Toothwalker wrote:
For the Y/C 2.8/21 there is a third version, in the book "Only Zeiss".
I tried to buy that book last year, but couldn't find it at a price I was willing to pay.
Toothwalker wrote:
The Zeiss focus criterion is to optimize the MTF at 20 lp/mm, in the image center at full aperture.
There is no refocus for measurements at reduced apertures.
Good information.
wayne seltzer wrote:
No, I am talking about different global contrast levels of lenses so that shadows are rendered darker than you may want and hightlights brighter than you want too.
And:
wayne seltzer wrote:
The 24G renders the various light levels in the scene more like what I saw, where as the 25/2 seems to brighten the highlights more and darken the shadows more.
This suggests the Zeiss has greater flare resistance, which wouldn't surprise me in the least. While better flare resistance can in theory make the highlights brighter, I doubt the tiny difference would be visible there; rather, any differences would be visible in the shadows, where even a small amount of non-image-forming light can dramatically brighten things.
My own Zeiss lenses have noticeably better flare resistance, in general, than my other lenses. I think this difference is caused by coatings more than anything else, though possibly some types of glass/polymer used for lens elements have non-negligible internal scattering. Maybe Zeiss pays more attention to the effect of element shapes on ghosting.
Veiling flare and ghosting can add mystery, drama, or straightforward visual interest to a photo, so they're not always bad. But flare also reduces colour saturation and colour accuracy, since it pollutes strong colours like blues skies with non-imaging-forming light (which is often dirty white).