Yeah that makes sense with the distilled water. I just picked up some cheap window glass for a prototype and a glass cutter today. I'm gonna start working on some stuff tonight. What did you use for the tops and 3rd side? I noticed you pliers in the one pic, are those the type to actually work with glass or are they regular pliers? The place I went didn't have the type for glass working.

Eventually once i get an okay version of the 16:9, i'd like to try and 2.35:1 ratio. Do you think to get a wider image you could just decrease the angles on the prisms? Say to like 20 or 25 degrees (instead of 30 degrees)maybe?

Also you said that the 28mm lens was too wide. How much larger do you think the adapter would ahev to be to fit that sized lens? I mean would it have to be twice the size? less?

Okay that's enough questions.

Oops
 

Sorry 1 more question. When you unsqueeze the footage, are you just doing it by eye or are you using some way to make sure you're desqueezing enough or too much?

Keith,
I made the other pieces from the clear side of CD jewel cases, grind it with sand paper to lose the reflection and paint it black on the outside when everything is finished.I always glue everything with (a lot of) 30min epoxy and when I'm not sure it's waterproof I put some kind of black roof adhesive on it.

To test the sizes the lenses should have, try holding some cardboard in front of the lens and note when it gets in and out of view. The farthest point will be about 10 cm from the front of the lens. I'll test this on my 28mm lens too, because I don't know.
If you make thicker lenses (more than 30°) and we compare compressions, we might come up with a calculation of the compression.


I'm not sure which pic you mean, but they must be regular pliers. I break the glass on the ruler itself (put the cutting line on the edge of the ruler after you cut it, and break it by pressing it with your hands. Also, don't push too hard when cutting and use some white spirit on the cutter.)


On one test I unsqueezed the footage on top af a shot without the lens, so I could check exactly what it should be.
Hope it works out for you, let me know!

Step 1
 

Okay got the stuff set up on my work bench and cut out some pieces of glass. I need to figure out what to use as oil. I wonder if something like WD-40 would work or if you should use something special.

I based my calculations on your prisms Oscar. I just enlarged the size slightly. I think it's only about 25% larger maybe. I figured I'd try to see if I could make it fit a wider lens.

I'm also going to cut another set possible once I see how this works to test alternative angles to try for 2.35:1 or something close. 2 questions about that... 1 to make the view wider the angle of the prisms should be smaller (20-25 degrees maybe) or am I thinking wrong? Also do you think I should make the panels longer side to side to account for the wider view? I mean the angles are the most important part correct? Even if I made the sides longer it woudn't hurt anything would it?

There are some pics of my progress so far at the bottom of the page posted below if you want to check them out.

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

Perfect! I had the exact same thing set up a week ago.(my grand piano was the work bench though)

The best, most quick way to seal it is definitely epoxy glue. Tape or hot-glue will be leaking in a few seconds. I put the top (non-angled) plastic part last and flushed the triangle box just before that. This part has to have a small hole on the highest corner to give the smallest bubble of air as possible when filled with water.

I didn't use oil, but water for both. If you want to use oil (for the front lens) maybe WD40 is too aggressive, I used some sort of cheap furniture mineral oil for a test lens.

About the angles, to give higher compression the lenses have to have a bigger angle, like 40 degrees. I mean the lenses themselves.

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.

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?

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.

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.

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.

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.

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

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!

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.

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.

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.

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.

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.

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?

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.

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.

Oscar
 

Bottom of the page...

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

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.

Keith you are making awesome progress! Good for you, I would love to see more. How did you come up with the Wax technique?

<<<-- 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/showthrea...threadid=33489

It's slowly but surely getting there.

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.

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...

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.

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?

Footage Oscar, footage!!! I want to see it!

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.

I'm looking forward to it.

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?

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.

Any more news? After seeing that footage, I was amped!

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.

I'm Back
 

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.

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.

Double post.

Woo hoo! Back again :)