The animation is fun to watch and illustrative. From f/16 you see the diffraction kicking in (if I am correct).
Yeah, that\'s right. The aperture blades get in the way, cause too much disruption, and the disrupted waves start distorting and canceling what would otherwise be a clean image waves.
Actually I\'m somewhat surprised at the (maybe exaggerated) softness even past f/8. The f/16 and f/22 stops I rarely use on any lens ... I have not yet had a lens which produces good images at those settings.
I don\'t see any in the F8 sample. I can barely notice a tad at f/16 - but hat\'s easily recovered in PP. At f/22 it\'s pretty bad tho. I have a few lenses where it\'s pristine from f/2 al the way through to f/32 or f/22. So it\'s not impossible. If I recall, this Tessar was designed in the 50\'s even tho they were still manufactured up until recently (or maybe even still are ?). 70\'s and later designs are typically better.
Keep in mind that the anim is composed of unprocessed 100% crops tho. Nada... from RAW straight to dithered 256 color GIF frames. So according to HIS mathematics this means you have to sit 1.5 meters from the screen in order to not notice any of the low color dithering at typical LCD dot pitches.
Here\'s what the entire frame looks like processed and scaled to 16%:
My M42 Tessar can be pretty sharp at f/2.8 - I think it\'s more related to focussingdistance than anything else. I think I\'ve read in the ZF/ZE/ZM thread (or any of the other Zeiss related threads) that indeed lensperformance may be quite different between close-up or at infinity.
Yeah, I\'ve read such things as well. It\'s probably true. I can\'t remember ever trying to test it tho. It makes sense - the way internal focus groups work. So I don\'t doubt it.
The animation is fun to watch and illustrative. From f/16 you see the diffraction kicking in (if I am correct).
Yeah, that\'s right. The aperture blades get in the way, cause too much disruption, and the disrupted waves start distorting and canceling what would otherwise be a clean image waves.
Actually I\'m somewhat surprised at the (maybe exaggerated) softness even past f/8. The f/16 and f/22 stops I rarely use on any lens ... I have not yet had a lens which produces good images at those settings.
I don\'t see any in the F8 sample. I can barely notice a tad at f/16 - but hat\'s easily recovered in PP. At f/22 it\'s pretty bad tho. I have a few lenses where it\'s pristine from f/2 al the way through to f/32 or f/22. So it\'s not impossible. If I recall, this Tessar was designed in the 50\'s even tho they were still manufactured up until recently (or maybe even still are ?). 70\'s and later designs are typically better.
Keep in mind that the anim is composed of unprocessed 100% crops tho. Nada... from RAW straight to dithered 256 color GIF frames. So according to HIS mathematics this means you have to sit 1.5 meters from the screen in order to not notice any of the low color dithering at typical LCD dot pitches.
My M42 Tessar can be pretty sharp at f/2.8 - I think it\'s more related to focussingdistance than anything else. I think I\'ve read in the ZF/ZE/ZM thread (or any of the other Zeiss related threads) that indeed lensperformance may be quite different between close-up or at infinity.
Yeah, I\'ve read such things as well. It\'s probably true. I can\'t remember ever trying to test it tho. It makes sense - the way internal focus groups work. So I don\'t doubt it.
Jul 13, 2010 at 07:37 AM
Previous versions of Bifurcator's message #8653646 « C/Y Zeiss Image Post »
I have a few lenses where it\'s pristine from f/2 al the way through to f/32 or f/22. So it\'s not impossible. If I recall, this Tessar was designed in the 50\'s even tho they were still manufactured up until recently (or maybe even still are ?). 70\'s and later designs are typically better.