Cheap coating opportunity for USA prisms - Page 7

Well - I just popped over to the DIY Screen forum, and, I will see you guys in a few months...

Thanks!

-- Keith

There is a bit of reading over there

Mark

Mark, where did you find those. I might check HD on the way home today. I need to do something with my setup (got it from you) I finally mounted the PJ and Sled and Lens. I was about to screw the frame to get the proper tilt until I saw that statement. Thanks for saving your .. I meam my Lens frame from sure destruction.

-- Russell

Russell,

I sourced the Perspex from the same plastics guy that made the original water prisms for me back in 2005. It is just a 360mm square plate that I attached to the base of the projector using the 4 M5 bolts on the bottom on the unit.

I lined the plate centre to the main MDF board, drilled holes right through and then used springs to space the perspex away from the MDF. The springs compress to allow precise adjustment. I didn't include the Perspex with the sled as there was too many variables with different makes and model projectors.

Take a look at the image to see how I did mine...

Mark

I already have build something and used wing nuts similiar to what you have to mount my projector ( I have 4 - 5 inch screws sticking out for adjustment). I thought you where refering to the nuts/screw used for the lens tilt. It seems that whatever I do, no matter how tight I make the 2 outside screws the lens always seems to move.

There is a fair amount of weight there, but I not had any problems with lens tilt in the past...

Mark

What's the size of those 2 screws. I hate metric.

They're actually imperial - 3/16" x 1.5". I used imperial as I knew it would be easier to find than say an M5 bolt. If they're not tightening up, the tee nuts may have striped out from the MDF...

Mark

After seeing how small those french prisms are, I was wondering if you could get by with the Crystal Factory CWD46 lenses (4" x 6") as opposed to the 5"x7" ones everyone in this thread ordered.

If you could do it over would you use the smaller ones? Would the smaller ones still work? Thanks.

I finally put together the case and the slide mount for these lenses. Put the prisms in the projector light path and tested with the anamorphic HCFR image. I am noticing very bad chroma aberration only on the right side. On the left side, its way way lower. Just to give the idea about prism placement, this is the view from the top. The projector and lens is ceiling mounted.

Also, one thing that I notice, each lens is expanding only on one side and have very little effect on the another. Is this how its supposed to mean?

That is my experience as well. Each prism expands half of the image.

The CA on the side can be remedied using masking.

Well, the right 25% side of the screen is badly affected by the CA. If I can somehow make the CA uniform, by reducing it on the right side and increase on the left.

Any ideas? some position change in the prisms?

Okay, I played around the distance between two prism and noticed that one prism was tilted little bit in other direction as well. I made it straight and CA on both sides became uniform.

Also, one thing to remember. The picture on the screen without the lens should be exact square. Any distortion in the shape will be magnified by the anamorphic lens.

Now back to enjoying movies.

A. Dude

Is L&L still doing this?

I guess it would have been easier if I just called them. I just talked to a gentleman there and they will do the one-off's like me. $80 + shipping, and I can't argue with that. They will just work the lens in with another order so we don't have to pay the $500+ that it would be for a custom order. AWESOME.

I'd still like to see some side-by-sides of the coated prism-based lenses compared to the professionally made lenses. Anyone tried this?

In my shoot out last year...

Mark

I believe Mark/Cavx did that on his website...http://cavx.blogspot.com/2008/01/ana...shoot-out.html

edit: Sorry...I forgot to hit the post button last night.

Kudos, Mark - very respectable given the $2500 (US) price difference between yours and the commercial lenses. Do you have any additional close-up of the outer 1/3 of the screen? I'm particularly interested in the focus in a real-world image in the outer edges of the frame as I think this would be the most distracting issue for me.

Thanks!

Thanks I will document the benefits soon as I develop the "CAVX Corrector". I have a prototype in development (a work in progress) now...

I will also have a 1080projector by the end pf the week too!!!

Mark

CAVX,

Any update on your latest lens?

Normally I would breaking rules, but seeing as how you asked, coated prisms will be available soon and I am also hoping for (in limited numbers) achromatic doublets for CA correction...

Mark

This is pretty exciting. I thought you already investigated this and ruled it out!

Never say never

Mark

This looks promising. I am on the verge of re-doing the anamorphic lens. I am thinking of two ways:
Option 1 - Build a lens from the guts of Hi-Lux Variable anamorphic lens. It has prisms + some kind of correction glass in the front. This lens is meant for long throw, so prisms are too small for projector use. I noticed that the prisms have lot of gap at the beginning, between the prisms and the end. If I can build a smaller housing for these prisms, the image may just fit on these.

In my short test of the Hi-Lux, it looked lot sharper than the my current DIY lens.

Option 2 - Avoid all the hassle and go with the Aussimorphic III. I guess it will be better to wait.

I never used my prisms
I was cleaning the basement and found them new in box.
Anyone want them?

Hey Mark, can i get your MKII lenses coated ? Or are they and thets the best it will get

Of course you can Proper multi broad band coatings will be way better than the "anti-reflective" coatings they gave me on the glass at production.

Interesting. Where do i go from here.....

From page 1 of this thread:


Which is partly why good optics cost as much as it does.

Still worth giving them a call though.