I'm currently getting ready to convert my setup to a vertical arrangement. After looking through many examples and success stories it seems that having the mirror between the field lens and the triplet at a fixed angle is the way to go. Why? I think it looks more advantageous to put the mirror after the triplet on a pivot so that it can be used to adjust the throw angle to the screen. I'm assuming the reason people move the mirror between the triplet and the field lens is to cut down on the height of the box. If I don't care that my box is 3ft tall should I just stick with the mirror on top? The height savings doesn't do me any good if it has to be perpendicular to the screen at the center. Are these designs just having the PJ sit on the floor and then angling up at the screen?

So... anyone got opinions on pro/cons to mirror between field lens and triplet or after triplet? If this has been discussed somewhere else I'd appreciate a link because I haven't found it in my searches... otherwise this looks like a good place to raise some discussion.

I'm thinking of verticalizing my pj too..the main arguments I've seen for the mirror inside the pj
is either becausde its shorter or because the mirror will stay cleaner(less exposure to dust,smoke etc) .... I've actually seen a couple of pjs that are angled inside the box (so they project at a set keystone angle) ... and I'm not absolutely sure but I don't think the angle of the mirror placed after the triplet will do the same as keystoning will, it will just make your picture trapezoidal shaped , but not correct for the keystoning angle

I believe the spirit of the folded design is to try to cut down the size of the pj itself. If space is not an issue for you then just slap a mirror on the top!

Alright... since space isn't an issue that's probably just what I'll do (slap it on top). I'm aware of the keystoning myth. I'll correct that with the field lens tilt, not the mirror.


Oh yea.. btw I'm not sure I have to be real concerned about exposure to smoke... if anything starts on fire it'll probably be the PJ itself. I could see dust being a problem but I doubt that can be any worse than having hte triplet exposed.

1. Tilting the mirror will not correct keystone, in or out of the projector.

2. While an external mirror may be more prone to collecting dust, it's also easier to clean that dust off.

I'll be using an internal mirror myself, though I don't expect it to save me any space. I just think it will end up being a more attractive build.

ahhhh

I have a mirror, which was normal mirror glass,, stripped backing with paint stripper,, vulaaa FS mirror,, it is temp outside,, as my orig build is a haas,, it is now vertical, with mirror,, got sick of image reverse software,,
........... due to my exclusive trippy style 4" by 4" new polariser..........
so now i have a haas in shuttle launch posistion,, but hehehhe

because PJ was on a stand using two bolts,, I have keystoning by tilting PJ accordingly,,,, so simple but very effective...

Yes but doesn’t the mirror still needs to be in the centre of the screen to avoid keystone distortion?

DJ

How does one get sick of image reverse software?
Does it not work some of the time?

Has anyone evaluated placing the FS mirror between the collimator and LCD? Is the 20mm distance between the two critical? Will light scatter too much at that distance?

It seems that if through a height adjustment mechanism you can keep your LCD, collector lens and triplet parallel to the screen and not have to worry about keystoning.

I went to a glass store to get a mirror and the guy said that the backing is the reflective silver and it will just be glass if you take it off. So I got a sample peice and have soaked it in paint thinner all night and nothing seems to be taking it off. Any suggestions?

The mirror I got ($3.00 at Hobby Lobby) had what looked like a painted back. It stripped right off with paint stripper. I did have to rub it off with a gloved hand (it didn't get soupy, it sort of flaked off). Your mirror may be different. Just my experience. Hope it helps.

David