DIY anamorphic lens

Coated Prisms

Hi everyone,

I'm a long time lurker and occasional contributer (around the time Mark started using the trophy prisms).

For those that haven't seen it, here is a French forum where they have done a lot of work on anamorphic prisms (if you don't read French, AltaVista's Babelfish works reasonably well):

http://www.homecinema-fr.com/forum/viewtopic.php?t=29803723

They have designed a prism pair specifically for the purpose and get them made in batches from BK7 with an anti-reflective coating. They sell these for 95 euros including some freight (about USD$ 125) for the pair and are getting numbers for the next batch at:

http://www.commandes-groupees.fr/viewtopic.php?p=4384

Enjoy,
Greg
 
Hi Mark,

How are you? I may be travelling to Brisbane later this year and it would be great to meet you.

I think they are the same size as the earlier runs, however no one over there seems to be complaining about size. Because the prisms have a wider internal angle, I believe they arrage them in a 'flatter' configuration, i.e. the exit surface is wider because the prism is on less of an angle. They also prefer VC to your HE.

Time you upgraded you projector anyway 😀

Greg
 
Prism's ordered. I snagged 5x7's both to make sure I have enough size in the prism, and so I can play around with placement more. I have two possible setups in mind. We'll see how ambitious I really am 🙂 In all probability I'll play around for a few days, get distracted, and then they'll gather dust for a while till I come back to the project for another couple days, then more dust... and the time between can stretch out to years. 😉

But it's fun.
 
Haven't arrived yet. They had to order them before they could ship.

Besides that, I've done naught at home this week but sleep and grab a quick shower. And not enough sleep, at that. All the rest at work. The extra hours will be buying me a projector upgrade, I think!

I'm on the train home at the moment or I'd never get any fun browsing time!

C
 
Ahh, a weekend distraction!

I snagged two of the 5x7 prisms (crystal wedges) from The Crystal Factory and have discovered they don't need to be that big - the image is only about 3"x4" on the outside of the second prism. I'm throwing a ~100" wide anamorphic from about 11'8" (currently an X1) They're identical as far as any tools to measure angle, etc. that I have can measure. So I have tons of flexibility as far as placement goes.

I've determined (pretty "duh" once I messed with it) that you'll never be wanting to have the two prisms anything other than exactly perfectly parallel to each-other. So that bodes well for the one setup I think I'm going to try.

This should be fun. Which is very much needed. I managed to keep my hours under 60 this week. (59.5...) :smash: :smash: :smash:

C
 
Some photos of my setup

Thought I'd share these since I appreciated it so much when others did the same. My theater room is pretty low end, but it works for me. 😀

IMG_0004.jpg

Lens enclosure "prototype"
IMG_0003.jpg

Seating area
IMG_0023.jpg

Lens + HS10
IMG_0002.jpg

Screen for 16:9
IMG_0026.jpg

Screen for 2:35:1
IMG_0027.jpg

Masking panel close up
IMG_0034.jpg

"Memoirs of a Geisha" screen cap


Screen shot is not very good, it's the only one I had that came out halfway decent, I need to learn more about how to use the digital camera I just got (Canon PS A630). Still need to build a new enclosure for the lens, too since I still have a 2" offset when it is in place vs slid out of the way. For now I am just adjusting the HS10 mount each time, but that is getting old.
 
Yes, I based it on the other designs I'd seen here. I really wasn't sure what I'd need so I allowed for as much fine tuning as possible. As is turns out, there's not much dependence on the angle of tilt so it's a bit of overkill. When I get some motivation I'll build a nicer looking one and probably won't need them.