Originally Posted by Trondster
I guess my point was that those terms are all used interchangeably - but that doesn't mean that such use is correct. There are lots of people who say or write the word, 'irregardless,' but that doesn't make it a word, nor does the common use of the word 'data' as a singular noun (e.g., the data is correct) make that usage correct - data are plural (except when used as the proper name of a Star Trek character, of course.
The distinction becomes important in other types of lens applications, for example in confocal microscopy where out-of-focus light is eliminated by a pinhole in the optical path, but axial CA can still be present if the lens is not sufficiently corrected. That's why the lenses on my confocals are fluorite or planar apochromatic lenses corrected for SA and CA in at least 3 and usually 4 colors - (and many of them cost well into the 5-figure range).
The thing I have trouble reconciling is that despite the purple fringing, the chart looks focused and sharp. Other Nikon fast primes (50/1.4, 85/1.4, 85/1.8) exhibit similar fringing - not just the 135/2. So there are a few possibilities:
- Bryan is intentionally trying to make these lenses look bad.
- Bryan is not very good at focusing on his test chart.
- There is some unidentified step in the testing workflow that is introducing an artifact into the results.
- The fringing is a 'feature' of some Nikon lenses.
I don't buy the first two at all. The third one is certainly possible. The fourth one is also possible - bear in mind that pure black on pure white illuminated by four SB-900 or 580EX II strobes generates more contrast than most 'real-world' shots.
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