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What Perfect Correction for LOCA Looks Like
Secondary longitudinal chromatic aberration (secondary LOCA) causes a distracting “color bokeh” to the image, which barring creative license is always a negative. Moreover secondary color errors distort reality. Even APO lenses nearly always have secondary color errors.
Perfect correction
What does perfect correction (elmination) of secondary color errors look like?
Perfect is not an absolute term (one could probably measure a very small error with precision gear), but the Coastal 60/4 is as neutral as it gets. Moreover, the Coastal 60/4 is corrected over a very wide spectral band, exceeding even that of the Zeiss 250/5.6 SuperAchromat.
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- Eases into photographic challenges with an introductory section.
- Covers aspects of digital sensor technology that relate to getting the best image quality.
- Technique section discusses every aspect of making a sharp image handheld or on a tripod.
- Depth of field and how to bypass depth of field limitations via focus stacking.
- Optical aberrations: what they are, what they look like, and what to do about them.
- MTF, field curvature, focus shift: insight into the limitations of lab tests and why imaging performance is far more complex than it appears.
- Optical aberrations: what they are, what they look like, and what to do about them.
- How to test a lens for a “bad sample”.
Intrigued? See Focusing Zeiss DSLR Lenses For Peak Performance, PART ONE: The Challenges, or (one topic of many) field curvature.
