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-   -   Mini 35 Competing Unit for a Lot Less $ (https://www.dvinfo.net/forum/techniques-independent-production/10532-mini-35-competing-unit-lot-less.html)

Joseph George July 3rd, 2003 01:45 PM

I got bunch of private emails -- I was out of middle of nowhere and except for email did not have real Internet access. Thanks. What I was going to send Cosmin was the info on ground glass. Here it is for everyone. Both the Mini and the Pro units have circularb GG's. It looks like a filter and it is in a filter-like barrel. Edmunds Scientific sells ground glass. They are on the web. Get the finest GG you can get.

John Jay July 4th, 2003 03:24 PM

Cosmin,

it looks to me that (in after effects terms) the gg is displacement mapping the original image at the film plane (especially your non vibrating gg cuddly toy pic)

i wonder if a physical engineering solution is the most cost effective way ahead?


maybe if the gg signature was known (as a greyscale image) an inverse displacement map could be achieved in after effects? so the gg distortion could be illiminated in post.

an experiment to determine gg signature would have to be devised of course (not easy but a once off solution)

it makes me think that the superb Takumar lenses M42 thread could be used, screwed on to an M42 fixed length extension tube with the gg contained inside the tube, then screwed via step ring to virtually any cam with macro function and less than 42 thread

Cosmin Rotaru July 7th, 2003 01:17 AM

Hmm... The inverse displacement map sounds good in theory. I don't know how to do it, though... Could you use a pic for the displacement map?

Elmar Tewes July 7th, 2003 03:02 PM

i finally found something that looks really interesting...
http://www.movietube.com/
it seems there is another company who brings out his version of a dv - 35mm system - perhaps a lot cheaper than the p&s technik one ???

Jaime Roman July 7th, 2003 10:15 PM

i found a few more pics of movietube online at this site:

http://www.buero-hahn.de/2work/iprojekte.htm


Only problem is, how does it work?

Joseph George July 8th, 2003 12:14 AM

Very interesting. Does anyone speak German to translate this stuff?

Cosmin Rotaru July 8th, 2003 02:25 AM

very interesting, indeed!


I tried an online transaltion (nothing interesting):
"The Movietube is an accessorie for miniDV cameras in order to simulate the Videodrehen the Tiefenunschärfe of real cinema films. The Flash animation on the CD-ROMS generated for a patent competition is actual component of the Movietube homepages that goes soon Online. For the competition, the presentation in Flash was modified for the use as an alone standing program on a CD something. Soon there will be the total presentation and to see more Online. Beforehand here schonmal a couple Screenshots of the CD (to the Vergößern please simply on the picture click)"

Jaime Roman July 8th, 2003 07:43 AM

This is the translation i got for the beginning of that statement

" The Movietube is accessories for mini digital video cameras, in order to simulate with video tricks the depth and sharpness of genuine motion picture films."

John Jay July 8th, 2003 11:25 AM

Cosmin

I have two proposals to consider one is software related and the other is physical, i shall start with software

taking your clear cuddly toys pic (straight from video) and displacement mapping it with a greyscale noise pic in photoshop would produce an image quite similar to the stationary gg pic of the cuddly toys, provided the displacement factor was set to a suitable value.

So in effect, the displacement of pixels of the clear pic is proportional to the intensity of the grey value of the pixels in the noise pic. This process is reversible (try it) since taking the displaced pic from above and displacement mapping it again but in the opposite direction (negative dispacement factor) would produce the original clear picture.

ok so far?

what is required is to generate a greyscale noise pic which corresponds to the effect of the stationary gg. Some experimentation is required. The following is only a suggestion.

A good start would be to generate some fine black vertical lines on a sheet of white paper (thickness of the lines =space between them) and to measure how much they are horizontally displaced after passing through your stationary gg rig (I expect some zooming in will be required). The result of this will deliver the horizontal noise component of the gg

Next repeat the above with fine black horizontal lines to deliver the vertical noise component of the gg

Then composite the horizontal and vertical components into a single greyscale noise pic which in theory should be the noise signature of the stationary ground glass

bear in mind the resolution of the noise pic should be one pixel, which is tedious i know , so it may be best to concentrate on a small area to check that it works in practice.



my second proposal is a possible physical solution

Consider that your 35mm lens (from your rig) ultimately will be attached to a fixed length extension tube. Now with a circular saw cut a slit in the extension tube perpendicular to its axis at the point where the filmplane should be but not all the way through.

Make a circular disc gg of say CD proportions - a CD gg!

Spin the CD gg at high speed (5000 rpm is possible) through the slit created above by means of a motor mounted on the outside of the extension tube, this should sort the distortion problem and reduce the need for high quality ground glass. (maybe running the CD gg at slower speeds might introduce some desirable grainy effects)

Maybe the CD need not be ground glass at all but just radial score marks if it spins fast enough

A final design would have a housing for the CD gg and motor and would look a bit like a 'machine gun kelly' type of rig if you have understood me correctly

Cosmin Rotaru July 9th, 2003 01:47 AM

Thanks for the ideas, John.

Actualy, the second one I already tried a few days ago. I have a small (about 1.5MB) clip that I could send it to anyone interested. But only tomorow because I don't have it at me (sorry Elmar, I forgot...). The image is better than with the vibrating stuff.

The first idea is somnething that I have to test. I didn't relize is so complicated! The first time you mention it I thought I'd just take a pic at a white paper to see the grain... I din't think of the vertical and horizontal lines.

I'll let you know how it works.

John Jay July 9th, 2003 07:03 AM

please send it

krisp9@yahoo.com

Jaime Roman July 9th, 2003 10:23 AM

Hey Cosmin,

Please send me that clip also to -- romanemp@aol.com.

Are you also a member of the homebuilt stabilizers forum? I believe i just finished answering a question you had on aluminum alloys.

Cosmin Rotaru July 9th, 2003 10:53 AM

Thank you Jaime! Yes, that's me! :)

Spencer Houck July 11th, 2003 09:51 AM

Could you send the clip to me also?

And, sorry if you have said this, what camera are you using? Seems everyones working on Xl1 35 adapters, but i'm "stuck" (terrible thing to say about a purchase as major as this one was for me) with my Sony VX2000, and would love to see some headway in that department.

Thanks for the clip and inspiration. I'd love to get back to Ohio University next year and blow some ppl away with any ressemblence of shallow DoF. :)

shouck@neo.rr.com

Cosmin Rotaru July 11th, 2003 10:47 AM

I've sent you the clip, Spencer. I've sent the clip to anyone who ask for it!
I already received some feedback on my e-mail. Thanks! It seems that the image is nice, so I'll continue experimenting. I'm not going to try eluding the existing patents and make something for sale. I just want to make something for me... But I'll help anyone who whants to build their own.
I own an Canon XM2 (that's the European version of the GL2).

I like very much how the movietube looks! The adapter looks nicer than the P+S one. With shoulder support, viewfinder, XLR adapters... A complete accesory for miniDV.

I expect prices going down from now, as there's competition. I realy don't understand how could they ask 8000USD for an accesory made for a 3000USD camcorder...


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