DIY anamorphic lens - Page 6

Michael F T · 21st August 2002, 05:24 PM

The long and short of it is that each method of expansion/compression has it's good points and it's bad points.
My pref is solid glass prisms, the company Prismasonic uses 2 acrylic prisms for their anamorphic lens and it's a nice design.
I don't like the idea of having liquid filled prisms getting hot and expanding next to my projector.

I am trying to figure a cost effective way of creating an anmorphic prism with either curved mirrors or 2 (30,60,90) prisms.

I haven't been able to find someone to tell me exactly how they have done it, so it's an experiment that is moving slowly.
However, panavision and other big movie lens makers have used prisms for a long time. And it's very common to expand an elliptical laser so that it is circular. But noone is able to tell me if the angles of the prisms need to be changed for light in the visible wavelengths!!

I even found a guy that has made his own prisms so I'm going to try that route also.

We'll see.

ap0the0sis · 23rd August 2002, 09:59 PM

how much do retail anamorphic lenses cost? Would it be possiblew to purchase one and take it appart and copy it?

ap0the0sis

woneill · 24th August 2002, 09:45 PM

Hi ap0the0sis,

New ones or video projection can cost $$$.

Ebay usually carries used 16mm film ones for between $30 and $70, but their diameter is limited, and they would need additional optical components to get them to work with the large panel projectors most people here are using.

it COULD be done, though, with a little ingenuity.

Bill.

Michael F T · 29th August 2002, 06:30 PM

I read an interesting technic for making water prisms. The long and short of it is that this lady used aluminum foil on each edge and then used silicone. She then used solder to close the joint. She was making the prisms to create rainbows in her home. However she had never been able to make one that didn't leak. Until now.

On Another related subject I have been trying to get some 30 60 90 prisms and I found 2. Small but enough to test if they would work well to expand the image. And the answer is yes. They cost approx $8.00 each but they are too small and don't let enough light through. So I asked for a quote on 100mm ones and it's very expensive $850 for 2.

My latest attempt at getting these prisms is an optical surplus store on the web.

If I could use 45 45 90 prisms I would be done, so many of those around. But it doesn't work with 45 45 90.

I'm sticking with the solid prism method and hope I can find an inexpensive channel for purchasing them.

tonypeps · 4th September 2002, 06:04 PM

No, please don't let this discussion die!

I'm a complete DIY newbie so please bear with me. I have a few questions that have gone unresolved in this thread so far.

Has anyone tried using mineral oil? How does it compare to turpentine?

rwhitley, how did the PVC plastic tubing work for you? Can you please post some pictures?

Has anyone else built a working lens?

Tor, are you using your lens? I checked your updated home theater on your web site and I didn't see it in front of your projector.

Please keep talking everyone, I'm learning a ton!!

Tony

Phil O.son · 20th September 2002, 04:26 PM

Is anything happening here? What I am looking for is the info to do a 2.35 lens.

Has everyone else just finished their 16:9 lens and been happy enough to just go away satisfied or are you all too busy to experiment further?

I bought the ViSR 2.35 lens but it would only contract and I need to do an expand version. I downloaded the DECinema excel spreadsheet but can't make sense out of it. Does anyone have an english translated version? I tried sending him a PM but got no reply.

TIA,
Phil

Phil O.son · 23rd September 2002, 09:55 PM

Anyone?, Anyone?

woneill · 24th September 2002, 10:51 PM

Most, if not all, anamorphic lenses use achromatic prisms set at an angle that compresses the image vertically.

If you wanted to expand the image as well, you could go either for a shorter focal length (wider angle) objective lens, or try using a combination of cylindrical lenses instead of prisms.

Good cylindrical lenses are hard to find, though...

Bill.

Phil O.son · 25th September 2002, 06:45 AM

Bill,

You can turn a prism lens into an expander by reversing it and rotating it 90 degrees. Some statements I read claim that the lens actually works better that way. I need an expander so that's how I will mount mine. The main thing I don't know is what are the correct angles for the 2.35 version.

Also, although I have the turpentine prism at 24 degrees, and the water at 30 degrees, I don't know the relationship between the two. The info on Arne's site seems ambiguous since his drawing doesn't seem to agree with the values he has, (-3.2 degrees, 31 degrees). It would be nice if I could get some clarity on these numbers.

TIA,
Phil

ccarrigan · 22nd October 2002, 07:59 PM

I would love for this thread to continue. I have tried making my own but to no success. Both prisms leaked. I could not find a good way to accurately cut both glass and plexiglass. Hopefully Tor will post his plans on how he did it

I'd like to see one based on mirrors like the Prismasonic and see those results of a DIY posted here. I'm off to do a DIY subwoofer and hopefully have that one not leak like my prisms did.

29th August 2002, 06:30 PM	#54
Michael F T diyAudio Member Join Date: Aug 2002 Location: NY NY	Using aluminum foil on water prism I read an interesting technic for making water prisms. The long and short of it is that this lady used aluminum foil on each edge and then used silicone. She then used solder to close the joint. She was making the prisms to create rainbows in her home. However she had never been able to make one that didn't leak. Until now. On Another related subject I have been trying to get some 30 60 90 prisms and I found 2. Small but enough to test if they would work well to expand the image. And the answer is yes. They cost approx $8.00 each but they are too small and don't let enough light through. So I asked for a quote on 100mm ones and it's very expensive $850 for 2. My latest attempt at getting these prisms is an optical surplus store on the web. If I could use 45 45 90 prisms I would be done, so many of those around. But it doesn't work with 45 45 90. I'm sticking with the solid prism method and hope I can find an inexpensive channel for purchasing them.

4th September 2002, 06:04 PM	#55
tonypeps diyAudio Member Join Date: Sep 2002 Location: Naperville, IL	Please continue!!! No, please don't let this discussion die! I'm a complete DIY newbie so please bear with me. I have a few questions that have gone unresolved in this thread so far. Has anyone tried using mineral oil? How does it compare to turpentine? rwhitley, how did the PVC plastic tubing work for you? Can you please post some pictures? Has anyone else built a working lens? Tor, are you using your lens? I checked your updated home theater on your web site and I didn't see it in front of your projector. Please keep talking everyone, I'm learning a ton!! Tony

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21st August 2002, 05:24 PM	#51
Michael F T diyAudio Member Join Date: Aug 2002 Location: NY NY	The long and short of it is that each method of expansion/compression has it's good points and it's bad points. My pref is solid glass prisms, the company Prismasonic uses 2 acrylic prisms for their anamorphic lens and it's a nice design. I don't like the idea of having liquid filled prisms getting hot and expanding next to my projector. I am trying to figure a cost effective way of creating an anmorphic prism with either curved mirrors or 2 (30,60,90) prisms. I haven't been able to find someone to tell me exactly how they have done it, so it's an experiment that is moving slowly. However, panavision and other big movie lens makers have used prisms for a long time. And it's very common to expand an elliptical laser so that it is circular. But noone is able to tell me if the angles of the prisms need to be changed for light in the visible wavelengths!! I even found a guy that has made his own prisms so I'm going to try that route also. We'll see.

23rd August 2002, 09:59 PM	#52
ap0the0sis diyAudio Member Join Date: Jul 2002 Location: Miami FL	how much do retail anamorphic lenses cost? Would it be possiblew to purchase one and take it appart and copy it? ap0the0sis

24th August 2002, 09:45 PM	#53
woneill diyAudio Member Join Date: Jun 2002 Location: Somewhere in Sunny NJ	Hi ap0the0sis, New ones or video projection can cost $$$. Ebay usually carries used 16mm film ones for between $30 and $70, but their diameter is limited, and they would need additional optical components to get them to work with the large panel projectors most people here are using. it COULD be done, though, with a little ingenuity. Bill.

20th September 2002, 04:26 PM	#56
Phil O.son diyAudio Member Join Date: Sep 2002 Location: Kenwood	Is anything happening here? What I am looking for is the info to do a 2.35 lens. Has everyone else just finished their 16:9 lens and been happy enough to just go away satisfied or are you all too busy to experiment further? I bought the ViSR 2.35 lens but it would only contract and I need to do an expand version. I downloaded the DECinema excel spreadsheet but can't make sense out of it. Does anyone have an english translated version? I tried sending him a PM but got no reply. TIA, Phil

23rd September 2002, 09:55 PM	#57
Phil O.son diyAudio Member Join Date: Sep 2002 Location: Kenwood	Anyone?, Anyone?

24th September 2002, 10:51 PM	#58
woneill diyAudio Member Join Date: Jun 2002 Location: Somewhere in Sunny NJ	Most, if not all, anamorphic lenses use achromatic prisms set at an angle that compresses the image vertically. If you wanted to expand the image as well, you could go either for a shorter focal length (wider angle) objective lens, or try using a combination of cylindrical lenses instead of prisms. Good cylindrical lenses are hard to find, though... Bill.

25th September 2002, 06:45 AM	#59
Phil O.son diyAudio Member Join Date: Sep 2002 Location: Kenwood	Bill, You can turn a prism lens into an expander by reversing it and rotating it 90 degrees. Some statements I read claim that the lens actually works better that way. I need an expander so that's how I will mount mine. The main thing I don't know is what are the correct angles for the 2.35 version. Also, although I have the turpentine prism at 24 degrees, and the water at 30 degrees, I don't know the relationship between the two. The info on Arne's site seems ambiguous since his drawing doesn't seem to agree with the values he has, (-3.2 degrees, 31 degrees). It would be nice if I could get some clarity on these numbers. TIA, Phil

22nd October 2002, 07:59 PM	#60
ccarrigan diyAudio Member Join Date: Oct 2002 Location: Hilton Head, SC	I would love for this thread to continue. I have tried making my own but to no success. Both prisms leaked. I could not find a good way to accurately cut both glass and plexiglass. Hopefully Tor will post his plans on how he did it I'd like to see one based on mirrors like the Prismasonic and see those results of a DIY posted here. I'm off to do a DIY subwoofer and hopefully have that one not leak like my prisms did.

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