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Lateral Chromatic Aberration

Lateral Chromatic Aberration and Astigmatism

When astigmatism does not improve by stopping down, or when it actually worsens, the cause is sometimes lateral chromatic aberration.

Lateral color has a major impact on MTF curves. With several charts at different apertures one can usually differentiate astigmatism and lateral color.

The off-axis tangential MTF curve stays more or less constant as the lens is stopped down, e.g., from f/2.8 to f/8, while the sagittal curve improves. This is a a clear sign that lateral color is involved.

If both tangential and sagittal curves improve at about the same rate when the lens is stopped down, then there is a good chance that the lens has little lateral color. Of course, various optical aberrations can commingle, confusing the issue.

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  • Depth of field and how to bypass depth of field limitations via focus stacking.
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  • Optical aberrations: what they are, what they look like, and what to do about them.
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Intrigued? See Focusing Zeiss DSLR Lenses For Peak Performance, PART ONE: The Challenges, or (one topic of many) field curvature.

Aperture series 2.8, 5.6 available in full article
MTF for Zeiss 25mm f/2.8 Distagon

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