Color Correction (LOCA, Secondary LOCA, LACA)
Perhaps two or three lenses lenses on the market have perfect color correction, at the cost of a quite slow maximum aperture. One fast f/1.4 lens has strictly controlled color aberrations, soon to be joined by a sibling.
For a very well corrected lens, longitudinal chromatic aberration is often the limiting aberration at full aperture (e.g., Zeiss 100/2 Makro-Planar), and even with “APO” lenses (loosey-goosey term) there is often a lingering bit of that (LOCA), and a great deal of secondary longitudinal chromatic aberration (secondary LOCA). By definition (mine), a well-corrected lens has absolutely minimal lateral chromatic aberration and also strictly controls LOCA and SLOCA, e.g. the class-by-itself Zeiss Otus 55mm f/1.4 APO-Distagon.
Making Sharp Images is going to see major additions this year, and I’ve started by adding various new material on color aberrations. Material will be steadily added in the coming months in all areas.