I have run out of ideas. I can get the center to come to a nice sharp focus. This includes the top and bottom of the center, but the sides refuse to come into focus. I can get them to mostly come into focus by moving the screen about 2 ft forward. Even then the focus is not as sharp as it should be, but at least the image is not a collection of multiple images or a smear.

I have measured and remeasured with my micronomer and each of the four corners of the fresnels and LCD are within a few hundredths of an inch of being even (I have about 12mm of keystoning correction). As nearly as I can tell the frames are in the appropriate plane with the mirror and the rest of the box. I do not know what else to adjust, especially something which will cause a 2ft out of focus issue at the screen. The sides of the screen are equidistant from the projector, so the projector is parallel with the screen.

I have a vertical, single mirror pro lens design with a "17 LCD. The triplet is about 32" from the floor and I have 8ft ceilings. The projector is around 12ft from the screen.

on the audience left side, the focus issue is more of a smear, the center column is mostly in focus and then on the right side the focus issue is more a collection of images like a photograph of a moving image in low light. I can see several distinct images all moving in a definate direction away from the primary image.

When I figure it out I am going to feel stupid, but until then, does anyone have any ideas, please? I can provide pictures and whatever measurements you ask for.

rearden

Left focus, notice the smear
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Center focus. A nice sharp screendoor.
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Right focus, multiple images going in a definate direction.
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Try to turn your triplet around I think its facing the wrong way the lip should be on the inside

I thought the lip goes on the outside? At least that's what several plogs show.

rearden, have you checked everything from your triplet, panel, lamp and reflector. I'm guessing either one or some of these might be not paralleled with your fresnels. I'm also thinking that your lamp may not be centered with your fresnels. If I miss this then disregard.

Not on the Pro lens. The flange is on the inside with the Pro.

yep

DJ

The lip of my triplet (the new pro lens) is to the inside of the projector. I have thought about flipping it around and trying that, but I have not done it.

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The front wall of the projector has a 5deg slope to it. This is to help get the image better positioned within my ceiling and floor. The current problem is not top and bottom though, but left and right.

The triplet is mostly in the same plane of the front wall of the projector. Any amount out of adjustment should be small. But if this is extremly critical, then I can check this again.
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Simul8r, I have checked and rechecked, but that must be where the problem lies and I have missed something. I have about 20mm between lower fresnel and LCD and then between 40 and 52 mm between upper fresnel and LCD. I could use a little more keystone correction to get my sides less trapazodial, but that is much farther down the list of problems than the focus. The sides also show a little bit of bowing, as in the sides of the image on the screen do not have straight lines, but are a bit curved. I also have some dark corners which I would like a bit brighter, but I can live with.


I have been concentrating upon the fresnel/LCD combination and somewhat on the mirror and triplet. At least the triplet is in a position where it brings an image (somewhat) into focus. I have not looked at the lamp/reflector/fresnel relationship. The arc of the lamp is between 200 and 210 mm from the fresnel and is laying on the pro reflector (SD400 old style). I estimate that that should put the spherical focus of the reflector somewhere just inside of the arc tube and the plane of the "light cone" which the fresnel sees should be approximately the width of the arc tube where they intersect.

Once again, any suggestion will be considered!

Ah, your vertical, I see. Have you made sure your fs mirror is facing the triplet correctly, meaning one side might seem like a regular mirror while the other side is the actual fs.

I have, but I will quadruple check.
The blue protectant was on the side and I am reflecting off of.

The "white" on the mirror is a reflection off the tissue paper.

rearden

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There have been followups to this in my plog, but the short form is that nothing has worked so far.

More suggestions needed!

If it works you can even call me a bonehead or other derogatory names just so I have a sharp focus.

rearden

This may sound strange, but I found that when changing between the Ushio S400DD and an EYE BT28/HOR lamps changed my corner focus. I had better focus with the EYE lamp than the S400DD. I am now using the Ushio PS T15 lamp with great corner to corner focus. Is there anyway to change the position of your lamp to be perpendicular to the width of the panel ?? ... if only a temporary setup just for testing purposes... ??

... sorry this is the only advise I could muster...

cheers,
gs

hmm, that would mean quite a bit of disassebly, but I may end up having to disassemble the thing anyway. I wonder if I could use a normal lamp or other light source and see what happens.
Right now the arc is diagonal.

Is that a front surface mirror or a rear surface mirror. If it is a rear surface mirror then that is probably where your double focus on the sides are comming from.

From the images it looks like your sides sre not out of focus. It looks like they are suffering from doubling (double image). This is usually the fault of the mirror.

Edit: I see you are using the front surface mirror. Is your mirror resting on a piece of glass. That would effectively make it a rear surface mirror.

Stick with it. I think it has to be an issue with the mirror out of alignment.

40-52 mm away from the lcd? That sounds waaay too far. The farther the front frensel is from the lcd the worse the focus gets, especially in the corners. I can start to see blurred corners at 20mm.

A real stumper. I second stealthsurfers comment above - why so far between LCD and fresnel? Not saying that's the problem but why so far? And you're absolutely, positively, 100% certain that your fresnels are planar?

I just went and read the last couple of pages of your plog. This post
gave me a clue to why you may be having problems. There is also the possibility that using the pro optics in the spit mode may not work as well as the original lens set but this is just a wild guess at the moment, it should be just as effective.
So here’s the problem as I see it: your triplet’s principal plane is not parallel with the LCD. It is the same as having your triplet tilted in a straight design. Try adjusting your triplet so that it is closer to 90° to the LCD. It may even need to be slightly more to allow the triplet to resolve the virtual LCD image. Then tilt the whole box back instead of just the triplet.
I hope this is your “doh!” moment you were after. If not then it's my "Doh!" moment

DJ

I have checked the "planarity" of the fresnels nearly every time I open the thing up. They are laying in wooden frames. The bottom has some lexan on the bottom and L shaped strips screwed into the frame piniching it. The top is just laying in the frame, but I have reinforced the fresnel with the little brass "U" strips I found.

My goal was 20mm collector to LCD and 40mm LCD to field. I can reduce the LCD to field distance and see if that helps the depth of field. I can't really get any closer than 20mm though.

rearden

I investigated that last night some, but I can go down that path some more. I tilted the back up, made the front more perpendicular to the floor and then used "lens shifting" to get the image where it needed to be. It didn't seem to change things much so I put it back. I can investigate that more throughly and see what happens.

I idea was to incorporate some needed tilt into the design. I knew since the triplet high would not be at the center of the projection screen, some adjustment would necessary and Pun15her got aways with it. But his implementation is a bit better all around tha mine.

rearden