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Carl Zeiss ZF.2 18mm f/3.5 Distagon T*

Sagittal Coma Flare

See the actual pixels crops in the Night lights example for the 28/2 Distagon.

Discussing the 18/3.5 behavior relative to the 28/2 Distagon sagittal flare. sagittal flare ties into bokeh and other aspects of lens performance.

DIGLLOYD: Can we expect to see any strange "shapes" for point sources near the edges/corners of the frame wide open with the 18/3.5 Distagon as is seen with the 28/2 Distagon?

Zeiss: 'Bird wings' are of course much less visible with the 18/3.5 as compared to the 2/28 due to the more moderate speed. This is already indicated by the MTF-curves: 'bird wings' mean sagittal flare, and this is expressed in a considerable drop of low frequency MTF towards the corners. This is not the case with the ZF18.

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ZF 18/3.5 @ f/3.5 and f/5.6
15mm offset (just outside corner of DX frame)

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