Guys (Edward, Bif), I think you need to re-read the paper \"How to Read MTF Curves\" by
Hubert Nasse.
edwardkaraa wrote:
Micro-contrast and sharpness are synonymous in my opinion. When a lens has high micro contrast, it means that it is a sharp lens. Micro-contrast corresponds roughly to the 10 lpmm and 20 lpmm on Zeiss MTF tables. A high number indicates that the lens gives a very good illusion of sharpness while the 40 lpmm indicates the resolving power of very fine details.
This isn\'t quite right. Resolution just means that two image elements (line-pairs being the most simple ones) have sufficient contrast to be distinguishable from each other. Because we\'re talking about small image elements, we\'re always talking about micro-contrast and not global contrast. See the bottom half of page 16 of the Zeiss paper.
You are redefining the term micro-contrast to correlate it to 10 and 20 lp/mm but that depends on the sensor size, viewing size and distance so it\'s kind of arbitrary. You couldn\'t use those same numbers for MFT or large format lenses for example. The vertical scale on the Zeiss MTF charts simply shows the microcontrast at different resolutions (10/20/40 lp/mm) across the image\'s diagonal.
Guys (Edward, Bif), I think you need to re-read the paper \"How to Read MTF Curves\" by
Hubert Nasse.
edwardkaraa wrote:
Micro-contrast and sharpness are synonymous in my opinion. When a lens has high micro contrast, it means that it is a sharp lens. Micro-contrast corresponds roughly to the 10 lpmm and 20 lpmm on Zeiss MTF tables. A high number indicates that the lens gives a very good illusion of sharpness while the 40 lpmm indicates the resolving power of very fine details.
This isn\'t quite right. Resolution just means that two image elements (line-pairs being the most simple ones) have sufficient contrast to be distinguishable from each other. Because we\'re talking about small image elements, we\'re always talking about micro-contrast and not global contrast. See the bottom half of page 16 of the Zeiss paper.
You are redefining the term micro-contrast to correlate it to 10 and 20 lp/mm but that depends on the sensor size, viewing size and distance so it\'s kind of arbitrary. You couldn\'t use those same numbers for MFT or large format lenses for example. The vertical scale on the Zeiss MTF charts simply shows the microcontrast at different resolutions (10/20/40 lp/mm) across the image\'s diagonal.
Aug 28, 2012 at 07:24 AM
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