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Proper "rule" for pinpoint stars with M43

Started Oct 27, 2016 | Discussions thread
OutsideTheMatrix
OP OutsideTheMatrix Veteran Member • Posts: 9,876
Re: Calculation from scratch; practical measurement

Thanks for the math, I found that very illuminating!

The results seem to vary depending on the pixel density of the sensor.

On the 10 MP E-520 a 15 sec exposure at 14mm viewed at 100% was perfectly fine. 20-25 sec were okay, but slightly blurred. I found 30 sec objectionable. But 15 sec on that sensor seemed pinpoint to me even viewed 1:1 on a 19" 1280x1024 display.

On the 16 MP E-PL6, the results are somewhat different. 15 sec at 14mm seems objectionable, because stars close to each other seem to get blurred into one. 13 sec is about the same. 10 sec is okay, but stars are still a bit too elongated for my taste. I found 8 sec to be just right on that sensor for 1:1 viewing on a 19" 1280x1024 display. 6 sec did not seem to be significantly better so I stuck with 8 sec at 14mm.

BTW another thing I noted is that star trails seem more objectionable with dimmer stars than the bright ones.  The bright stars seem to have some bloat that actually makes the trails less apparent at 15 sec.

 OutsideTheMatrix's gear list:OutsideTheMatrix's gear list
Nikon Coolpix P900 Olympus PEN E-PL6 Olympus OM-D E-M10 II Olympus M.Zuiko Digital 14-42mm 1:3.5-5.6 II R Olympus M.Zuiko ED 75-300mm 1:4.8-6.7 II +9 more
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