No pix attached. Best to open a photobucket account and then use the image attach feature. That is how I went from thumbnails to full size images I attach now...
Mark
Mark
prisms arrived
Mark,
I know you can eyeball the angles and get them correct, but for those of us who are new to this game, can you give the angles of the glass prisms to give the 1.33 stretch.
Note, if you could give the angles relative to the flat bottom surface or the lens, I think my feeble mind could understand that. Thanks,
Scott
Mark,
I know you can eyeball the angles and get them correct, but for those of us who are new to this game, can you give the angles of the glass prisms to give the 1.33 stretch.
Note, if you could give the angles relative to the flat bottom surface or the lens, I think my feeble mind could understand that. Thanks,
Scott
Found them locally
I live in the Houston, TX area and I found a Trophy shop that has them instock (Medium size) I will go buy tommorow and check them out. A simple drawing with angles written on would be great!
Thanks,
Mike
I live in the Houston, TX area and I found a Trophy shop that has them instock (Medium size) I will go buy tommorow and check them out. A simple drawing with angles written on would be great!
Thanks,
Mike
Re: Found them locally
The angles might vary due to the thickness (where mine are 2" or 50mm at the base), so would only be a guide if that...
TIP for 3 step alignment.
1. Place them together to form a solid block with the apexes opposed in front of your projector and align the rectangle of light so that you are flush top to bottom for the 16:9 area of the centre of the screen.
Table mounting might be the go here if your new to this. I recommend placing the 90degree sides in together so that you use the hypotinuse of the triangle (in plan) as the front and rear faces. It is the largest area, so will ensure the best results.
2. Then start by moving the thick end of the front prism out towards the screen. Your screen should be 2.37:1 BTW not 2.35:1. What you should see is the side that the prism in on should start to stretch, IE, I have my lens set up with the front prisms out on the left, and it controls the left side of my screen...
3. Now slowly bring the thin end of the rear prisms towards the projector. This prism will be on the right, and it will control the right hand side.
You are stretching the light beam, so you need a straight 16:9 image to start with first. If you have keystone or other errors including a non level image, the lens will only magnify the problems as it stretches the light...
There should be about (for mine anyway) 40 degrees bewteen the front and rear faces...but the ultimate test is projection onto the screen at 2.37:1...
That is cool. Are they the same price as on the 'net?
Mark
sdspga said:
The angles might vary due to the thickness (where mine are 2" or 50mm at the base), so would only be a guide if that...
TIP for 3 step alignment.
1. Place them together to form a solid block with the apexes opposed in front of your projector and align the rectangle of light so that you are flush top to bottom for the 16:9 area of the centre of the screen.
Table mounting might be the go here if your new to this. I recommend placing the 90degree sides in together so that you use the hypotinuse of the triangle (in plan) as the front and rear faces. It is the largest area, so will ensure the best results.
2. Then start by moving the thick end of the front prism out towards the screen. Your screen should be 2.37:1 BTW not 2.35:1. What you should see is the side that the prism in on should start to stretch, IE, I have my lens set up with the front prisms out on the left, and it controls the left side of my screen...
3. Now slowly bring the thin end of the rear prisms towards the projector. This prism will be on the right, and it will control the right hand side.
You are stretching the light beam, so you need a straight 16:9 image to start with first. If you have keystone or other errors including a non level image, the lens will only magnify the problems as it stretches the light...
There should be about (for mine anyway) 40 degrees bewteen the front and rear faces...but the ultimate test is projection onto the screen at 2.37:1...
mfeidler said:
That is cool. Are they the same price as on the 'net?
Mark
Thanks Mark. Through trial and error I have come up with my settings. A couple observations:
1) One can REALLY bend the light. Throwing from 14', I could get a 10' wide image with no problem and not much geometric distortion.
2) Too wide is a real concern. Had the wife come down to get her impressions. Was showing LOTR, Return of the King. During the final battle scene, her first comment was "I really like the wider, bigger screen" That soon turned to "I feel like I am in one of those IMAX theaters". After about 5 minutes she said "I feel dizzy. I'm going upstairs."
3) No detail was lost with these prisms. I fully agree that using the full panel enhances the PQ as well as brightness. Unbelievable picture!
While these prisms can make huge picture adjustments, finding a comfortable viewing size is still of primary concern. As I am viewing from 11', I think under 9' is the better size for me.
Finally, you are right in that you need an enclosed box for these prisms. While I taped the edges with black electrician's tape, I still had images on the left and rear walls. Actually the left side one scared the crap out of me during one of the battle scenes because we had all the lights off and I picked up movement in my peripheral vision
1) One can REALLY bend the light. Throwing from 14', I could get a 10' wide image with no problem and not much geometric distortion.
2) Too wide is a real concern. Had the wife come down to get her impressions. Was showing LOTR, Return of the King. During the final battle scene, her first comment was "I really like the wider, bigger screen" That soon turned to "I feel like I am in one of those IMAX theaters". After about 5 minutes she said "I feel dizzy. I'm going upstairs."
3) No detail was lost with these prisms. I fully agree that using the full panel enhances the PQ as well as brightness. Unbelievable picture!
While these prisms can make huge picture adjustments, finding a comfortable viewing size is still of primary concern. As I am viewing from 11', I think under 9' is the better size for me.
Finally, you are right in that you need an enclosed box for these prisms. While I taped the edges with black electrician's tape, I still had images on the left and rear walls. Actually the left side one scared the crap out of me during one of the battle scenes because we had all the lights off and I picked up movement in my peripheral vision
sdspga said:Thanks Mark. Through trial and error I have come up with my settings. A couple observations:
1) One can REALLY bend the light. Throwing from 14', I could get a 10' wide image with no problem and not much geometric distortion.
2) Too wide is a real concern. Had the wife come down to get her impressions. Was showing LOTR, Return of the King. During the final battle scene, her first comment was "I really like the wider, bigger screen" That soon turned to "I feel like I am in one of those IMAX theaters". After about 5 minutes she said "I feel dizzy. I'm going upstairs."
3) No detail was lost with these prisms. I fully agree that using the full panel enhances the PQ as well as brightness. Unbelievable picture!
While these prisms can make huge picture adjustments, finding a comfortable viewing size is still of primary concern. As I am viewing from 11', I think under 9' is the better size for me.
Finally, you are right in that you need an enclosed box for these prisms. While I taped the edges with black electrician's tape, I still had images on the left and rear walls. Actually the left side one scared the crap out of me during one of the battle scenes because we had all the lights off and I picked up movement in my peripheral vision
Yes I'm down to a 4" x 5" side reflection that I will fix by simply adding a piece of MDF to the base under the projector. Other then that, I have fixed all other problems with mine...
Viewing angles for cinema scope 2.37:1 video will differ slightly to what is excetable (or preferred) for 2.39:1 for film. Where film wants you at or closer than 36 degrees, I think video works the other way. You don't want to be closer then 36degrees at home given the source (DVD) is SD, not HD. HD DVD and or BrD might change this, but for right now, you want to be back a little more, or reduce your screen height which ultimately affects the width.
There is an exellent diagram for working out the best and worst seating locations which I am attaching HERE.
Right now I have an 8 foot wide screen and my back row is 1.54 time the screen width. The front row is 1.54 times the 1.78:1 screen width.
Soon I will have to reduce the image width to just 7 feet or mabe less when I move. Naturally, my screen height changes as well, but the point is, the viewing angle keeps the size of the angle constant relative to the seating distance (if that make any sense)...
So basically, I belive you should not be seated any closer than 1.54 times the screen width for a "scope' set up. If you are talking about 16:9, then work of the height and times that by 3.68.
When I design a room, I actualy take the room length and divide that by 2.17 first. This gives me the screen's width for that room based on SD video and this idea works really well. You may be surprised just how large a screen can still be.
Take the screen width and times that by 1.54 gives you a perfect 36 degree veiwing angle, as well as keeps your seats off the back wall, so make s your sound system work better too...
So back on topic, I am really glad that your lens is working out. Can you post some pix?
Mark
sdspga said:Actually the left side one scared the crap out of me during one of the battle scenes because we had all the lights off and I picked up movement in my peripheral vision
Maybe there's a market for this! Surround Video!
(Sorry for the double post. This site has some weird edit rules...)
Incidentally, this project is driving me crazy! It couldn't have come at a worse time for me. I am working like crazy, then come home, spend some time with the kids, help put them to bed, then have about 1/2 hour to work on this thing. Needless to say, I am not getting very far.
But my second small wedge came in yesterday, so I was able to at least take my raw materials and start sizing things up. Everything should work out well, assuming I use the proper adhesive. My father actually stopped by last night for an hour or so, and he was very intrigued by the whole project. He's as cheap, if not cheaper than me, so when I showed him the prices on the Pr**sonic page for these things, he became especially interested.
Incidentally, this project is driving me crazy! It couldn't have come at a worse time for me. I am working like crazy, then come home, spend some time with the kids, help put them to bed, then have about 1/2 hour to work on this thing. Needless to say, I am not getting very far.
But my second small wedge came in yesterday, so I was able to at least take my raw materials and start sizing things up. Everything should work out well, assuming I use the proper adhesive. My father actually stopped by last night for an hour or so, and he was very intrigued by the whole project. He's as cheap, if not cheaper than me, so when I showed him the prices on the Pr**sonic page for these things, he became especially interested.
Thanks for the 3-step program, Mark 😀 It will really help.
I just ordered my "trophies". As soon as I told her the sizes I wanted she knew I wanted them blank. I didn't even have to tell her! This is a gas... I can't wait to get the prisms after reading the latest posts.
If these work out this will have to be the find of the century.
sdspga, your wife's comments made me laugh out loud!
Andy
I just ordered my "trophies". As soon as I told her the sizes I wanted she knew I wanted them blank. I didn't even have to tell her! This is a gas... I can't wait to get the prisms after reading the latest posts.
If these work out this will have to be the find of the century.
sdspga, your wife's comments made me laugh out loud!
Andy
They do and it is 😀andy238 said:
This just goes to show how some think out side the square, again well done Steve and Fisher.
I spent most of the last year looking in optical stores, had found plenty of items made from the same crystal, but they were all cubes, or rectangular prisms, no wedges.
Found a manufacture of BK7 with optic coating which turned out to be more expensive than the ISCO III...
I would never have thought to try a trophy shop...
Mark
I was able to make some good progress yesterday. Since I am using two of the same size wedges, I just made a rectangular box from mdf. I actually bought the mdf as precoated shelving--so they are nice and uniform white, with very smooth edges.
I found a good epoxy, and am using brass rivets on the bottom for the point of rotation. These I glued to the bottom of each wedge pretty much in the middle.
On the top, I am using a screw with a 1 inch flat head (don't know what they are called--but the head is very wide), the flat head part will be adhered to the top of the wedge. The screw will traverse a hole in the top of the box, and stick out a little bit over the top. I am using a dial bought from the local hardware store that fits over the shaft of the screw that sticks up through the top of the box.
To lock in the settings, I have a plastic disk that will be glued to the top of the box under the dial. The dial will have a round nub underneath (still figuring out where the nub will come from--I think a small round-head screw in the dial should work). There will be three depressions in the plastic disk so that the nub on the dial will tend to settle in the depressions on the disk. This should be enough to lock in the dial for the pass through, 16:9 and 21:9 settings.
If I have the time, I would like to finish tonight. I'll try to post some pics when I am done.
I found a good epoxy, and am using brass rivets on the bottom for the point of rotation. These I glued to the bottom of each wedge pretty much in the middle.
On the top, I am using a screw with a 1 inch flat head (don't know what they are called--but the head is very wide), the flat head part will be adhered to the top of the wedge. The screw will traverse a hole in the top of the box, and stick out a little bit over the top. I am using a dial bought from the local hardware store that fits over the shaft of the screw that sticks up through the top of the box.
To lock in the settings, I have a plastic disk that will be glued to the top of the box under the dial. The dial will have a round nub underneath (still figuring out where the nub will come from--I think a small round-head screw in the dial should work). There will be three depressions in the plastic disk so that the nub on the dial will tend to settle in the depressions on the disk. This should be enough to lock in the dial for the pass through, 16:9 and 21:9 settings.
If I have the time, I would like to finish tonight. I'll try to post some pics when I am done.
Sorry, Mark. I was referring to the angles of the prisms to get the correct stretch. I was experimenting and like I said, one can really bend the picture. I am having a little barrelling at the bottom, but really no pinchusioning.
I am hoping you (or anyone else for the matter) can shed some light on what the angles of the prisms should be to correctly stretch the image into the proper AR. Thanks,
scott
sdspga said:
If I get this contaption up and running tonight, I should be able to give some pretty exact angle measurements for you.
I don't know, at this point, which angles are ideal--but I foresee that there could be some pretty complicated results--because we have two prisms that could be any angle in relation to a standard (let's say a line across the face of the box, and in relation to each other. Does the optimal angle between the two prisms change depending on the angle of the first prism relative to the projector? IN other words, in these two drawings, both have about the same angle between the prisms, but each one is different relative to the projector. Does that matter? Hopefully, I'll find out...
Steve, if you bring in the apex of the front prisms just a touch (mine do touch), I think you have it 🙂
Remeber, because the rear prisms's full width is not needed, you can have a slight over lap as well. I found doing this gave better result as well as fitting in to the case I made...
Mark
Remeber, because the rear prisms's full width is not needed, you can have a slight over lap as well. I found doing this gave better result as well as fitting in to the case I made...
Mark
Mark...its me, cpc from AVS 🙂
Sounds cool. If these are doable, I would love to try one out myself. I can't read all this now though. Phew! 🙂
Sounds cool. If these are doable, I would love to try one out myself. I can't read all this now though. Phew! 🙂
...and you may just possibly gain a customer...😀 that is if one day you will let me drop in with a case of beer to see your contraption in action! I am in Ajax. I travel pretty far for home theatre stuff if its worth it 😎 I want to setup a constant height deal with my Hitachi TX200 so I can view 2.35:1 at full height.
I got far enough to test the housing with the lenses inside. I epoxied the rivets on the bottom of the lenses, drilled a couple of holes in MDF, put a couple of sides on the box (no top yet) and set it up in front of the pj so I could easily rotate the lenses.
Couple of observations. (Remember--I have a 4:3 projector). With this setup, even with the two small lenses, I can get some significant stretch. One sample I measured at 2.55:1! There is some significant distortion at those stretch levels, and it is really hard to get the geometry correct. I was able to get the top, bottom and left side of the image pretty square, but the right side was significantly bowed. Once I got the image down to about 2.3:1 I was able to decrease the distortion, but not rid it completely. Also, there was significant CA on the sides of the image at these levels. My wife helped me measure the images with a tape measure, and she kept commenting on the "petty colors" on the sides of the image.
Once down to 1.78:1 (which is shown in the following images), I was able to get geometry pretty exact, with no significant CA. The picture was pretty focused all the way across the image.
Would love to play with some test patterns.
Conclusion--2.37:1 is most likely going to be too difficult to accomplish from 4:3, which is too bad. 16:9 from 4:3--easily doable, and the image rivals my panamorph (if not clearer, actually). So going 21:9 from 16:9 projector will be a cinch, and the quality is pretty darn good.
Couple of observations. (Remember--I have a 4:3 projector). With this setup, even with the two small lenses, I can get some significant stretch. One sample I measured at 2.55:1! There is some significant distortion at those stretch levels, and it is really hard to get the geometry correct. I was able to get the top, bottom and left side of the image pretty square, but the right side was significantly bowed. Once I got the image down to about 2.3:1 I was able to decrease the distortion, but not rid it completely. Also, there was significant CA on the sides of the image at these levels. My wife helped me measure the images with a tape measure, and she kept commenting on the "petty colors" on the sides of the image.
Once down to 1.78:1 (which is shown in the following images), I was able to get geometry pretty exact, with no significant CA. The picture was pretty focused all the way across the image.
Would love to play with some test patterns.
Conclusion--2.37:1 is most likely going to be too difficult to accomplish from 4:3, which is too bad. 16:9 from 4:3--easily doable, and the image rivals my panamorph (if not clearer, actually). So going 21:9 from 16:9 projector will be a cinch, and the quality is pretty darn good.
Hi cpc,morkys said:
The cystal prism discussion starts at about page 60 or 61 but ideally you should start at page 1 🙂
Steve Scherrer said:
Steve, those images are so muchg better than yor other shots. Very well done. I think 33% is all your going to get out of the lens, so 12:9 to 16:9, and then 16:9 to 21:9...
Inertesting that you didn't need to shorten one side of the case. It must just be my very short throw projector...
Mark
Looking tremendously good guys. I am tempted to order some and I don't even have a pj yet (and have debated going CRT).
Mark, did you wind up ordering any of the US wedges? Just wondering if anyone is going to do a first hand comparison of the Aussie trophy optics to the US trophy optics.
Mark, did you wind up ordering any of the US wedges? Just wondering if anyone is going to do a first hand comparison of the Aussie trophy optics to the US trophy optics.