I will add that chromatic abberation is even less likely in this case
since you were using a mirror lens. Mirrors (by themselves) have zero
chromatic abberation. A catadioptric instrument such as the Maksutov or
Schmidt Cassegrain designs each adds a refracting element in the front
in order to correct the coma and/or spherical abberation of the primary
mirror. The refracting corrector element is a potential source of
chromatic abberation but the amount tends to be rather small. In this
case the Schmidt design is superior to the Maksutov since the corrector
plate is very thin and near flat and introduces a negligable amount of
chromatic abberation.
Chuck Norcutt
Moose wrote:
> Scott Peden wrote:
>> I have pics of a shelf of cameras 25-30 feet away that I took with that
>> Celestron, the color variation was interesting though, each shot was just a
>> little different. That is Chromatic aberration?
>>
> No
> <http://www.dpreview.com/learn/?/Glossary/Optical/chromatic_aberration_01.htm>.
>
> More likely auto color balance with slightly different views of colored
> things and/or mixed lighting. Try one of the fixed color settings. That
> will give you color consistency in such a situation.
>
> Auto color balance only really works on subjects that have all colors in
> them in relative balance. With mono-colored subjects, it works very
> badly. Although this example is with auto color in software, you will
> get a similar effect with it in a camera
> <http://www.moosemystic.net/Gallery/tech/Scan/GreenDoor/9-641_25wb.htm>.
>
> I know you said RAW is not on your agenda yet, but this is another
> reason to shoot RAW, especially in mixed lighting. With JPEG, the camera
> does its color balance thing, and that's what you get. Although it is
> often possible to recover in post, sometimes some colors have been lost.
> With a RAW file, no color balance has been applied, That is done in the
> RAW conversion process, under your control.
>
> Other solutions to accurate color are targets that you shoot under the
> subject lighting which act as reference points in RAW conversion and/or
> post. My favorite it the WhiBal
> <http://www.rawworkflow.com/products/whibal/index.html>.
>
> Moose
>
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