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Old April 4th, 2005, 08:26 PM   #46
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Oops I should have explained better. I was meaning the WD40 for the cutting wheel for the glass cutter. I was actually thinking of testing glycerine in the front prism maybe. Some people on that other site said it worked for them. I found a place locally that has it for like 20 bucks for a whole gallon. I might try that eventually.

I confused about the wider angles. Do you mean that each prism itselves would be a 40? degree prisms instead of 30 degree prisms? I was thinking backwards then that a smaller angle within the prism itself would make it wider, but that would make sense then because if it was 0 degrees (parallel) then it wouldn't widen it at all.
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Old April 5th, 2005, 06:44 AM   #47
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Hmmm...confusing isn't it. When you say 'wider view' do you mean a higher compression? It would mean the prisms themselves have to be build in a wider angle, so thicker and heavier. Like you said, if you have 0, parallel, the compression will be nothing of course. i.e. a narrow view.

LEt us know how the glycerine works out. I think if this gives more color aberration you have to put the rear lens in a wider angle in relation to the front lens to fix the aberration, this will give more compression, which is good. But I'm not sure about that, that's why I used water in both lenses.

EDIT:
I'm now working on one of those harmonica type sunshades to fit the lens. Anyone ever made these before?
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Old April 5th, 2005, 01:10 PM   #48
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D*MN Belt Sander

Well just after I posted those pics of my prisms, i took the glass out to my garage and started cleaning up the edges with my belt sander. I am in the process of building new work benches in my garage so teh sander was just put on top of a board and that was on top of the frame for one of the work benches.

Long story short, I was paying too much attention to the piece I was sanding and didn't notice the vibration the sander was causing. Next thing I know the rest of the prism pieces went crashing to the floor.

I was down to the 1 peice I was holding in my hand at the time. I had enough glass to cut a few new pieces, but I have to get more glass today to replace all of them.

Basically in 5 minutes time I took myself all the way back to square one.
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Old April 5th, 2005, 02:01 PM   #49
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Keith, I forgot to mention one thing about glass....

Maybe you got me wrong, because I didn't sand the glass, only the plastic sides, although it may not be a too bad idea, but only for the final version.
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Old April 5th, 2005, 03:05 PM   #50
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No, i got what you ment about the sanding on the plastic sides. I was cleaning up the edges on the glass because a few of them didn't break very cleanly so I was just running them across the belt sander to straighten out the sides to make it easier to seal. That's when they all fell.

Anway got more glass today so I'm gonna try and remake the prisms, already got a few pieces cut now. I have some quick set epoxy stuff that sets in minutes might try for the prisms. Might try to seal them today since it's nice weather here for once.
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Old April 5th, 2005, 03:52 PM   #51
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Good news Keith.

And now, for something completely stupid:

-These designs, tests ( and the result of them ) may not be used without the permission of Oscar Spierenburg.-

Aargh, I didn't like to do that, but because of the Panamorph thing on Aaron Shaw's thread, I want to ensure no company uses my tests for their profit. I put it on the pics as well.

Keith, you started without my permission. Go on..go on...
Oh..maybe you use a bit too thick glass? It doesn't matter for the lens, but it's harder to cut clean.
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Old April 6th, 2005, 07:10 PM   #52
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Here is a pic of how easily the lenses are supported even with this too big telephoto lens. They are really not that heavy.

Top view:
http://doublecam.250free.com/telephoto.jpg


or:

http://doublecam.250free.com
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Old April 10th, 2005, 10:43 PM   #53
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That prism is looking great Oscar, I think you have the leg up on alot of people here - two solid ideas that you have brought down to the consumer level - the doublecam and the anamorphic prism. Great work!
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Old April 11th, 2005, 07:31 PM   #54
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Thanks Leo.
I just had a thought, Keith and anyone who'll give a try on this lens should consider making it a rear version if there is some space left between the GG (of a 35mm adapter) and the DV camera. I noticed that a water prism has far less color aberration if it is put very close to an object. So if one would put it right after the GG, maybe you don't need a second water prism.
I can't try this easily on my adapter, but it's worth some testing.

By the way, I had some long test shooting with my double cam system and the anamorphic lens last weekend and everything worked just fine. I had the best results with a 135mm lens on the adapter.
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Old April 11th, 2005, 07:38 PM   #55
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I guess the only problem with 135mm is that you really need to be far away from the object or action for the Long shots - but that is an interesting observation.

Oscar, check you email, I sent you a vid clip.
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Old April 11th, 2005, 07:48 PM   #56
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That sounds like an interesting idea Oscar. I will give it a try once i get the prisms done. The part I don't understand is, don't you need both the prisms to squeeze the image fully to 16:9? I know the second prism corrects the colors and what not, but doesn't it also compress the image more?

I'm about 2/3 done with my rear prism now. I have the sides and bottom done and sealed enough to fill to test and the front prism is about 1/2 done. It has the sides and bottom together. I just have to finish sealing it tonight then wait till the silicone cures so i can test fill it. As long as there are no leaks I should be able to at least test it and see what kind of squeeze I am getting.

Oh forgot to mention I am trying a different angle in the prisms to see what kinda squeeze I can get it with it. Oscar once I can calculate the squeeze these produce then we should be pretty simple to figure out what angle prisms we would need to do 2.35 to 1.
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Old April 11th, 2005, 08:06 PM   #57
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Yes, the second lens is also to squeeze the image to the opposite side, but a prism close to an object seems to behave very differently. For instance, you have to rotate it 90 deg. otherwise it'll stretch the image horizontally. I'll try to test this myself on the end of the week.
Keith, great you are making you're lens in a different angle, I'm very interested in the results. I'll find a way to calculate the exact squeeze factor of my lenses.
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Old April 13th, 2005, 06:37 AM   #58
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Keith, I came up with yet another variation...If things will not work out with a 2.35:1 aspect ratio using the front prisms, maybe it will when a third lens is put between the GG and DV camera to further compress the 16:9 footage to 2.45:1.
Just a thought.
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Old April 13th, 2005, 11:29 AM   #59
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Confused

Okay I think I'm confused about something. I finally got a set of prisms put together with the sides and bottom (enough to fill and play with). I was under the impression to get a bigger squeeze in teh image the angle of the prism itself should be a larger angle. Was I thinking backwards?

The ones I finished last night didn't seem to compress the image at all, but maybe I just need to play around with them more? The only way I could get it to squeeze the image was if I pointed the 'points' of teh prisms back towards the camera lens... instead of away at 7 degrees and 9 degrees like yours is set up. Do you think I have to make the angle of the prisms smaller?
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Old April 13th, 2005, 03:05 PM   #60
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Now I'm confused too...I'm sure it has to be like you say, bigger compression with bigger lenses. It would really help if you post a picture of your setup. If possible put the camera in place to show how everything is positioned.
What angles are the prisms? Did you fill them with glycerine or water?


EDIT! The setup I posted is from TOP view, otherwise it'll have opposite effect.
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