NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Digital Image CN Exercise
From: Jeremy C
Date: 2010 Apr 13, 19:53 EDT
From: Jeremy C
Date: 2010 Apr 13, 19:53 EDT
Interesting methods Greg. You will have to forgive me for not
attempting you problem as my very slow internet connection doesn't allow me to
easily download images.
Have you considered the diffraction issues by shooting at f22? I am
not up on Canon optics, but I would suspect that diffraction might cause some
fuzziness in the sun's limb. I wonder if a x4 or x8 ND filter added
to the mix would get the lens to f8 or f11 to eliminate this problem for the
most part. Of course another added filter in the stack might also cause
some other issues so it might be an even trade off or worse off.
Jeremy
In a message dated 4/6/2010 1:10:30 A.M. Bangladesh Standard Time,
gregrudzinski@yahoo.com writes:
Marcel,
Attached is a high altitude 200mm lens calibration photo of the Sun.
Date 19 March 2010 UTC 19:39:37
Lat 34° 10' N Lon 119° 14' W
Hc 54° 58.7'
Semi Diameter 16.06'
Full Diameter 32.12'
Measured pixels 332
Minutes per pixel .09675'Settings:
10 mega pixel (Canon EOS XTi)
200mm fixed lens
1/4000s shutter speed
ISO 100
f22
Circular polarizers
Mono chromatic black and white
GRudzinski
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