[Klaus]

https://www.sigma-global.com/en/lenses/a021_35_14/

E- & L-mount as usual.

[borisbg]

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.

[Brightcolours]

Klaus, you usually comment on MTF charts. Don't they suggest uncorrected enough of coma?

No?

[Klaus]

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.