Opticallimits

Full Version: Sigma 35mm f/1.4 DG DN ART announced
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
https://www.sigma-global.com/en/lenses/a021_35_14/

E- & L-mount as usual.
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.
(04-28-2021, 02:01 AM)borisbg Wrote: [ -> ]Klaus, you usually comment on MTF charts. Don't they suggest uncorrected enough of coma?

No?
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.