another picture of the moon

GHGraham

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6 Mar 2010 - 10:25 PM

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Chromatic abberation can also appear as blue or green halos/lines around objects and is most obvious when two areas have a high contrast ratio between them such as the bright moon and dark sky of the cosmos.

Every lens suffers from it because different wavelengths of light (colours) refract at different angles so your lens acts like a prism, splitting the white light into its natural components including those wavelengths you cant see such as UV and IR. Each colour refracts differently so you end up seeing each colour separately on your image.

Shooting wide open makes it worse cos the light has to bend more at the edge to reach the focal point than light entering at the centre of the glass.

You can minimize it by setting the f stop to f8 - f11, avoiding high contrast scenes, retouching with software or selling your pets for medical experiments to fund expensive lenses with fancy coatings that correct specific wavelengths by having 1/2 wavelength thickness coatings deposited on them.

Nice shot by the way.

Constructive Critique!