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Longitudinal and Secondary Longitudinal Chromatic Aberration
This page evaluates longitudinal chromatic aberration (LOCA) and secondary longitudinal chromatic aberration (SLOCA), two bugaboos of image clarity.
Lenses lacking adequate correction for these two forms of secondary color deliver images with violet haloes on backlit subjects (see this comparison) and also deliver a magenta cast to the out of focus foreground and a green cast to the out of focus background, both highly undesirable.
Example #1: Bishop Creek
This image was deliberately shot with the background out of focus. The lighting was extremely blue mountain shade at dusk, which provokes the violet haloes of LOCA in lenses that do not adequately correct for secondary color.
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Diglloyd Guide to Mirrorless offers comprehensive integrated coverage of most APS-C and full frame mirrorless cameras and lenses.
Special emphasis is placed on Sony full-frame, including Sony lenses and the high performance Zeiss Batis and Zeiss Loxia lenses plus Rokinon/Samyang and others. Fujifilm X, Olympus and Panasonic M4/3, Sigma dp Merrill and dp/sd Quattro are also covered in depth. Years in the making, it offers a wealth of material for choosing and using a mirrorless camera.
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Sony A7R III + Zeiss Batis 40mm f/2 CF
ENV: Bishop Creek, altitude 8600 ft / 2621 m, 38°F / 3°C
RAW: LACA corrected
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