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Proper "rule" for pinpoint stars with M43

Started Oct 27, 2016 | Discussions thread
Giiba
Giiba Regular Member • Posts: 414
Re: Calculation from scratch; practical measurement

boxerman wrote:

OutsideTheMatrix wrote:

I just noticed something really curious. 13 seconds is acceptable if you're talking about stars near the center of the field. But when those same stars drift towards the edge of the field, the star trails appear to blend close stars together. I wonder if stars trailing more near the edge of the field could be caused by lens distortion or perhaps a lower resolution near the edge of the lens?

That sounds right to me. I have read that lens coma, which gives you elongated images for points, is especially critical for astrophotography. So, that's a thing to look for. I don't think it's just lack of resolution, but maybe that contributes, too.

Lack of coma distortions is one of the key things to look for in a lens for shooting stars. Some lenses smear points across 20 or more pixels just from this imperfection. The only place I know of that tests this is Lenstip reviews.

 Giiba's gear list:Giiba's gear list
Olympus E-M1 Olympus 40-150mm F2.8 Pro Panasonic Leica DG Summilux 15mm F1.7 ASPH Olympus 8mm F1.8 Fisheye Pro Panasonic 8-18mm F2.8-4 +1 more
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