I want to use a Bahtinov mask to focus stars with a Panasonic Leica DG Elmarit 200mm f2.8 MFT.

So far I found out that the geometry of the perfect Bahtinov mask changes significantly with the lens parameters. What is the ideal Bahtinov mask pattern for my lens?


1 Answer 1


I don't know how to calculate the ideal Bahtinov mask for a particular lens, but in my experience, the filter-style Bahtinov masks (etched polycarbonate plastic, very dense line pattern) work much better for photographic lenses than the laser-cut lower-density line patterns that are typically used over telescope objectives.

Generally, for camera lenses, think "filter" instead of mask. Those from Kase, LonelySpeck, and the like, are great for photographic lens purposes. E.g.: Kase 100mm × 100mm Night focus tool (Bahtinov); Kase Wolverine circular Bahtinov 77mm; LonelySpeck Sharp Star 2.

For telescope optics, use the appropriate "mask" (occluding) style Bahtinov.


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