View Full Version : Water and oil anamorphic prisms


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Oscar Spierenburg
April 5th, 2005, 02:52 PM
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.

Oscar Spierenburg
April 6th, 2005, 06:10 PM
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

Leo Mandy
April 10th, 2005, 09:43 PM
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!

Oscar Spierenburg
April 11th, 2005, 06:31 PM
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.

Leo Mandy
April 11th, 2005, 06:38 PM
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.

Keith Kline
April 11th, 2005, 06:48 PM
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.

Oscar Spierenburg
April 11th, 2005, 07:06 PM
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.

Oscar Spierenburg
April 13th, 2005, 05:37 AM
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.

Keith Kline
April 13th, 2005, 10:29 AM
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?

Oscar Spierenburg
April 13th, 2005, 02:05 PM
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.

Keith Kline
April 13th, 2005, 06:56 PM
I'll post some pics tonight of the way I had it set up. I also have a new rear prism about 1/2 done with a different angle in the prism.

With the larger angle prism it would only work with the prism points facing towards the front of the camera. I'll post some pics tonight so you can see what I was saying.

Keith Kline
April 13th, 2005, 09:27 PM
Bottom of the page...

http://www.twistedinsomniac.com/mini35/

Oscar Spierenburg
April 14th, 2005, 04:35 AM
I checked my prisms, but just by looking through them does not make you think it's stretching that much, so are you sure the first setup is doing nothing? I just don't understand. Try looking at something square.


Also (I know it as just a quick test), but notice that there is color aberration in your picture so you have to place the prisms in a smaler angle (to each other and the camera lens) There is just one angle where the aberration is gone.

Leo Mandy
April 14th, 2005, 04:21 PM
Keith you are making awesome progress! Good for you, I would love to see more. How did you come up with the Wax technique?

Keith Kline
April 14th, 2005, 05:06 PM
<<<-- Originally posted by Mandy Leo : Keith you are making awesome progress! Good for you, I would love to see more. How did you come up with the Wax technique? -->>>

Thanks. It's getting there. I based the wax glass on the ideas I got from this thread...

http://www.dvinfo.net/conf/showthread.php?s=&threadid=33489

It's slowly but surely getting there.

Keith Kline
April 14th, 2005, 05:08 PM
Oscar:

I have the rear prism done using a smaller angle and the front is about 1/4 done. I should be able to test these new ones tomorrow and see if that makes it worse or better. I'll let you know what i find out.

Leo Mandy
April 14th, 2005, 05:36 PM
I myself am waiting on a achromatic dioptre that I ordered off ebay without bidding - I just couldn't wait! When that comes in, I am going to finish up my DOF machien and onto the anamorphic prism, which I think is awesome! Great job both Oscar and Keith.
I am going to have to source out some cheap museum glass though...

Oscar Spierenburg
April 14th, 2005, 06:00 PM
For the glass, try a framer (as in: frames for paintings), they often have left over strips of museum glass.


I also want to let people know that my 16:9 prisms work perfectly, as I have shot some 30 minutes of footage without any trouble. The prisms are not too heavy, are not too vulnerable(I dropped one on the floor by accident and nothing happened) and in my setup they are easily positionable when changing lenses.
I can use 50mm and 135mm lenses with no problems.


On more thing, the museum glass deals with reflections perfectly, I had only one lens flare when I put the camera next to a 500w spot with totally uncovered lenses and no sunshades.

Keith Kline
April 14th, 2005, 06:34 PM
That's great to hear Oscar. I'm amking progress on my new front prism and I think I have enough materials to make a set with 30 degree prisms so that way we can compare the 3 sets to do any calculation we might need to do. Once I get a set looking close to what i want it to I'm going to contact some framing shops to see about getting some scrap pieces.

Also does anti reflective mean the same thing as anti glare?

Leo Mandy
April 14th, 2005, 06:42 PM
Footage Oscar, footage!!! I want to see it!

Oscar Spierenburg
April 14th, 2005, 06:46 PM
Let me edit it a bit and I'll post some....tomorrow, it's too late at night at my half of the globe right now.

Leo Mandy
April 14th, 2005, 07:20 PM
I'm looking forward to it.

Leo Mandy
April 16th, 2005, 04:59 PM
Hey Oscar,

I am having a bit of a time finding 'museum' glass. Two places today never heard of it, but another place - after I explained - showed me non-glare glass, the problem was it was slightly frosted. Is there another name for it?

Oscar Spierenburg
April 16th, 2005, 07:25 PM
It's also called anti-reflective glass and sometimes UV-glass, but than you have to be sure it has an anti-reflective coating too.
The non-glare glass is unusable. Like you said, it's frosted (like a pretty good ground glass actually.)

Take a look at http://www.tru-vue.com/Content.asp?pn=consumer/products
Thats the kind of glass you need.


OK, here's just a portion of the test scene I did last week, to show a small pan with the anamorphic lens (and a 135mm lens on the adapter) click on the top link on my page:
http://doublecam.250free.com/
The dark spots on the top left got nothing to do with the lenses, it's dust on the mirror of my double camera system.

Jonathan Pacheco
May 16th, 2005, 07:19 PM
Any more news? After seeing that footage, I was amped!

Oscar Spierenburg
May 17th, 2005, 05:02 AM
Thanks.
I didn't really post a full frame of that test on this thread, so here it is:
http://doublecam.250free.com/135mm.jpg

I am working on some other things, but I'll come back to the lenses soon (more to finish it, because they work fine)
I was hoping Keith Kline would get some results in different compression, but he seems to be gone from the board for a wile now.

I'm still thinking about a new setup with the big lens in front of the 35mm adapter and the small lens beween the GG and the DV camcorder. It'll save much space and get more view so you can use a wide angle lens, but I don't know if the color aberration will be corrected the same way.

Note that the lenses also work on a DV camcorder without a 35mm adapter.

Keith Kline
June 3rd, 2005, 10:53 AM
Okay I just posted in the micro wax thread too so I'll save the story, but I'm back. I'm gonna try to get some time to start some new prisms this weekend. Not sure what causes the difference in the prism layout, but a smaller angle was not the way to go. I tried a pair at 20 degrees and it didn't do anything. I think I'm going to do a 30 degree set and follow yours so that way we have a reference and a way to compare the compression changes. I'm also going to make a 35 degree pair and see if that works better than my 40 degree pair.

Oscar Spierenburg
June 5th, 2005, 06:18 AM
Welkome back here too Keith. By the way, I'll go back into anamorphics myself, because I'm making a new adapter with a wax GG.
Maybe I'll just use the other prisms I made, but if it's possible, I'd like to make it a half rear, half front version to save space. I mean: One water prism in front of the adapter, so you can use wider lenses too. The other water prism should go right behind the GG (between the GG and DV camcorder)
The rear lens could be almost as small as the 35mm image.

Also, 2.35:1 if possible.

Oscar Spierenburg
June 5th, 2005, 07:03 AM
Double post.

Jonathan Pacheco
June 5th, 2005, 08:06 AM
Woo hoo! Back again :)

Oscar Spierenburg
June 26th, 2005, 06:50 AM
I am working on my new (static) adapter with the micro wax, so I'm reconsidering the anamorphic plans. I found out something interesting.
You need two water prisms to correct the color aberration. I don't know how it works, but I remember reading somewhere it has to do with the different speeds of the colors of light. So I was thinking, the closer the image to the lens, the less aberration it should have.
It turns out to be true, if you put one water prism very close the an image (like a GG) you don't see any aberration.

With this new idea, I'll start doing some tests this week. It would make everything much easier and smaller, because you'd only need one prism between the GG and the camcorder.

Leo Mandy
June 26th, 2005, 08:04 AM
Do you have enough room to put it between the GG and the DV camera - is that what you meant? I wonder how they manage to do it on film where they put it in front and do not have the colour problems there?

Oscar Spierenburg
June 26th, 2005, 08:19 AM
It's not so big, so there should be enough room to put it. I made a front one just like the old ones for movie camera's, the aberration is gone with a second lens, but that makes the thing pretty big( and they were very big on movie cameras http://www.widescreenmuseum.com/widescreen/camera65_evamarie.jpg).

Leo Mandy
June 26th, 2005, 08:42 AM
Try putting that on a Steadicam! Ouch, Garret Brown!