Tinted glass

Has any one here used a tinted glass like PPG's Solexia (with a 77%
transmission rate) instead of ground glass for large format focus?

Regards,

Marv

"Marv Soloff" wrote in message
...
Has any one here used a tinted glass like PPG's Solexia (with a 77%
transmission rate) instead of ground glass for large format focus?

Strange. May I ask Why? Most of us want all the light we can get, and
besides GG is inexpensive, quite available and bright. In fact, if you put a
drop of oil right in the center of the ground side, you have a brilliant
point for aerial focus.

Working on a scanner back for a large format camera (odd sized). Idea is
to use a standard scanner minus the illuminating tube as a pickup at the
focal plane. Static shots only. Wanted to explore the options other than
GG - which I make myself with valve grind compound. I thought I would
have problems with the CCD pickups and ground glass hence the thought to
use a tinted film or glass.

Regards,

Marv

jjs wrote:
"Marv Soloff" wrote in message
...

Has any one here used a tinted glass like PPG's Solexia (with a 77%
transmission rate) instead of ground glass for large format focus?


Strange. May I ask Why? Most of us want all the light we can get, and
besides GG is inexpensive, quite available and bright. In fact, if you put a
drop of oil right in the center of the ground side, you have a brilliant
point for aerial focus.

In article ,
Marv Soloff wrote:

Working on a scanner back for a large format camera (odd sized). Idea is
to use a standard scanner minus the illuminating tube as a pickup at the
focal plane. Static shots only. Wanted to explore the options other than
GG - which I make myself with valve grind compound. I thought I would
have problems with the CCD pickups and ground glass hence the thought to
use a tinted film or glass.

OH! Thanks for answering. Sounds like an interesting project. I had the
idea that flatbed scanners actually focused upon the aerial image, but
what do I know?

On 1/23/2004 5:49 PM Marv Soloff spake thus:

Working on a scanner back for a large format camera (odd sized). Idea is
to use a standard scanner minus the illuminating tube as a pickup at the
focal plane. Static shots only. Wanted to explore the options other than
GG - which I make myself with valve grind compound. I thought I would
have problems with the CCD pickups and ground glass hence the thought to
use a tinted film or glass.

Wait a minute--I must be misunderstanding something he how could the ground
glass, or anything else, interfere with the CCD? Wouldn't you use this like a
conventional film camera, in the sense that you first focus on the ground
glass, then replace the GG with the CCD (or slide it in under it like a film
holder)? What am I missing here?


--
Focus: A very overrated feature.

- From Marcy Merrill's lexicon at Junk Store Cameras
(http://merrillphoto.com/JunkStoreCameras.htm)

On 1/23/2004 6:06 PM jjs spake thus:

In article ,
Marv Soloff wrote:

Working on a scanner back for a large format camera (odd sized). Idea is
to use a standard scanner minus the illuminating tube as a pickup at the
focal plane. Static shots only. Wanted to explore the options other than
GG - which I make myself with valve grind compound. I thought I would
have problems with the CCD pickups and ground glass hence the thought to
use a tinted film or glass.

OH! Thanks for answering. Sounds like an interesting project. I had the
idea that flatbed scanners actually focused upon the aerial image, but
what do I know?

Now I get it. Had to go back and re-read his message.

I don't think scanners focus on an aerial image--they focus on a physical
image, at the other side of the glass. But even if so, is there any reason
they couldn't focus on an aerial image? So long as the image (aerial or
otherwise) is at the plane of focus, does it matter?

(Shows how much *I* know about optics.)


--
Focus: A very overrated feature.

- From Marcy Merrill's lexicon at Junk Store Cameras
(http://merrillphoto.com/JunkStoreCameras.htm)

The idea here is to use the scanner and work forward via bellows to lens
assembly. I want to have the tinted sheet at the "film plane" and
allow the scanner CCD bar to pick the image off it. Some very
rudimentary tabletop tries here indicate to me that the GG was not the
best way to go, hence the interest in tinted glass. Remember, we are not
dealing with film here, but something totally different. And, since I
don't really know what I'm doing, I have to try everything empirically.
Just wondered if anyone had tried tinted glass instead of ground glass.

Regards,

Marv


David Nebenzahl wrote:
On 1/23/2004 5:49 PM Marv Soloff spake thus:

Working on a scanner back for a large format camera (odd sized). Idea
is to use a standard scanner minus the illuminating tube as a pickup
at the focal plane. Static shots only. Wanted to explore the options
other than GG - which I make myself with valve grind compound. I
thought I would have problems with the CCD pickups and ground glass
hence the thought to use a tinted film or glass.


Wait a minute--I must be misunderstanding something he how could the
ground glass, or anything else, interfere with the CCD? Wouldn't you use
this like a conventional film camera, in the sense that you first focus
on the ground glass, then replace the GG with the CCD (or slide it in
under it like a film holder)? What am I missing here?

On 1/23/2004 7:12 PM Marv Soloff spake thus:

The idea here is to use the scanner and work forward via bellows to lens
assembly. I want to have the tinted sheet at the "film plane" and
allow the scanner CCD bar to pick the image off it. Some very
rudimentary tabletop tries here indicate to me that the GG was not the
best way to go, hence the interest in tinted glass. Remember, we are not
dealing with film here, but something totally different. And, since I
don't really know what I'm doing, I have to try everything empirically.
Just wondered if anyone had tried tinted glass instead of ground glass.

So what do you think of the idea of just having the CCD focused on the aerial
image--could this work? I'm sure someone here with more knowledge of optics
than me could answer this.

Anyhow, sounds like an intriguing project that ought to keep you out of
trouble for a while.


--
Focus: A very overrated feature.

- From Marcy Merrill's lexicon at Junk Store Cameras
(http://merrillphoto.com/JunkStoreCameras.htm)

There have been a number of "scanner-direct" articles on the net. Most
involve removing the pickup components and using a lens - somewhat like
the old Cirkut cameras - where the CCD assembly (remember this is a long
bar not just a round spot) moves with the lens. Not what I had in mind.
What I wanted was to produce a stationary image the size of a scanner
pickup plate and scan that. Probably produce a huge (100+ MB) image file
if I can get it to work.

Regards,

Marv

David Nebenzahl wrote:
On 1/23/2004 7:12 PM Marv Soloff spake thus:

SNIP

So what do you think of the idea of just having the CCD focused on the
aerial image--could this work? I'm sure someone here with more knowledge
of optics than me could answer this.

Anyhow, sounds like an intriguing project that ought to keep you out of
trouble for a while.

In article ,
Marv Soloff wrote:

There have been a number of "scanner-direct" articles on the net. Most
involve removing the pickup components and using a lens [...]

You guys are a bad influence. It's the dark of winter. Cabin fever sets
in. There's an Epson scanner on the desk, and I have several very large
(wide, fat) lenses. Heh. Revenge. I'll do self portraits as example
pictures.