AW: WG: [Rollei] OT: Acute Matte Screen.. Ebay

["keller.schaefer" <keller.schaefer]

Here is what Prochnow has on how the screens were made:

"... to produce this screen - made of plastic - a copper master needed to be
made (similar to the ones used for (vinyl) disc production. The machine
needed to accomplish the surface structure was developed and built in house.
Millions of engravings in the form of microscopic, optical elements ...were
punched into the master by an 'etcher's needle' whose angle was adjustable.
... This angle modification ... was done purely mechanical ..."

I have also looked at a screen with a loupe and I wish I had a microscope...

Sven

- -----Ursprüngliche Nachricht-----
Von: owner-rollei  us
[mailto:owner-rollei  Im Auftrag von Don Williams
Gesendet: Freitag, 23. Mai 2003 19:46
An: rollei  us
Betreff: Re: WG: [Rollei] OT: Acute Matte Screen.. Ebay


At 07:07 PM 5/23/2003 +0200, you wrote:
>With the removable WLFs came the Rolleiclear screens, a huge improvement
>and - to my knowledge - a 'Rollei First'. These screens replace the ground
>glass (and make the Rolleigrid obsolete). They are made of plastic material
>and have a surface that consists of a multitude of 'microscopic prisms'
that
>give the effect of a matte screen AND the bright edges of a Fresnel screen.
>This technology is the basis for ALL of todays camera screens.
>If I were to rate the screens on a scale from 1 to 10 then the old ground
>glass would be a 1, ground glass plus Rolleigrid a 1.5, Rolleiclear 7 and
>the current HighD screens (and the Maxwells/Beatties) probably a 10. So in
>my eyes, the biggest improvement happened when the Rolleiclear was
>introduced.

Just out of curiosity I took a look at my Rolleiclear with a 10X loupe and
can see, very clearly, concentric rings which would be what one would
expected with a Fresnel design.

At the same time, I see some sort of "roughness" on the surface, most
likely to provide a plane for the image, but at that magnification I
couldn't see the details of this "roughness".

If someone has the time to look at a Rolleiclear with a microscope maybe
the design of this "roughness" would become apparent, but there is no doubt
that there are indeed concentric patterns on the bottom surface of the
screen.

These rings can actually be seen without magnification.


Don Williams
La Jolla, CA

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