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Old July 27th, 2004, 12:44 AM   #1141
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James. Could you post a very short but full res./full screen video of you doing a pan shot of a high contrast scene? Also please share the make and part number of the material that your talking about.

Whats your stop loss?

I havent mentioned this before but at least with GG if its extremely bright it sometimes lets too much light thru and not enough is used to create the image on the GG. The result is a lessing of the shallow DOF look.

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Old July 27th, 2004, 02:59 AM   #1142
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Stuff to Stick to CDs

I gave up on real ground glass when I found single-ply architectural mylar film. It does have grain - at roughly 9 micron GG size, but when spinning it's reasonable. And at $2/11x17 sheet, its much more cost-effective than glass and powder and hours and hours... For me it offers the perfect amount of diffusion, though - my condensor removes all hotspot (very noticeable without the condensor) but my light loss seems reasonable. You can also buy double-matte which is more diffused, less light, etc.

I'd love to find a grainless, yet diffused material to attach to the CD. So far, the mylar film is the best I've found.

What kind of adhesive does your stuff have, James? Does it cause visual problems? (can you see globs of glue?) I'd also love to see some video...
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Old July 27th, 2004, 05:05 AM   #1143
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Erecting Agus35 - first image - very furry as some optical components were hand-held. May soon be found here at www.dvinfo.net/media/hart. Filenames are aguserct.jpg and aguserc2.jpg.
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Old July 27th, 2004, 09:58 AM   #1144
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*Vinyl* Material

Jonathon, the material comes with the adhesive. It's made to mount directly to glass outdoors or indoors. We've had this vinyl on the front door of our office for 4 years facing the west and there's been no UV discoloration.

I'll post some pics and video tonight. I've been testing with a high resolution monitor (SMTPE). The monitor picked up the spinning grain on the pre-frosted cd from Maxell. The AO1000 cd had a hot spot (probably needed more grinding). But the vinyl etch was perfect. (and I mean perfect).

Brett, the stop loss is no worse than the frosted cd or AO1000 cd.

I've got the mylar film as well but the grain is too big.

The vinyl material seems perfect so far. Just peel and stick. You can probably find similar materials at sign stores on the web. Just be careful because I've seen some etch look vynl with more grain and 'sparkel'. My vynl grain is very fine. And seems to be scratch free (so far).
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Old July 29th, 2004, 02:03 AM   #1145
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If anyone if doing the prism erector and basing anything on my side-view layout - stop. Go no furthur for the time being as the drawing is WWWWRRRRRONNNGGGGG.

The prism hypotenuse faces are 56mm not 52mm as drawn and this messes up a few assumptions in terms of where they go in the image tube. They still work however. I have also misread the vernier on the disk diameter by 10mm whilst back engineering my clamps-and -gaffertape prototype onto the diagram.

Onto a 4:3 academy frame onto a fixed groundglass the image is as sharp as the non-inverter but there is a slightly more noticeable hotspot. This is best alleviated by positioning the prism block as close to the groundglass as it can be placed without the window frames in the block themselves drawing in upon the image as you zoom in.

I am using 7+ which is not an achomatic diopter. I shall get one as soon as I can. A 52mm diameter may fit by one of the prism retainer bars which will enable a closer couple than the 55mm from camcorder to image plane current available. This will confer the benefit of less zoom therefore slightly less light loss.
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Old July 29th, 2004, 01:39 PM   #1146
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James can you post some pictures and how much do you want for a small piece (enough for 4 CDs) of the material?
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Old July 29th, 2004, 01:57 PM   #1147
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Post Vinyl Shots

I'll try to get to that tonight. Now that I've got the GG solution resolved, I'm finishing up the rails and packaging.

Ernest, I can hook you up with a peice.
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Old July 29th, 2004, 09:40 PM   #1148
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James-
Did you get that make and part number for your vinyl material yet?
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Old July 30th, 2004, 10:33 AM   #1149
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Vinyl

Brett,
To be honest, the vinyl is on a perfrated roll that's used for my cutter/plotter. There is no part number nor name. I'm going to go to the sign shop where I bought it (~$40/100ft) and try to find the same stuff. I should have a part number after that.

On another note, after a few days of finalizing my rod system, I got everything put back together so I could do some more testing with the vinyl. It appears it wasn't just a dream, the stuff really works well. To be honest, I couldn't ask for anything better. I can't even tell the difference when the adapter is on compared to when it's off other than the ~1 stop loss. I'd like to get the size down by going to an oscillator and would like to get the image errected, but hey, other than those issues that only affect me as the photographer, the image couldn't be better.

I'll get some stuff posted this weekend.

J
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Old July 30th, 2004, 12:35 PM   #1150
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Incredible! Only one stop loss? Are you sure? Check it with auto exposure and a full framed shot of a gray card for both with and without adapter to find out for sure.
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Old August 4th, 2004, 01:49 PM   #1151
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Wich side of the disk should point to the camcorder? The blank or frosty?

Why do flicker occur? It goes away with 3V-power.. but why is it really there at 1.5V?
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Old August 4th, 2004, 09:32 PM   #1152
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My experience has been that flicker occurs due to subtle differences in the texture of the groundglass finish around the disk which causes local areas of varying density. This affects the amount of light passing through.

I think the camcorder automatic exposure might also try to chase the light level and maybe aggravates it because under certain lighting/contrast conditions it becomes more apparent-(Last two words are later amendment to message).

At faster disk speeds the camcorder may be just going with the flow.

The disk defect is nearly impossible to see by eye and harder to control when making a plastic disk. An oily fingerprint on the groundglass surface is enough to make it happen.

3 volts seems to make it go away with the plastic disks. I couldn't control it at all with the wax composite disk and I gave up on that although it gave the sharpest images.

My personal preference is to have the groundglass surface closest to the camcorder so the camcorder sees the projected image without going through a layer of glass or plastic. It may not be the correct method.
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Old August 29th, 2004, 04:17 AM   #1153
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definitely interested in the vinyl, good work James!
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Old August 30th, 2004, 03:12 AM   #1154
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I'm also really interested in the no-name vinyl. Do you think the grain structure would work if it was laminated to an oscillating piece of glass?

James, what type of CD are you currently using to be a backer to the vinyl? If you're unable to find a part number, I'd also be interested in buying a couple sheets from you. I'm currently working on a spinning CD version, but am REALLY interested in getting an oscillating version up and running.

Brett, have you made any further progress with your oscillating design? I haven't kept up with the forums lately, and reading yours and Rais posts from the beginning of July has gotten me motivated to see what I can piece together.

(Found the post dealing with the oscillating design, sorry for the question before I searched the forums :P)
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Old September 2nd, 2004, 02:15 AM   #1155
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I am not sure if this would help anybody or not. I just started reading about the 35mm adapters and have been very interested in this topic.

Anyways I had a thought the other day about solving the inverted image problem. Since we are sort of using the lens from our old 35mm cameras how about somebody rip their camera apart and steal the mirrors, and prisms. Clearly everything is right there in the camera that we need. If nobody wants to rip apart their camera then maybe somebody can find a broke camera and try it. If we use the same system that is in our current 35mm cameras then the image will be corrected when captured by the video camera. This may also solve our ground glass problem since we wouldn't need it. Instead of projecting the image on a ground glass the image would be reflected by smooth mirrors. It would be like having your video camera shoot the viewfinder of your 35mm camera. No distortion, light problems, inverted images, or grain. I don't know if any of this would work but I never heard anybody really talk about this.
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