DIY anamorphic lens

[fisher]

My (limited) research (surfing the web) indicates that crystal has a similar refractive index to flint glass (depending on the lead oxide content) and is used as a lens material.

I'm very tempted to order some myself but will hold off while I finish my resin prisms (I want to have a reference).

Please let me know what you think when they arrive.

BTW, did you see the glass lens' developed at the French site http://www.commandes-groupees.fr/viewtopic.php?t=109 (skhattane from post 478 this thread)? They grouped together to have a pair of custom prisms made from BK7 for 76 euros. Thats for the pair with MRC coating!

I PM'd him and he replied to my first email but nothing since.

[Mark Techer]

My (limited) research (surfing the web) indicates that crystal has a similar refractive index to flint glass (depending on the lead oxide content) and is used as a lens material.

Your searching skills are clearly better then mine I spoke to Foghorn 17 this morning and his concern was also the lead content...I had not really given it much thought, but still feel that so long as they are clear, they will work. It wil be interesting...

I'm very tempted to order some myself but will hold off while I finish my resin prisms (I want to have a reference).

Please let me know what you think when they arrive.

I will use my water prisms as a reference. The best resin prism I have ever made came close, but did not surpass the level that I have at this time, so I am chomping at the bit...And don't worry, as soon as they arrive, I will begin testing and documenting their performance and will post here...

BTW, did you see the glass lens' developed at the French site http://www.commandes-groupees.fr/viewtopic.php?t=109 (skhattane from post 478 this thread)? They grouped together to have a pair of custom prisms made from BK7 for 76 euros. Thats for the pair with MRC coating!

Yeah I did, but I didn't really follow the thread as I don't speak French, and the bablefish translator didn't do the best job. I got a bit of laugh when I read the translation about my screen shots - I am the guy that posted the photo of "the desctructables"...

I PM'd him and he replied to my first email but nothing since.

Yeah same here...

Mark

[Steve Scherrer]

I called one of the companies that sells these for $36 engraved, and when I told her I just wanted blanks, she referred me to the production company, which is a company called "Glass Graphics" in New Hampshire (I believe). The website is www.glassgraphics.com . When I called Glass Graphics, they told me they couldn't sell to me because I wasn't a distributor, and they didn't sell to individuals. So I would have to go back to the distributor--but she did mention a couple of distributors close to my house. (There were two in the next town over from me!)

I will try to give them a call today. However, the prices on these things seem to be anywhere from $36US to $150US, depending on the site selling. I am sure that Glass Graphics sells them for far cheaper than that. Maybe I'll set up a corporation just to source these things from Glass Graphics!

Anyway, I did call back the one distributor, and she hasn't called me back yet (for only two wedges, she probably doesn't want to be bothered). But the previous distributor I had called was very friendly--they were just out of stock. She said they could probably get them in a week or so. But she said I had to be careful--because they made these optic wedges for mainly two groups as trophies--the "Elks" and the "Rotary Club", and they pre-print the symbols on them as soon as they come in. If someone orders one from anybody, you have to make sure you can get them as "blanks".

If the local distributors don't come through, I'll probably go back to her. She was very curious why I needed them, and I explained the concept to her--she was very intrigued (and I got her to laugh when I said, "You see, there are a bunch of nerds on the internet (myself included) that are trying to make these lenses..." (No offense! )

Anyway--happy hunting--glad I could help this venture out.

[Steve Scherrer]

UPDATE: Just got off the phone from the distributor in Ohio, and she is having shipped to me directly from Glass Graphics a small wedge (J24) and a medium wedge (J25), and she quote me at $29.40US for the small one, and $39.20 for the medium one. (I didn't ask about the large one, but it is probably $10 more than the medium one).

I have to pay shipping, but it will probably be somewhere around $5US or so. So I will have these within the next couple of days. She was delightful to deal with, and apologized that she didn't know that Glass Graphics didn't deal with people off the street like myself.

Her company is called The Massilon Plaque Company our of Akron, Ohio. Their website for the optic wedges are: http://www.massillonplaque.com/produ...4&productid=85

[Mark Techer]

Awesome Steve

My prisms arrive here next week. I've got two of the larger size 170m x 140mm coming. (see Fisher's post about 8 back) I also have anti-reflection glass (for the front).

I was also asked what I wanted engraved, and the lady was a little surprized when I said nothing, I want them blank...

Mark

[Mark Techer]

And here they are

Screen shots coming soon...

Mark

[Mark Techer]

And as promised - screen shots...






Its good compare same frame taken earlier to see just how much better these new prisms are...

Mark

[sdspga]

Mark,

You've got to be kidding me! Those images look fantastic! I assume once you have the prisms in the beam that you just adjust them to the proper angle to produce the properly focused picture??

How are these with the usual problems of CA, Barrel and Pincushioning? Is two the magic number, or will you try four? Thanks for the pics.

Scott

[Foghorn17]

Great job Mark.

The shape of the R2 Unit in that screen shot looks perfect. I know that screen shots never look great, but it sure looks like these prisms provide good geometry and minimal loss of focus.

The future looks very bright for the Aussiemorphic Lens

[Mark Techer]

Originally posted by sdspga
[B]Mark,

You've got to be kidding me! Those images look fantastic! I assume once you have the prisms in the beam that you just adjust them to the proper angle to produce the properly focused picture??

Don’t want to blowing my own horn here, but I didn't place them in the beam first at all. I have been doing this for over a year now, so basically knew a rough angle they would need to be in relation to one another, and it appears that I got it right too . I simply loaded the m into the case, tightened down the lid, and them fired up the projector, and I was totally blown away when it worked

The beauty of prisms is that they don't (or shouldn't need focusing if they are manufactured correctly. Unlike the elements of a cylindrical lens, the spacing between the prisms can vary considerably, where the ends of my prisms actually touch. If you read the results of a few (one took to a 2x with a hacksaw) who have done this, you read about how the spacing between the elements is crucial to the success, but it does not appear to be the case with the prisms. The only limiting factor is if they are too far apart, the lens would vignette…

I've worked out the design so that when the prisms are set in the MDF case, they are in the right position, but today had to be a bit of fluke but one that worked out really good...

How are these with the usual problems of CA, Barrel and Pincushioning? Is two the magic number, or will you try four? Thanks for the pics.

Your very welcome

2 works really well, but I think 4 will be even better and I will order a second set soon enough.

As for CA, you can see a bit on the first screen shot on the back of her neck (faint blue line) if you look for it. I've watched 3 films now, and am totally blown away with the clarity of the image (good find Fisher and Steve ) which is way better than the water prisms could ever hope to be...

The Barrel and Pincushion is no where as bad as the water prisms either. With my extremely short throw projector, any image distortions are going to be worse due to the nature of the sharper angles to bend the light, so as you can see, there is not too much issue with the images at all, so a long throw projector would be awesome...

Originally posted by Foghorn17
Great job Mark.

The shape of the R2 Unit in that screen shot looks perfect. I know that screen shots never look great, but it sure looks like these prisms provide good geometry and minimal loss of focus.

The future looks very bright for the Aussiemorphic Lens

Thank you Foghorn for keeping the faith

The focus remains quite sharp across the image with a very slight softening starting about a foot in at the edges. But unlike the water prisms, I can clearly see the scan lines all the way to the edges…The horizontal pixels are not as visible due to the fact that this is a HE lens…

The geometry is a real trip, as I could never get such a perfect symmetrical stretch with water prisms. Tonight I watched an older film WATER WORLD (not even 235) and used the 4 x 3 + lens to make the 16:9 image. The MCA Universal logo at the beginning was perfect, where the water prisms always seemed to be a little off on one side…

Something to watch for – 235 films are not true 235. There is some over scan, and some (a lot) has to do with my projector, but the truth is 16 / 9 x 1.33 = 2.37, not 235, and even building the screen out to 239 would be preferred.

I am building another screen soon, and will simply side mask the ends, not hard edge with a frame like I have…

Can’t wait till those that ordered a set of these prisms have their lenses up and running and we can compare findings. This is getting exciting once again…

I didn’t use the antireflection glass either BTW, but place 2” wide duct tape over the fat ends of each prism. This prevents a lot of the stray light that has caused previous lens makers so much grief with reflections on the screen and other walls etc…

Mark