Below...
Regards, Bob... ------------------------------------------------ "A picture is worth a thousand words, but it uses up three thousand times the memory."
From: "mike wilson" <[EMAIL PROTECTED]>
Bob Blakely wrote:
I have some difficulty understanding this. Glass (even a Coke bottle bottom) has no ability to produce any discrete divisions in intensity, nor does it have the ability to compress the luminescence scale. Film does. Paper does. Digital sensors can. Sucky digital processing can. Glass doesn't. Now, one may have excess flair that can mask fine gradations at the dark end and give a muddy look...
Glass indeed does have the ability to compress the luminance scale. If you're saying what I think you are. It's what filters do and filters are basically coloured glass. BUT all glass is coloured. Some of it just looks less coloured to us. It's the differing qualities of glass in lenses, besides their optical formulation, that gives them their characteristics.
No. What we are talking about here is not a selection of spectrum (which is what filters do), but a compression of the dynamic range of light level. Glass does NOT compress the dynamic range of the incoming light.
A perfect reproduction imposes no transitions from light to darkness, any discernable transition would come from the nature of the subject and it's lighting alone.
Not correct. I suspect you mean stepped transitions. Even then, not correct.
No. Correct. Just as in music, the goal of faithful reproduction is that it be, well, faithful. None of the equipment in a perfect sound system imposes any distortion, noise or color of it's own. What you hear would be exactly the same as what had been recorded. All the nuance of the music comes from the musicians, not the reproduction equipment. Now, from there you may wish to muck around with the sound using a graphic equalizer and/or black boxes to change the "ambiance", but no one says the microphone that records the music should compress or expand the dynamic range. The same is true of the lens in photography.
If you see high contrast, but the transition from light to dark appears too narrow such that the fine smooth transition from light to dark is not discernable, I'd say look to something other than the lens.
There are indeed other factors that may cause this but lens contruction is a perfectly possible one.
Bullpucky!
