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 (http://ideaspora.net/aldu35/images/screengrabs/).

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.

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

after further experimenting, I found that it was the other side of my condenser that was causing it .. any bright light would make the smallest particle visible, or fingerprint

I'm going to try rearrange my two condenser lenses like this
(the second condenser is the one with the GG .. )

SLR Lens - [)(] - Camera

That way, no dirt or fingerprint will shine up like it did in my other arrangement below ..

SLR Lens - (][) - Camera

Am I missing something? When trying that new arrangement, I can't see any optical distortion, so I guess it's working .. ?

tja martin!

just wanted to let you know that i've ordered 2 pcx-lenses, a fresnel lens and a GG in plastic. i will let you know how the fresnel is.. and if the GG is any good. i can't wait til i get these stuff. i hope the fresnel lens is good. that's the lens they use on real GG to get rid of vignetting (you know the guy on voodoofilm who shot through his F4, that viewfinder was a GG with fresnel-lenses on both sides).

i'll let you know later this week.
but hey... hows the GG's coming? you don't feel scanning a GG in high res, like 1000x1000 or something? would be great.

---------
your condenser lens experimentation... why would fingerprints be more visible the way you had it before?

TO EVERYBODY-
is there any software wich will show you how light goes through lenses... that way we could see the difference in (| |) and |) |( must be some software out there... where you're able to see the "light curve"

heey eric!

Sounds great! Keep me posted on your progress with the plastic GG ..

My GG is doing great! .. As I said before, I've been grinding one of my condensers, and now after 4 hours + of grinding, I don't think it'll get any better.

Today I tried my theory .. I flipped the condenser, and yes, those irritating bright dots disappeared, BUT .. instead I got some wonderful vignetting .. ! jippi! .. I should have foreseen this .. : /

So, when undoing everything I just, the backlid of my Canon FD lens poped out along with springs and other delicate stuff .. i must be cursed, or something ..

So, back to the first issue .. I guess I'll need some ND filters, and really watch the lighting when shooting, cause there is no way in *beep* I can keep the back of my condenser that clean .. how are guys dealing with this? ..

Mount your condensers in filter rings, clean them perfectly then sandwich them bewteen two Skylight filters.

Make sure the gap between skylight filters and the GG is far enough to put any dust they get on them way out of focus.

2nd option: Make a vibrating adapter.

- Martin

Did you grind a condenser lens on the flat side!?!

yes, eric, I sure did! :)

anyway, here is a picture of what I am dealing with !

http://www.martin.incmplete.com/mini35/dirt2.bmp

and ..

http://www.martin.incmplete.com/mini35/dirt4.bmp

now, it's really, really hard to see these things in a picture , but look at the bright spotlight to the right .. around it, there are small white particles ..

Actually , Brett .. I am considering building me a oscillating adapter .. I was thinking about making it squareish, with 4 shafts and one motor .. don't know if it'll work, though ..

"Actually , Brett .. I am considering building me a oscillating adapter .. I was thinking about making it squareish, with 4 shafts and one motor .. don't know if it'll work, though .. "

Yeah that will work...at least it worked with mine.

-Brett Erskine

<<<-- Originally posted by Brett Erskine : Yeah that will work...at least it worked with mine.

-Brett Erskine -->>>


Hey Brett... do you have any pictures of the rig and result? I definately want to see it.

And Frank Ladner..where are you?
Hows the microcrystalline wax coming?

Eric: Hey! I still read the forums almost daily, but I haven't had time to work on the adapter at home due to side-jobs. You know how that goes. I haven't given up on the project, though.

Im in the same boat as Frank. I'll post it when its all done and well tested.

LOL, I leave for 6 months from the site and I see you all are having the same issues. Not a whole lot of forward movement in the last 800 posts. Oh well...have fun building!

John, I posted some examples of mine device working at HD resolution. Still not perfect, but there is no grain.
I don't need the artsy-fartsy grain effect.
Email me if you would like a link to the 25 megabyte full res test clip, it's only a few seconds long.
-Les


<<<-- Originally posted by John Gaspain : LOL, I leave for 6 months from the site and I see you all are having the same issues. Not a whole lot of forward movement in the last 800 posts. Oh well...have fun building! -->>>

i want to see it!
mail to: eric-ohmanATtelia.com

i can host it too if you want... i have 300mb.

<<<-- Originally posted by Les Dit : John, I posted some examples of mine device working at HD resolution. Still not perfect, but there is no grain.
I don't need the artsy-fartsy grain effect.
Email me if you would like a link to the 25 megabyte full res test clip, it's only a few seconds long.
-Les


<<<-- Originally posted by John Gaspain : LOL, I leave for 6 months from the site and I see you all are having the same issues. Not a whole lot of forward movement in the last 800 posts. Oh well...have fun building! -->>> -->>>

cool! I'll search your name for posts to see what you did.

thx

Les,

Could you send me a link to your footage? I'm at raeshao@comcast DOT net. Thanks a lot!

Brett I am still waiting for an answer from you about testing your unit with the HD camera I am building..would you care to email me at

oolsen1@ec.rr.com


thanks a lot!

Sure thing. Sorry about that. Check you mail box.

Any sample footage yet, Brett ?

-Les

Sorry to leave you hanging. I've been busy working alot lately so I've been forced to put the project aside. The very day its showable I'll post it on here.

Folks,

I am about to go into a design meeting with a design and prototyping company here in Salt Lake City to see about developing CAD drawings and data files for CNC and 3D printing machines.

I have read every message on this thread, many twice (for you Brett!) -- However, I was not able to find a final concensus on the design regarding the use of Micro focus screens (without markings) and/or the need/quantity of condenser lenses and their orientation?

If anyone can help me out here in the next hour, I would appreciate it. If you have specifics, please email them to me directly. I will post later this afternoon or tomorrow the results from our meeting.

km

After extensive experimentation and sizable investment into the test equipment/parts, I have come to the following conclusion:

- The quality of the video with even the best of the adapers (be it self-made or P+S pro system) is subpar to the extent that I consider unacceptable.

Note that I operate HDV cam, not SD DV. However I have the same opinion of the adapters in DV applications as well, sorry.

Therefore I stopped experiments. At this time, there seems to be no way to have a reasonably priced 35mm adapter for DV or HDV cams that produces no visible image degradation.

I guess the best bet is to wait for the HD/HDV cams that may feature large, 35mm-alike sensor areas so 35mm lenses (primes or zooms) could be used on their bodies interchangeably.

Until then, I'll just stick with the original lens system on my HDV cams. There's no room for further image degradation as introduced by the adaptors, in my opinion.

The quality of the video with even the best of the adapers (be it self-made or P+S pro system) is subpar to the extent that I consider unacceptable.

Thanks for your insight -- so long!

- jim

I've recently finished a feature length film to be exhibited at San Sebastian and Cannes.(official competition)
It was filmed with a Pana DVX100+Mini35.
It looks really nice.We couldn't find the image degradation you are talking about and it looks really amazing after transferred to 35mm.
Don't know about HD cameras with the pro adapter.It is always the same, some people say it is ok some other say it is a no go.
What really counts is what you see at the final stage I guess....

Alex, other than the slight vibration from my temporary setup, what was the image degradation you speak of from my mini35 type GG orbiter ?
My JVC HD 720P test , that I posted, didn't seem to reduce the resolution more than a few percent.
Perhaps you got burned out with all the grinding elixirs and magic methods that all show grain, especially on HD ?

It is interesting to note that the crazed postings from the 35mm adapter folks has faded away for the most part! Very few posts of working setups in high quality video.
Let me know if you need a link to my sample video.
-Les


<<<-- Originally posted by Alex Raskin :

Note that I operate HDV cam, not SD DV. However I have the same opinion of the adapters in DV applications as well, sorry. -->>>

My own subjective sense is that for HDTV, all the home-made flavours of MINI35 will fall short.

For MiniDV however, I am a little less jaundiced. The spinner version as primitive as I have made it yields 530 TV lines on a test chart which is the resolution wall as far as a PD150 is claimed for. With a better relay path than my telescope eyepiece, the result should be better.

The apparent resolution of normally aquired imaging direct into and from MiniDV appears to be sharper than an AGUS35 image.

How much of this is related to straight edges produced by the pixel rows? Put a highly contrasted finely textured MiniDV image up on a high resolution monitor and it looks dreadful.

What I have learned about the AGUS35 version I have made is that I need to pay far more meticulous attention to focus and the aperture setting/ND filters of the objective lens and relay path if I want the results.

Juan, Les and Bob: the pro adapters I've seen do introduce either grain, flicker, or both, at least under some conditions.

Static adapters introduce grain, light diffusion, or both.

No go.

I have to make the admission that subjective opinions from viewers totally not into the making of images have been that something was "wrong" with my Agus35 imaging. That does raise a flag for me.

Certainly, it doesn't remain consistent enough with non Agus35 imaging to intercut unless a different image style is deliberately chosen to distinguish certain portions or moods within a presentation. That then makes it a useful complementing tool.

It is also useful for creation of an entire presentation if a particular look is sought.

Horses for courses. From VHS through to 70mm motion film imaging.

Hi Les,

I'd be interested to see the sample footage if that was an open offer.

I was following this thread for a while back, there was talk of a holographic material for the GG but I never heard how it turned out. I guess it didn't work?

Cheers
Dan

For 35mm SLR still camera lenses, investigate the Carl Zeiss Jena lenses for Canon T50 or similar. The Jena-Zoom seems less inclined toward hotspotting than others.

Sorry if this has been asked before, but do I need to grind with anything BEFORE I start with the WAO 5?

Also, what's the general consensus on how long it takes of grinding with WAO 5 to get a good result?

Thanks.

Steve.

I'm not the resident expert on this subject however my understanding is that if your intended groundglass has already been finished high quality as an optical filter, all you need to do is use the 1500.

Weldeing goggles glass replacements may need more thorough finishing. If low (semi-clear) spots become evident in the 1500 work you may need to go back a grade then re-dress with the 1500, otherwise perservere with the 1500 until they are gone.

Recommended practice is to move your intended groundglass over a fixed dressing surface.

Some people use a sheet of glass. On glass, some problems with pickup or clinging have been reported. This leads to excessive contact pressure which causes scratches and gouges.

A machined piece of bronze or brass as a dressing surface yields a good result. Cast iron is used by the industry but I understand it may be a special grade which does not have hard particle inclusions in it. I found ordinary cast iron scratched my glass. Aluminium was also no good. It caused scratches and wore away too quickly which killed the grit slurry.

Before you commit your intended groundglass to the process, go along to your nearest pathologist and obtain some microscope slides to practice on. These give you a good feel for it. The feel as you work the glass has a lot to do with the results you get. Keep working on the microscope slides until you can achieve a result without gouges or scratches. It is frustratingly pointless trying to do it any other way.

Finally, cleanliness is next to godliness in this process. If you leave the project unattended and you have pets, you can guarantee contamination with dust or house grit in your absence.

Your intended groundglass needs to have a chamfered edge on the intended groundglass side otherwise the edge corner will sharpen, flake off then roll under into the slurry and gouge your glass. You will need to do this to your microscope slides. The intended groundglass will already have a chamfer if it was an optical grade product but check it anyway.

One of those new little diamond laps for sharpening knives is good for this task. Do it under running water.

Recommended practice is to move your intended groundglass over a fixed dressing surface.

Sorry to disagree, but this isn't the case, Bob -- you're increasing the likelihood of scratches and the amount of time required to get a uniform surface this way.

Move your grinding glass over your GG -- in this was you maintain a more even pressure across the GG's surface. It's uneven pressure and dry slurry that cause scratches, and scratches take hours to properly grind out.

Properly mixed slurry and care taken will yield a great GG within a half-hour. Be sure to:

Pre-mix grit and water to ensure a thorough soaking of the grit.

Mix this "paste" with even more water at grinding time (grit to water ratio should be about 1:5, respectively.)

Keep your glass on an even surface.

Check your GG and grinding glass surfaces for dirt prior to grind.

Err on the side of caution when replenishing your slurry -- do it early and often.

- jim

Found an interesting GG. I'm not sure if this has been posted before.

http://www.satinsnowglass.com/index.html

Has anyone used one of these before? If so how was it and how much light does it lose?

Seems promising at least (and probably well known to medium format shooters)

Aaron-

Nice find!. They can cut to any size, dont have any gridelines on it, nearly no grain, and did you check out that price?!

Just ordered ordered one. I'll post my results.

-Brett Erskine

I think my brain skipped. ;-)