[watchmeexplode55]

I recently made a anamorphic lens for my epson 8700ub. I followed the guide here http://www.zuggsoft.com/theater/prism.htm . It seemed pretty simple and I have made my housing lined with black velvet. The problem I have run into is that when I slide my lens into place, the image dims greatly. I normally run my projector in THX mode, but when the lens is in place I have to place my projector into living room or dynamic mode to get a bright picture such as the one I am accustom too in THX (without the lens in place). This is causing some color issues of course, and skin tones to be off. If anyone could help shed some light on this issue, it would be much appreciated. I'm new to the whole projection setup and I don't really have any ideas.

Thanks so Much

 

[Brad Horstkotte]

So, "greatly" dims as in more than if you just zoomed the image to fill the 2.35:1 screen (without the lens in place)?

 

[watchmeexplode55]

Yes. Sorry if I wasn't as clear as I could have been. When zooming the dimming from the original is very minimal. But when when I use my lens it is very dim. I would say that the lens dims the image by 20% or so. Where when I zoom their is little to no dimming that can be noticed by my eyes.

 

[CAVX]

What prisms did you use? If you have used "trophies", then dimming and other aberrations are to be expected.

 

[watchmeexplode55]

I used trophies from precision crystals. So it's just a matter of living with the dimming than?

 

[CAVX]

So you know there is no optic coating on these and they have no correction right?

 

[watchmeexplode55]

Yes, I know that there is no coating and no corrections. I knew I would get some chromatic aberration and pin-cushioning (although my throw ratio is 2.2 so pin-cushioning is very minimal), but in the article above, on how to make the lens, says nothing about expecting dimming. This is why I asked here, to make sure I wasn't overlooking some simple mistake I may have made.

 

[CAVX]

Your taking 1.78:1 and spreading it out to 2.37:1. Something has to give. Re-calibrate for "Lens In" and you should get a better result.

 

[Highjinx]



Quote:
Originally Posted by watchmeexplode55 /forum/post/20768580


Yes. Sorry if I wasn't as clear as I could have been. When zooming the dimming from the original is very minimal. But when when I use my lens it is very dim. I would say that the lens dims the image by 20% or so. Where when I zoom their is little to no dimming that can be noticed by my eyes.

In that case wouldn't you be better off zooming?