I know this is straying from the original intent of the thread.
The High Refraction Index plastic lenses used is eyeglasses are nowhere near
photographic quality. They do not refract evenly across the visible
spectrum. They are close enough that the older folks who usually buy them to
avoid wearing coke bottles do not notice it because they have already lost
the ability to see the outer edges of the spectrum.
This is easy the check if you yourself have good color vision, go to the
store and look at one of the blanks. View some black text or lines on white
paper through them. You will see a visible reddish-orange ghost hugging the
top of the black text or lines and you will see a blushish ghost hugging the
bottom edge (possibly I have my colors inverted).
I recently (6 months ago) allowed an optometrist to talk me into a set of
these because it was getting hard to get the blanks for the large frames
that I like to use (translates to out of style). I refused to buy the new
teeny tiny frames that are getting popular.
It took me the better part of a day to realize what was wrong. As a
publisher it was driving me crazy when I was looking at the pulls off of our
printing presses. I had to go to a loupe to check stuff.
They replaced the lenses with glass, but it took time to get them in.
Just as folks with less discerning vision will accept that flaw in their
glasses. The masses of our disposable, P&S society will accept whatever the
plastic lens will do. I was at a wedding not too long ago where they put
disposable Kodaks on the tables instead of paying the wedding photographer
to shoot the reception AND THEY WERE SATISFIED WITH THE RESULTS.
These same people walk into my office and comment at how great the photos on
my walls look, 20x30s and 16x20s all captured with Zuikos. Then they ask me
why their pictures do not look that good, after all they switched to an
Advanced Photo System camera, shouldn't it be better than a 35mm? OK so it
was $35 with three boxtops from their favorite cereal, but it is APS.
Mark
----- Original Message -----
From: "Jeff Keller" <jrk_om@xxxxxxxxxxx>
To: <olympus@xxxxxxxxxxxxxxx>
Sent: Saturday, July 19, 2003 1:03 PM
Subject: Re: [OM] Plastic Lens question
> Lens Crafters sell plastic eye glass lenses that are thinner than normal
> glass lenses. The high refraction index glass lenses are possibly
> slightly thinner but you would have to have them side by side to tell
> which was thinner.
>
> As Garth said index of refraction doesn't determine the resolution of
> the lenses. I believe higher index glass often had/has more variation in
> the index vs. the light wavelength (aka dispersion) but it was many
> years ago when I was probing into this and my memory is far from
> perfect. Matching dispersion characteristics of different materials for
> different lens elements is done to give better performance and adds to
> the vocabulary: achromatic, apochromatic, ...
>
> -jeff
> ----- Original Message -----
> From: "Albert" <olympus@xxxxxxxxxxx>
>
>
> >
> > I know based on glasses; glass is less than 1/2 as thick.. So I don't
> > know if that's linear or exponential, but that should mean that it at
> > least resolves 2x as well vs. plastic??
> >
> > Albert
> >
>
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