or Connect
AVS › AVS Forum › Display Devices › 2.35:1 Constant Image Height Chat › DIY Constant Height › DIY Cylindrical Anamorphic lens
New Posts  All Forums:Forum Nav:

DIY Cylindrical Anamorphic lens

post #1 of 28
Thread Starter 
Has anyone tried making a cylindrical anamorphic lens? I was thinking of starting with a cylindrical lens for horizontal expansion. I would imagine the most difficult part about it would be getting it to focus evenly across the screen. Still, though, there should be additional lenses that could be added to focus on the same plane while maintaining the expansion. Anybody try this?
post #2 of 28
Interested. How are you working out focal lengths etc?

Mark
post #3 of 28
Thread Starter 
Actually, I noticed that the Panamorph website already has the theoretical information on cylindrical anamorphic lens.

http://www.panamorph.com/Technology.html

As for the focal lengths, I first have to back and brush on my optics; however, it shouldn't be impossible to determine. I think it has promise. Per the article, the astigmatism will be hardest to correct, and I would imagine that the degree to which we can match the curvature of the cylindrical lens to the correcting lens will determine how much astigmatism there will be.
post #4 of 28
Best for you to start liquid filled prisms
post #5 of 28
Thread Starter 
Well, recently I've been thinking it might be worth a try to use mirrors. The big problem with that is that the mirrors have to be big because the light coming from the projector is fast, but they don't have to be if you use a concave mirror to focus and "slow" down the light beam.
post #6 of 28
Light speed is not constant? Are you talking about light traveling in different solid or liquid?
post #7 of 28
Thread Starter 
No, in this sense "speed" doesn't mean the speed of light. Instead, it just means that a beam expands quickly--e.g. a short throw in a projector where the image gets big in a shorter distance than in a long throw projector. Nothing to do with the actual speed of light.

If you have a beam of light that expands quickly then each mirror that you bounce it off will have be bigger than the next. What I meant by "slowing" it down was simply change the beam from quickly expanding to not expanding, then stretch the image, then have it expand at the original rate.
post #8 of 28
Quote:
Originally Posted by prabhatb View Post

Best for you to start liquid filled prisms

Now why would you even suggest that when solid BK7 prisms are available.

Quote:
Originally Posted by Fabbas View Post

Well, recently I've been thinking it might be worth a try to use mirrors. The big problem with that is that the mirrors have to be big because the light coming from the projector is fast, but they don't have to be if you use a concave mirror to focus and "slow" down the light beam.

Not to rain on your parade, but there was a long and argumentative thread in the main section about this. End result - it does not work...

Mark
post #9 of 28
I was poking fun at this thread. How practical it is?

As practical as: Hey, how about creating a DIY DMD device with full RGB colored mirror arreay in a 2.35 aspect ratio. Then build a projector around it. Any ideas?
post #10 of 28
Thread Starter 
Quote:
Originally Posted by CAVX View Post

Now why would you even suggest that when solid BK7 prisms are available.



Not to rain on your parade, but there was a long and argumentative thread in the main section about this. End result - it does not work...

Mark

Thanks, Mark. It took me a while to find it, but I'm going through it now. So far there's one key point that's been left out, but I'll continue looking through it and post there.
post #11 of 28
Quote:
Originally Posted by prabhatb View Post

I was poking fun at this thread. How practical it is?

How practical is what? To build a cylindrical anamorphic lens? It can be done, but prisms versions are just allot easier...

Mark
post #12 of 28
Quote:
Originally Posted by CAVX View Post

How practical is what? To build a cylindrical anamorphic lens? It can be done, but prisms versions are just allot easier...

Mark

I did not say it cannot be done. (just as Napoleon would say) !
But it is going to be so difficult than prisms that it would amount to non-practical for us common folks.
post #13 of 28
Getting the lenses made is the thing. Prisms allow use of an off-the-shelf item.

Corning may even have what is required as a "stock" item, if they're purchased in enough quantity.

C
post #14 of 28
Nothing I have found as a "stock item" is large enough...

Mark
post #15 of 28
Mark, the next level DIY project should be non-ca prism lens. I know you have started looking in to it. How difficult it is to get a ca-canceling prism to be paired up with BK7 prism? What could be their spec? (e.g they have to be different refractive index and what are they)
post #16 of 28
Quote:
Originally Posted by prabhatb View Post

Mark, the next level DIY project should be non-ca prism lens. I know you have started looking in to it. How difficult it is to get a ca-canceling prism to be paired up with BK7 prism? What could be their spec? (e.g they have to be different refractive index and what are they)

I have done the research and CA correction is a two step process -
1. Find the material with the correct refractive index (done).
2. Bond the prisms together so that there is no air/surface interfacing between the two materials. (found a glazier that can do the job at reasonable rates.)

Problem is, I have to order a minimum of 500 units...

Mark
post #17 of 28
Have you actually tested this Mark ? ... or is it still theoretical ?

If it is proven tested by you I am sure you can go to the original purchasers of the Aussiemorphic and see if you can get some preorders in place to offset the cost
post #18 of 28
Quote:
Originally Posted by Justletmein View Post

Have you actually tested this Mark ? ... or is it still theoretical ?

If it is proven tested by you I am sure you can go to the original purchasers of the Aussiemorphic and see if you can get some preorders in place to offset the cost

My understanding is that this other glass type is way more expensive than BK7 (which is why it is not widely used).

I have not been able to "test" this as the prisms manufactures want me to purchase enough material to make 500 prisms. They won't buy the material unless they know that I will buy it all off them so they won't be stuck with stock they can not use or sell.

The computer simulation (where the only variable changed was the RI of the glass type) proved the results.

Don't forget, you still need them bonded as well...

Mark
post #19 of 28
Mark,

Can this manufacture of yours not bond the prisms as required? I suppose if they can build the prisms they can bond them. I know you will find a way...

If you plan to get us this kind of lens without housing or anything around it (to keep the cost low), I will certainly pitch in, so count me in. 500 is a little big number, but I am sure most of the AVS members will be interested.
post #20 of 28
Quote:
Originally Posted by prabhatb View Post

Mark,

Can this manufacture of yours not bond the prisms as required? I suppose if they can build the prisms they can bond them. I know you will find a way...

Most of the manufactures I have dealt with seem to think that the surface area of glass is too big and will create bubbles, so either said they can't so it or wanted to charge ridiculous prices. A glazier I spoke to said they do full size windows, so a 140 x 170mm surface is nothing - just time consuming if anything and quoted a decent price.

Quote:


If you plan to get us this kind of lens without housing or anything around it (to keep the cost low), I will certainly pitch in, so count me in. 500 is a little big number, but I am sure most of the AVS members will be interested.

I'd like to offer the whole thing if possible including a injection moulded plastic case, but it all depends on numbers at the end of the day. I see huge market potential for this in the next few years, but I need to also see sales figures if I am to go ahead with this project...

Mark
post #21 of 28
Greetings folks,
I'm a newby to this thread and forum - just got into home theater with a Panny AE2000 so it has really peaked my interest in anamorphic solutions. I mentioned on another thread that the professional anamorphic prism systems use two achromatic prisms. These are the $10k + anamorphic adapters. I believe a slab of flint and crown are cemented together to achieve this. Look through a single prism, very little color dispersion will be seen as opposed to a single prism. I'm familiar with cementing lenses and for flat surfaces, this is no biggie using optical cement. The problem is in the main design. The optical indices of both glass components must be well known and that determines the wedge angle of each. Of course, you're dealing with two different pieces of glass now, and that increases cost significantly. You also need to have the cemented assembly coated for best results. I don't want to discourage anyone - just give those ambitious enough some extra information to go on so I can get the materials in a few months when you figure all this out and post it

On another slightly different topic. Cylindrical lenses work well - I just tried a test setup using opthalmic test lenses (available as cylindrical lenses from Premiere Products in Seattle), and it works good for the design purpose. I used a negative 6.0 diopter and a positive 4.5 diopter cylindrical lens pair (ratio of focal lengths is close to 1.33). The only problems are that these are simple 1 inch aperture lenses and not achromatic so they couldn't be used for a typical projector beam, but scaled up and corrected for color would probably work well (I already checked - none of the lens companies out there, that I could find, have anything available although there are some Chinese optical companies willing to make anything - so their web as says - I didn't explore that).

This might give somebody something to think about.
Bob D
post #22 of 28
It is possible to build DIY cylindrical liquid lenses. At least it has been done for holography. There is a great book on holography by Graham Saxby. When I did a google search, I got the following link that previewed the relevant chapter of his book. http://books.google.com/books?id=_o3...PRA17-PA224,M1
post #23 of 28
RBTO,

Great post, thanks PM sent...

Toups,

I don't see making a liquid version any different when I made liquid filled prisms excpet that now you need to calculate the radius for the two elements and that DIY would too hit and miss...

Mark
post #24 of 28
The needed equations can be found on page 228 of the book. From the link I posted I was able to get there, but some pages before were not displayed.
post #25 of 28
Awesome find, thank Toups...

Mark
post #26 of 28
yep, that's it, I'm done clicking on links in this forum....they just make me feel stupid Hope you guys can figure it out
post #27 of 28
Hey Mark, I was wondering, why haven't you made a jump to a cylindrical design yet? I thought the MKIII would've surley been it :-)
post #28 of 28
Quote:
Originally Posted by speedtriplex View Post

Hey Mark, I was wondering, why haven't you made a jump to a cylindrical design yet? I thought the MKIII would've surley been it :-)

Mainly cost, but there are a few other issues as well that I do not wish to openly discuss at this time...

Mark
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: DIY Constant Height
AVS › AVS Forum › Display Devices › 2.35:1 Constant Image Height Chat › DIY Constant Height › DIY Cylindrical Anamorphic lens