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.
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.
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 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...
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"...
Yeah same here...
Mark
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.
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.
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/product-detail.php?templateid=4&productid=85
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/product-detail.php?templateid=4&productid=85
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
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
And as promised - screen shots...
Its good compare same frame taken earlier to see just how much better these new prisms are...
Mark
Its good compare same frame taken earlier to see just how much better these new prisms are...
Mark
WOW!!!!
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
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
Who'dathought
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😎
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😎
Re: Who'dathought
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...
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...
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
sdspga said:
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...
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...
Thank you Foghorn for keeping the faith 🙂Foghorn17 said:
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
diy plans
does anyone have the plans, angles and where to get these new "trophy(lenses)". I own a ht company and want to try to make one for my own ht. The original post is not working. any help would be greatly appreciated.
does anyone have the plans, angles and where to get these new "trophy(lenses)". I own a ht company and want to try to make one for my own ht. The original post is not working. any help would be greatly appreciated.
I did a search online when looking for these wedges originally, and I found two trophy companies that can order them fairly cheaply, and the source company. I could not order from the source, because they don't sell to individuals, only to distributors--but if you have a HT company, you may be able to set up an account for them, and order them very cheaply. The source is:
http://www.glassgraphics.com/. Click on the catalog and scroll down a little bit on the left. YOu had to look hard, but the crystal wedges are there, about five images from the top.
So I went back to the one distributor that I had been in contact with, and they ordered it for me at cost, I believe (because they were blanks, and not etched in any way). The cost for the prisms were $29 for the small and $39 for the medium. The largest would probably be $49 (I forgot to ask, because I ordered a small and a medium).
The distributor I ordered from: http://www.massillonplaque.com/product-detail.php?templateid=4&productid=85
Another distributor that was very helpful: http://shop1.mailordercentral.com/aasc/prodinfo.asp?number=RR7216 (By the way, this distributor makes these trophies for the Elks and Rotary club, so if you order them, make sure they are true blanks, and don't have the elk or rotary symbol already etched. The woman told me that they order them at their company, and pre-etch the symbols on them and wait for orders for the remainder of the etching.
Mark: I am very glad your prisms have worked out the way they have. What are the chances you could line these up iwth a Prismasonic HE lens, and compare? I only have a panamorph VC lens, and I don't have a WVGA or WXGA projector, just SVGA. But as I said, when I get the lenses, I will be experimenting with going 2.35:1 from 1.33:1. I am excited to get these prisms. Stupid Labor Day holiday. I may get them tomorrow...
http://www.glassgraphics.com/. Click on the catalog and scroll down a little bit on the left. YOu had to look hard, but the crystal wedges are there, about five images from the top.
So I went back to the one distributor that I had been in contact with, and they ordered it for me at cost, I believe (because they were blanks, and not etched in any way). The cost for the prisms were $29 for the small and $39 for the medium. The largest would probably be $49 (I forgot to ask, because I ordered a small and a medium).
The distributor I ordered from: http://www.massillonplaque.com/product-detail.php?templateid=4&productid=85
Another distributor that was very helpful: http://shop1.mailordercentral.com/aasc/prodinfo.asp?number=RR7216 (By the way, this distributor makes these trophies for the Elks and Rotary club, so if you order them, make sure they are true blanks, and don't have the elk or rotary symbol already etched. The woman told me that they order them at their company, and pre-etch the symbols on them and wait for orders for the remainder of the etching.
Mark: I am very glad your prisms have worked out the way they have. What are the chances you could line these up iwth a Prismasonic HE lens, and compare? I only have a panamorph VC lens, and I don't have a WVGA or WXGA projector, just SVGA. But as I said, when I get the lenses, I will be experimenting with going 2.35:1 from 1.33:1. I am excited to get these prisms. Stupid Labor Day holiday. I may get them tomorrow...
Re: diy plans
PM me, I have a plan 🙂
I will contact a friend who has both a H600 and a H1200 and a very long throw 720 projector, fed by a HTPC through an out board scaler and will do a more comparitive test...
Mark
mookieo2 said:
PM me, I have a plan 🙂
Steve Scherrer said:
I will contact a friend who has both a H600 and a H1200 and a very long throw 720 projector, fed by a HTPC through an out board scaler and will do a more comparitive test...
Mark
Hi Mark,
Those screenshots look great. Well done.
I have been looking for, but unable to find) any real information about how well commercial lens perform, e.g. specifications for CA, distortion, light transmission or focus uniformity.
I will be very interested to see how well these crystal prisms preform compared to the H600 and H1200. I am also keen to see the difference between the two prismasonic lenses.
It will be hard to guage this with movie screenshots. As you will be using a HTPC would it be possible for you to use test patterns like the ones here (if you don't mind Sammy)?
http://www.homecinema-fr.com/forum/....php?t=29803723
Close up shots of the screen corners would be very telling.
Also, could you give us some indication of the prism geometry. How well does the crystal bend the light?
Greg
Those screenshots look great. Well done.
I have been looking for, but unable to find) any real information about how well commercial lens perform, e.g. specifications for CA, distortion, light transmission or focus uniformity.
I will be very interested to see how well these crystal prisms preform compared to the H600 and H1200. I am also keen to see the difference between the two prismasonic lenses.
It will be hard to guage this with movie screenshots. As you will be using a HTPC would it be possible for you to use test patterns like the ones here (if you don't mind Sammy)?
http://www.homecinema-fr.com/forum/....php?t=29803723
Close up shots of the screen corners would be very telling.
Also, could you give us some indication of the prism geometry. How well does the crystal bend the light?
Greg
fisher said:
Thanks, I am very impressed myself 🙂
And you won't because CA, Barrel/Pincushion and other optic distortions are bad, and the manufacture is going to be very reluctant to admit their product has a fault...
The interesting part of a prism based lens (from over the last year) is that the focus remains consistant regardless of the spacing. My understanding of how it works is due to the non parallel surfaces, which slow the speed of light. The result is CA...
So am I becuase so far as I can tell, they have the same clarity, so it will come down to the RI for each...
The last time I did a "shoot out" on this system, we used a combination of HD (1080P) source material and computor text (which is the most sensitive), so most likely, we will just repeat the same tests...
The Prismasonic H1200 won last time round 🙂, so given its price point, will be interesting to see how these prisms go...
Mark
Steve,
Wouldn't you need some kind of custom scaling to do this? I thought normally the preset scaling was for going 16:9 to 2:35 or 4:3 to 16:9. To go all the way from 4:3 to 2.35, wouldn't you need a little extra stretch?
sds
For those that want to know just how good these new prisms are -
Tonight after a quick re-cal, I removed the lens. I did not notice any brightness or colour increase - they are that transparent...
Mark
Tonight after a quick re-cal, I removed the lens. I did not notice any brightness or colour increase - they are that transparent...
Mark
sdspga said:
Yes, as Mark said, I will need vertical stretch. The problem is that there is no anamorphic 2.35:1, only 16:9 anamorphic stretch. The remaining image for 2.35:1 are black bars that are part of the image itself. So I would need a scaler to stretch the image further to eliminate the black bars (this is no different from any projector in this realm of using anamorphic lenses--however, most people have 16:9 projectors where the first step in the stretch, the anamorphic stretch, has already been done thereby filling the entire panel of the projector, and the scaler does the rest.
What I am doing is trying to use the entire panel of a 4:3 projector. In my case, I am using an SVGA projector, which is 800x600 pixels. My thought is that if I can vertically stretch the 2.35:1 image to fill the entire 600 pixel high panel, then I will be preserving much of the information of the image (especially for HD source material). I don't know if I get a benefit, necessarily from doing this with DVD source, except to significantly decrease the pixel size to eliminate the screen door effect. There shouldn't be any more information on the image, so if effect, by stretching it vertically, I am merely zooming the image out.)
But for HD source material, I should be adding information to the image during the vertical stretch--because instead of scaling down 1080i (540p?-but it would be less because of the black bars...) or 720p (same) to 480p, I am scaling to 600p--which is pretty darn close to HD material. That is my understanding, but perhaps I am wrong on this point.
Anyway, to make a long story short, I had looked into some external scalers, and they are very expensive. I played around in the service menu of my projector, and found that my 4:3 projector will do the remaining stretch. Of course, I am limited to the quality of the scaling of my projector (which is probably not very good), and I am sure one the external scalers could do a better job, but I am content to use the projector's scaler for proof of concept.
Crossing my fingers that my prisms come today.
Hi Steve,
Your benefit will be from using all of the vertical pixels of the projector's panel as opposed to 75%.
2.35:1 / 2 is 1.175 which equals 705 (roughly) pixels of the 800 that you will have, so there will be small portions of unused horizontal pixels when this is done.
Given that we are more sensitive to vertical rez than we are to horizontal, it will actually be better than the letterboxing you would have going 16:9.
Of course to do this, you will need a lens capable of at least 2x stretch...
I wonder just how far the prisms will stretch before they introduce problems?
Mark
Your benefit will be from using all of the vertical pixels of the projector's panel as opposed to 75%.
2.35:1 / 2 is 1.175 which equals 705 (roughly) pixels of the 800 that you will have, so there will be small portions of unused horizontal pixels when this is done.
Given that we are more sensitive to vertical rez than we are to horizontal, it will actually be better than the letterboxing you would have going 16:9.
Of course to do this, you will need a lens capable of at least 2x stretch...
I wonder just how far the prisms will stretch before they introduce problems?
Mark