The Negative_, under Lens flare and image
contrast.)
Father Ansel seems to be in agreement what I was saying above
regarding the reduction of contrast in the image (he goes on to give
actual values, etc., too much to reproduce here) by adding opacity
in the low-value areas due to the pre-flash effect of flare.
If most of your contrast problems are of the "too-little" kind
(and if so, believe me, you ARE blessed)
(or live in a fog bank)
then yes, by all means you want a hotshot, zero-flare optic.
But my contrast problems tend to run in the other direction (way too
much and too often), so the slight flare of the magnificent Zuiko SC's
is a proven, decided and visually apparent advantage. Specially when
using contrastier transparency films. I know it's
terribly distressing to embrace an "imperfection" like flare for
a lot of numb-er loving technophiliacs on here, but it can work for you.
Remember, the right tool for the job...:-)
*= Doris Fang =*
[Tired from typing the above and hunting through her too-old
Adams books to find the stuff]
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