Interesting results
I have been doing some experimenting with prism materials and wanted to share my results. I made the non optical portions of the lens out of double sided circuit board material that I simply soldered the ends to the bottom and painted flat black. Using mineral oil and distilled water. All 4 optical sides were constructed from lexan (slightly overlapping the sides and bottom) and adheared from the outside using E 6000 adhesive previously mentioned in prior posts. This stuff works well in sealing against leaks. I was unable to get a uniform focus across the screen whiich I attributed to the lexan. Replacing the water prism lexan with a thin picture frame glass focusing was no longer an issue. Not sure if anyone else had this problem?. At this point I am not totally convinced that the compressed screen image is superior to the same image without the lens. I have a 1024X768 DLP . I will replace the remaining lexan on the oil prism with glass and see if there is any improvement. Perhaps its just my building skills but was curious if any of you have seen a marked improvement in the image with your set up?
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I have been doing some experimenting with prism materials and wanted to share my results. I made the non optical portions of the lens out of double sided circuit board material that I simply soldered the ends to the bottom and painted flat black. Using mineral oil and distilled water. All 4 optical sides were constructed from lexan (slightly overlapping the sides and bottom) and adheared from the outside using E 6000 adhesive previously mentioned in prior posts. This stuff works well in sealing against leaks. I was unable to get a uniform focus across the screen whiich I attributed to the lexan. Replacing the water prism lexan with a thin picture frame glass focusing was no longer an issue. Not sure if anyone else had this problem?. At this point I am not totally convinced that the compressed screen image is superior to the same image without the lens. I have a 1024X768 DLP . I will replace the remaining lexan on the oil prism with glass and see if there is any improvement. Perhaps its just my building skills but was curious if any of you have seen a marked improvement in the image with your set up?
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My image did not look good using lexan/acryllic sides. Once I switched to glass it looked great. If I could find some more expensive glass it would probably even be better.
Are you saying the image looks worse? We assume you are converting your image output to full frame 1024x768 vs. letterboxed, correct? The idea being, of course, that you re-compress what you've stretched out. Just the concept alone suggests a PQ improvement, as one is squishing lots more scaled detail down into it's proper proportions.
On the other hand I've learned that this business of what is PQ improvement is highly subjective on the eye of the beholder. Speaking for whom I'm able, for my wife and I the difference was obvious. Not to mention the other perks such as no light spill or masking required, etc.
Are you saying the image looks worse? We assume you are converting your image output to full frame 1024x768 vs. letterboxed, correct? The idea being, of course, that you re-compress what you've stretched out. Just the concept alone suggests a PQ improvement, as one is squishing lots more scaled detail down into it's proper proportions.
On the other hand I've learned that this business of what is PQ improvement is highly subjective on the eye of the beholder. Speaking for whom I'm able, for my wife and I the difference was obvious. Not to mention the other perks such as no light spill or masking required, etc.
Yep, squishing tall skinny 1.33 image to 16:9. It doesn't look worse it just isn't much better. Upon close examination it softens the visible pixel structure slightly but also gives an ever so slight softening of the screen image. I was expecting a noticeable improvement. Wasn't sure if it was just my lens assembly or if others noticed the same thing. Thanks for your feedback
So what do you think Joe... did you end up scrapping the idea or are you still using the lense?
Jude,
Thought this thread was dead!
I replaced the lexan with glass and still use the lens. It does control light overspill nicely but I'm still not convinced it makes much of an image improvement, but for the $10 it cost to make its not a big deal either way. I thought some of the other folks that made the lens would chime in and give their honest opinion. Thanks.
Thought this thread was dead!
I replaced the lexan with glass and still use the lens. It does control light overspill nicely but I'm still not convinced it makes much of an image improvement, but for the $10 it cost to make its not a big deal either way. I thought some of the other folks that made the lens would chime in and give their honest opinion. Thanks.
I'm still not finished the build of my projector so I haven't begun building an anamorphic. So I'm looking forward to hearing from others that have built this lens.
zardoz
zardoz
I'm sure that the image probably does soften a little even if you have the most expensive museum glass in your prisms, after all, the image is passing through 4 panes of glass and a couple of inches of liquid. On the other hand, you're gaining a whole bunch of pixels (some may say detail), plus no more grey bars on the top and bottom of your image. But, for everything it seems there must be a price. It's how each of our eyes define that price that makes the difference. It might also depend on the specific projector you're using and it's specifications for how it projects it's image. I'll attest that this lense in my particular case with our varibales for our HT room has been invaluable.
If it's one thing I've learned above all things is that this whole HT forum-thing is very much subjective and what one set of eyes sees can be in some cases vastly different than what another person sees. For every one person that doesn't see much improvement with using this lense, for example, I suspect that there might be 5 to 10 that see a more substantial positive difference.
Same rule of thumb might be applied towards other HT related things, like CRT vs. LCD vs. DLP, etc. There are some things that seem to be constant between those who have an opinion-- for example, CRT seems to have unarguably the best black reproduction -- but! how much better seems to be defined uniquely and subjectively from person to person.
If it's one thing I've learned above all things is that this whole HT forum-thing is very much subjective and what one set of eyes sees can be in some cases vastly different than what another person sees. For every one person that doesn't see much improvement with using this lense, for example, I suspect that there might be 5 to 10 that see a more substantial positive difference.
Same rule of thumb might be applied towards other HT related things, like CRT vs. LCD vs. DLP, etc. There are some things that seem to be constant between those who have an opinion-- for example, CRT seems to have unarguably the best black reproduction -- but! how much better seems to be defined uniquely and subjectively from person to person.
Has anyone made the calculation for a 4:3 to 2.35:1 anamorphic lens. I would eventually like to have two lenses that are interchangable depending on what kind of DVD I am watching.
Hezz
Hezz
So far it's been posted that you can use the existing angles of the prisms themselves, but you have to make a more drastic angle of the actual positioning angle of at least the front prism to compress the image further down. As a result you will get more/some barrel distortion. To place the front prism at a steeper angle mean you need to make it bigger, too, so the image can still pass through the prism without getting clipped at the top.
I plan to try this out in the coming months, and will post my results.
I plan to try this out in the coming months, and will post my results.
JudeBarnes
Can you give us the dimensions of your theatre? Distances such as throw to screen and seating to screen? Screen size etc..
zardoz
Can you give us the dimensions of your theatre? Distances such as throw to screen and seating to screen? Screen size etc..
zardoz
hi zardoz,
i've finished my projector 🙂, AND i am building my second anamorph lense with glycerine. the first worked that good, that one of my friends; with a real projector; bought it from me 🙂; now i am building a new one for my projector and then i will finally send my results to a magazine where people show their hometheatres every month
...
slize
i've finished my projector 🙂, AND i am building my second anamorph lense with glycerine. the first worked that good, that one of my friends; with a real projector; bought it from me 🙂; now i am building a new one for my projector and then i will finally send my results to a magazine where people show their hometheatres every month
...slize
Hi zardoz I'm using a panasonic 75u, the throw of it to an approximately 95" wide DIY blackout cloth screen is about 10-12 feet (throw), and our seating distance is about 8-9 feet from the screen. The projector just sits behind us on a sofa, and I prop up the prisms (believe it or not) each separately every time we watch a movie! ad hoc, I've gotten it down to where I can get it all setup in just a few minutes. We NEVER watch a movie without setting up the prisms, even though it takes an extra minute to get them positioned. In the coming months I'll be making a new set of prisms and have them mounted a little better. At this point I don't plan to mount the projector but it would make things a little more convenient.
here is mine;
http://www.home.no/scipio-ger/randy
the last picture doesn't show the real picture quality; i will post better pics next week; as soon as i get the digi cam again and finished my second anamorph lense.
slize
http://www.home.no/scipio-ger/randy
the last picture doesn't show the real picture quality; i will post better pics next week; as soon as i get the digi cam again and finished my second anamorph lense.
slize
If you had a cylindrical lens of the correct magnification, couldn't you just use that as an anamorphic lens instead of going through all this crap with glass working?
psionic
could you pos a pciture of what u mean; or a sketch or something; i can't imagine how a cylindrical lense should look like...
could you pos a pciture of what u mean; or a sketch or something; i can't imagine how a cylindrical lense should look like...
I have a "cylindrical" shaped anamorphic all-glass lense that I purchased from ebay, which was attached at the end of a movie projector, it's purpose was also to re-adjust the image from tall & skinny to proper proportions.
There ARE lenses that exist already out there that you can use for the purpose of stretching/compressing an image but you have to find the right widths at the rear and front of the lense to allow the entire image to pass through without being clipped at the ends -- that's the tough part because most of them probably will clip your image.
The one which I purchased (just for expiramental purposes) I picked up for around $20 and, although it didn't work perfectly, was fun to try. The image (what you could see) actually did look better and it did squeeze/stretch the image to it's propoer proportions, but I had four big black missing corners on the image.
If you do some research on www.avsforum.com there's a fellow there that posted a certain type of lense he found that would work at least for his projector.
There ARE lenses that exist already out there that you can use for the purpose of stretching/compressing an image but you have to find the right widths at the rear and front of the lense to allow the entire image to pass through without being clipped at the ends -- that's the tough part because most of them probably will clip your image.
The one which I purchased (just for expiramental purposes) I picked up for around $20 and, although it didn't work perfectly, was fun to try. The image (what you could see) actually did look better and it did squeeze/stretch the image to it's propoer proportions, but I had four big black missing corners on the image.
If you do some research on www.avsforum.com there's a fellow there that posted a certain type of lense he found that would work at least for his projector.
I have a slightly off-topic question to anyone experienced here.
Can this anamorphic lens that you guys have built be placed out of focus so that the resulting image is blurred only in the horizontal direction?
Can this anamorphic lens that you guys have built be placed out of focus so that the resulting image is blurred only in the horizontal direction?
Can you give an example of what you mean here.. what exactly WOULDN'T be blurred in your model?
To possibly partially answer your question, one/both of the two prisms can be moved or adjusted such that it creates keystone on the sides, and/or more or less barell distortion depending on the angles you use for each prism.
Some aspects of this project that have been known to lend itself to blurring the image are using really cheap glass, or lexan/plastic which gets slightly bent during the glueing/adhesive process. You could also have water or oil that "spoils". However, it generally blurs the entire image, or distinct portions of the entire image.
To possibly partially answer your question, one/both of the two prisms can be moved or adjusted such that it creates keystone on the sides, and/or more or less barell distortion depending on the angles you use for each prism.
Some aspects of this project that have been known to lend itself to blurring the image are using really cheap glass, or lexan/plastic which gets slightly bent during the glueing/adhesive process. You could also have water or oil that "spoils". However, it generally blurs the entire image, or distinct portions of the entire image.
Im working on a special setup to eliminate the screen door effect. I dont want to get into that here because this thread is about the anamorphic lens.
In order to do this I need a way to blur the image only in the horizontal direction (by setting it out of focus somehow?). I need something similar to motion blur. I just wanted to know if this could be done with one of these anamorphic lenses.
In order to do this I need a way to blur the image only in the horizontal direction (by setting it out of focus somehow?). I need something similar to motion blur. I just wanted to know if this could be done with one of these anamorphic lenses.