I hesitate to go any further, because I have such respect for your
judgment and the care that you use in your photography.
There is no question that there is variability in the warmth or
coolness of lens rendition. I agree. A lot of it is the taste of the
manufacturer and people used to be advised to buy the camera maker's
lenses if you want uniformity in color rendition if you planned switch
lenses in the middle of a shoot. A good manufacturer who makes their
own lenses will attempt to make the color rendition uniform. It is
probably done by absorption of spectral bands that emphasize opposite
parts of the spectra. I remember reading articles in Leica Fotographie
discussing the color effect of the cements gluing some of the lens
elements together. Then different kinds of glass, number of elements
and coatings each have their effects. In those instances certain
portions of the spectrum are being absorbed so that other parts appear
to be enhanced. It seems to me though that no part of the spectral
saturation is increased, just the opposite parts are decreased and our
brain sees the warmth or coolness. If a rose is the equivalent of a
photoshop 256 red the lens cannot make it 300 red. The best you can
hope for is that your will transmit close to 256 and that it will do
an equally accurate transmission of the other colors. If it does not,
then it could look too red even even if it only transmits 225 red. It
is a question of spectrum balance in the image made up of less light
than that which hit the front surface of the lens, not that it has
somehow increased the saturation of red from the front to the back of
the lens.
I would question whether lens contrast was consciously adjusted down
in the past because of film, that is to match them. I think lenses
were made as well as they could be seen to function considering the
level of print material available. When film materials improved and
larger prints became fashionable so that the lens flaws could be
seen, then lens development proceeded. But I could be wrong and you
could be correct. Or we are saying the same thing in different ways.
Winsor
Long Beach, California, USA
On / March 9, 2008 CE, at 5:51 PM, C.H.Ling wrote:
>
> Many poeple think high contrast is good or as you say a lens close to
> perfect design should have high contrast. I have different guess
> here, in
> the film age, lens has to design to match the contrast of film. Or
> back to
> the very old age when multicoating was not very propular, film was
> designed with higher contrast and later both have to fix contrast to a
> certain range.
>
> Even the very cheap lens can have very high contrast, like the Sigma
> 70-300
> APO UC I once own (Minolta AF mount), the contrast is very high from
> 70-200,
> the images were very un-nautral. The non all MC 35 shift has the
> natural
> color that I like, the 90/2 has higher color saturation and good for
> flowers. Too many coating can cause color shift, if you control the
> coating
> better like Zeiss the color will be more natural, if not, like some
> Pent*a
> SMC and Tamron BBAR coating, the color tone could be shifted or at
> least
> different from the others.
>
> At the mean time I think it is well known that even within Zuiko
> some are
> having warmer tone than the other. And in my experience most of the
> later
> Zuiko AF for OM707 have very cool tone.
>
> C.H.Ling
==============================================
List usage info: http://www.zuikoholic.com
List nannies: olympusadmin@xxxxxxxxxx
==============================================
|