04-27-2021, 09:32 PM
04-28-2021, 02:01 AM
Klaus, you usually comment on MTF charts. Don't they suggest uncorrected enough of coma?
Given their 85mm 1.4 DN I was expecting something lighter.
Given their 85mm 1.4 DN I was expecting something lighter.
04-28-2021, 05:31 AM
(04-28-2021, 02:01 AM)borisbg Wrote: [ -> ]Klaus, you usually comment on MTF charts. Don't they suggest uncorrected enough of coma?
No?
04-28-2021, 10:28 PM
The delta between the solid and dotted curves at 30 lp/mm is fairly marginal so astigmatism is quite low.
Astigmatism = whether the rays of the sagittal plane are focused at a different point than light rays in the tangential plane. If the curves don't match, you will see a line instead of a point (center to corner direction)
Coma = rays don't focus in a point on the plane resulting in a comet-like form.
I haven't thought about coma too much so far but the corner MTFs are high so I'd conclude that the coma is low.
Astigmatism = whether the rays of the sagittal plane are focused at a different point than light rays in the tangential plane. If the curves don't match, you will see a line instead of a point (center to corner direction)
Coma = rays don't focus in a point on the plane resulting in a comet-like form.
I haven't thought about coma too much so far but the corner MTFs are high so I'd conclude that the coma is low.