Thanks Jim. Something to keep in mind when going for that ultra fine grain texture for your GG. When you grind your gg ultra smooth with AO in order to remove as much grain as possible there is a point where the grain gets so fine that a new set of problems begin to increase.

1)Increase in the diffuse quality of the image

2)Increase in light loss

This is one of the reasons why I decided to make a new adapter that has a moving GG.

In order to get over the two above problems the "ideal" static gg would not be made with AO but be a series of random microscopic pits. Each pit could be a miniture cylinder with refective interior sides and a textured glass bottom. This design would be the ultimate in contrast in grainlessness. Each one of these pits would have to be smaller than the CCD's pixel and randomly layout right next to eachother in order to avoid a morray effect. Millions of these pits would make up a small focusing screen that would measure not much larger than 40mm across. These pits could be cut by a laser enscriber but how your going to get that mirror finish is beyond me. Perhaps you could go without. Remember laser enscribers are able to etch company logos with perfect accuracy on the edge of a diamonds surface so small that a 100X microscope is needed to see it. There is little doubt in my mind that this would be the "ideal" focusing screen but then again what is ideal and what is within our means are often two things. Just though I'd throw it out there for anyone with the resources.

-Brett Erskine

Bob, I mailed you , thanks!

Joel: As soon as I sort out my server, I'll mail a link. A Gaggle of lurkers wiped out my free 5 gig/mo limit on that server!

-Les

How about this for a ground glass and inverting the image

http://porterscamerastore.com/Merchant2/merchant.mv?Screen=PROD&Product_Code=19-0116&Category_Code=V1D

I've always wanted to see how good that screen looked. Just so you know while it will beable to mirror the image left/right back to normal it will not flip the image right side up again. Someone buy one and post a high res video.

I have one and got it to transfer 8mm to DV.
I will not use it again even for 8mm/16mm transfer.
The grain is LARGE, glass type bubbles on the backside and shows up as if it is dirty.

yesterday i dismounted another LCD screen from a laptop and found (no surprises) the usual set of thin sheet of plastic.
two are kind of transparent stuff that are not transparent (weird), like fresnel. no use for us but two others are frosted plastic , one half transparent , the other one totally opaque.
both have a finer grain than the previous sheets i found in other LCDs. I think they would not fit for static gg (grain is close from what you get from an average gg), but would have no match when used for orbital gg. The sheet is very thin and a small part of it will have almost zero weight, so no inertia to compensate.
Additionally you can just cut it at any size or shape with a simple cutter (mounted in a 35mm slide frame ?)
I will make some test and load picture if i got time (playing with HD now ;-) ).

please keep me posted on the tests with the LCD stuff!

If you Google around a bit for technical papers to explaine how these different sheets in a LCD system work). Try 3M, go to sid.org and try the manufacturers links (Sharp, and probably Casio, have papers, but it is notoriously hard to track them down as Sharp is spread accross so many websites, and are hard to search (I find Phillips, worse they should look at getting their UK programmers to do the world headquaters sites)).

Go to google, lookup www.handheld2000.org and use their cache feature and look through for links to LCD and display stuff, and the bookmark file posted their (has some links to LCD papers).

Look through my posts on the two main adaptor threads and three original home cinema camera threads, I might have posted some links to some papers there.

Some of this tech would be helpful, but feature size will depend on resolution, and has to match the format being used (35mm MF), so ordering directly from the factory might be a better move.

Thanks

Wayne.

New page of full res pics and footage from my GL1 adapter here.

This footage is straight from capture with no cleaning, color correction, cropping, etc. All shots were taken more or less at f 2.0, 1/250th shutter, no gain. Time of day was late afternoon, 3-4pm.

As mentioned before, I need to update the tutorial's text to reflect new lessons learned, and will do so soon(ish).

And yes, Les, Brett, et al -- I see the grain and don't care :P :D Looks good enough for me (note: there's no blooming and I'm not using a condensor!)

- jim

- Jim

It looks great. I've reached the point where I no longer care about the grain either. Kinda charmy in a way. And you can do some post production to get rid of it.. a good way is too put a little noise on the footage wich will distract your eyes from seeing the static grain, and I also duplicate the footage and have one layer "gaussian blured to strength around 4-6" and with opacity around 20% that takes away the static grain and even gives the film a more film-looking feel.

great work. i'm downloading the pans and racks raw msdv ntsc files now :)

Jim. A quick question.


Is the GG 3 Micron?

What size image frame were you taking off the GG?

Oh well it was two questions.


As for static grain, I could live with what you have there also. I think that provided there are no larger spot defects on the GG texture to spoil the even-ness, it is an aesthetic not unlike the use of different papers or canvasses in drawn and painted artwork.

As for the larger defects, I seem to recall stains on cinema projection screens from misguided cleaning attempts and the odd spider's web or two.
Can larger video projections systems resolve the grain??

Eric,

Thanks for the post advice. I'll look into your suggestions.

Bob,

It's WAO5 from gotgrit.com. If you know of a reputable 3 micron distributor, I'd like to know of it, too -- while I'm content with the image as is, I wouldn't mind trying an even finer grain. This GG took me about a half hour to produce -- if you do it right the first time, and avoid deep scratches, grinding is pretty much a headache-free affair -- so another half hour wouldn't kill me.

As for the image size, I don't know that answer. All I do is lock my Nikon lens in on an infinite focal length, point the camera at an evenly lit surface with hard edges (black text on a white background is good), and adjust the zoom and focus ring manually on the GL1. I get it just out of focus and then tap the telephoto rocker back until it get's everything sharp again -- then I check the edges for blooming and, once I've got it set right, slide the camera into 'lock' mode. Then I'm ready to shoot.

- jim

Jim.

Thanks for the info.

I'm using 5 micron. Because I was using a machine I was able to work the mix to exhaustion to get a slightly finer finish but found it became too transparent with hot spotting and ghosting (too much aerial image coming through the projected image).

I returned the disk to a new 5 micron mix and stopped it before it began to fine up. I tried a backpolish on wool felt and Cerium Oxide for 10 minutes which seemed to improve light transmissability a little without losing the opacity.

Instead of a glass polishing surface I tried several metals and found a machined face on flowcast bronze worked best and did not dig scratches into the glass.

I was told cast iron is okay but there must be a special grade because there were very many bad scratches from the piece I used.

Aluminium just didn't work well at all, too much metal and sticking.


I am shooting the 18mm x 24mm image frame which makes the grain larger. The relay lens set I use does not permit a larger projected frame.

small bright spots
 

Hey guys!

I've been grinding a GG for a static adapter with 5 micron, and everything has been going great, until yesterday, when I discovered that my camera picked up very small, white spots when I was aiming at something bright ( like a spotlight, or a window in daytime ).

My guess is, that the light makes the grain shine up, in a way .. Am I right?

Is there any cure for this?

Try a ND or polarizer on your 35mm lens?

- jim