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Old 21-03-2021, 12:41 AM
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Astrofriend (Lars)
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Join Date: Aug 2017
Location: Stockholm, Sweden
Posts: 334
Today I anlyzed my flats that I have taken with my Pentax 645 300 mm lens, they are takne at full aperture, f/4. As I expected the vignetting is very low, much lpwer compare to my Canon 300 mm L lens. That was one of the goals. Of course I want it to be a sharp lens too. It looks okay but at one corner the stars are a bit elongated, it must come partly because of a tilt of the camera house. The bayonette adapter doesn't fit very well and cause this.

This how the vignetting looks:
http://www.astrofriend.eu/astronomy/...ignetting.html

/Lars
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