Originally posted by y0chang
Digital sensors have micro lenses that gather light at oblique angles. Film lenses are not optimized for these micro lenses means that there is a loss of resolution and vignetting.
Yes and no. In fact the photosensitive particles on film are able to gather light from many directions, that's true. And microlenses are trying to emulate this (and mitigate the fact that CMOS sensors have non-light sensitive components at the surface). Without saying they're equal, they're actually pertty close, and certainly closer than what they were before they used microlenses.
Originally posted by normhead
I've never seen any quantifiable data suggesting film and digital sensors have to be different.
They don't have to, regarding angles. They certainly are, regarding wavelengths.
Originally posted by normhead
The common practice of releasingf specs based on analysis of the design by a computers certainly would suggest not. It would suggest they aren't even doing testing on the actual product, but using numbers of un-known reliability.
I've never worked on a photo lens design lab, but I'm an optical designer. You are correct that designs are done via a computer. These designs, when well made, take into account flaws in materials, manufacturing tolerances, and many other elements most users would never even think about. THEN they are (or should be) tested via prototyping, "beta" iterations, pre-production samples, and performances qualification.
"Numbers of unknown reliability" is an expression which makes no sense to me, especially in this context.
Originally posted by normhead
That being said, those of us who use film area lenses have to be sensitive to conditions that might cause purple fringing, which apparently was not an issue on film.
All of my film era lenses purple fringe more than my more modern designs.
Digital sensors are more sensitive to UV light than film. That's why PF shows often with older lenses. PF is in fact a manifestation of CA, but for wavelengths that our eyes (and film) don't see while the sensor does. It should be filtered out before reaching the sensor, but that's not always the case. I suspect most recent camera designers stopped caring bout it because the lens designs nowadays take care of it. With older lenses, that's not the case, but camera manufacturers want you to purchase new lenses, so there's no incentive for them to optimize for old glass.
Originally posted by aslyfox
My SMC Pentax-FA 77mm F1.8 arrived today
Your latest acquisition - PentaxForums.com
where are the cookies ?
This is what I could gather on short notice. I might be able to do better over the weekend