[rollei_list] Re: Lens Tests
- From: Don Williams <dwilli10@xxxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Sun, 27 Mar 2005 17:14:38 -0800
At 03:51 PM 3/27/2005, you wrote:
>On Sunday, March 27, 2005, at 03:08 PM, Don Williams wrote:
>
> > I think you can measure lens resolution with an optical instrument
> > placed at the film plane. At least that seems to be how it's done on
> > lens factory production lines, film doesn't play a part as far as I
> > know.
>
>I think you may well be right.
>
>Does anyone have statistics for different lenses such as Xenotar,
>Planar, Sonnar, Summicron, Summilux, Ektar, Canon EF f/1.8 50 mm, etc.,
>when their resolutions are measured in this manner? Surely they are
>more meaningful than resolution-of-lenses figures given by taking
>photographs on actual film, which can be skewed not only by the
>limitations of the film, but also by limitations such as improper
>focussing or the possibility of the film not lying flat in every shot!
>
>The same lens used in the future, with a really advanced digital back,
>may give a much better picture than with film. Right?
>
>
>Ardeshir <http://homepage.mac.com/ardeshir>
The only thing I remember from the olden days, when I had an optical
engineer working for me on an Near-IR Distance measuring system, we
measured lenses and film wasn't involved at all. We measured line-pairs
per mm, however it's clear that ignores lots of aberrations, flair, etc.
The latest "current folklore" I hear is that the best films would require a
24 MP digital back to reach the same "resolution", whatever that may mean
to the user.
I have to admit that after years of reading resolution and distortion
charts from lens manufacturers, I am doing more digital than film. I only
use film when I have a special need. For general use, digital suits my needs.
DAW
Don Williams
La Jolla, CA
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