lamiaceae wrote:
I use older vintage "film" lenses often. They seem to have far more contrast and color saturation than most modern "digital" lens. And with out the uneven sky CPLs usually give!
Yes, Graduated ND filters can be useful for landscapes, but for controlling high dynamic range, between sky, background, and foreground.
Yep. It matters whether one is using a prime with 7 elements in 5 groups (= 10 glass-air surfaces) or a zoom with
24 elements in 10 groups (= 20 surfaces).
You can get the same effect on a prime lens by screwing five filters to the front (don't worry, they're multi-coated!)
Only that's not as bad, because in a lens the group, he objective, is usually thick and always convex--perfect for
creating flare.
All that glass not only absorbs light (making the lens slower than its marked f/stop) and may create visible flare,
but it also creates insidious flare that reduces contrast. The image looks fine except the contrast has been reduced.
MTF charts for lenses use slow spacial frequencies within the field of view (black and white bands) as a measure
of contrast. But the worst flare is caused by bright lights (such as the sun)
outside the field of view. So
MTF charts don't measure flare.
Because zooms are very susceptable to flare, one should always use a lens hood that matches the angle-of-view.
Unfortunately, the angle-of-view changes with the focal setting of a zoom.
Zooms before the 1980 were designed by hand, so they had a lot of aberrations and distortation. But all zoom
designs are a compromise, so all zooms have more aberrations and distoration (at least at certain focal settings)
and an equivalent prime.
The better corrected a zoom is, the more elements it has, so the more light it absorbs and the more flare it
creates. Manufactures try to reduce the flare with coatings, but no coating is perfect, and none will help
when a bright light from outside the angle-of-view strickes the objective of the lens.
Zooms are convenience lenses or for situations where there is no time to change lenses. (The are also good
for very high contrast scenes, as a way to reduce contrast. I carry one for this very purpose.)
Also, if you go way back, some prime lenses were less corrected, and so had more aberrations and distortion,
but fewer elements and groups, and therefore less absorption and flare.
There is no perfect lens. You pay your money and you take your choice, as the saying goes.
But if you pay a lot for a zoom lens, you are paying to get the least-bad bad lens, not the best lens.