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    Re: Digital Image CN Exercise
    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.
    In a message dated 4/6/2010 1:10:30 A.M. Bangladesh Standard Time, gregrudzinski@yahoo.com writes:


    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'


    10 mega pixel (Canon EOS XTi)
    200mm fixed lens
    1/4000s shutter speed
    ISO 100
    Circular polarizers
    Mono chromatic black and white

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