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Old 26th June 2002, 03:28 PM   #11
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Default Marklar...

Can you please tell me how you created a hole in your reflector big enough for the bulb base to pass through?

Also, do you have any more details for us concerning how to get a reflector like yours? I got a reflector in, but I think it might be too shallow to make efficient use of the light. Thanks.
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Old 26th June 2002, 03:54 PM   #12
Undream is offline Undream  United States
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Marklar, you punk! you do realize that we could all use a reflector like that. BTW, excellent job. Look what happens, I go on vacation, and you have to go and beat me to the final product. Oh well, I'll be finishing my box next weekend hopefully Good luck with your tweaking and perfecting. And thanks for all the great pictures of your progress. Makes me want to work more on the project! Seems like noone posts pictures except me and you Marklar .. hrmm.. come to think of it, theres not a lot of people making boxes like us, is there?
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Old 26th June 2002, 03:56 PM   #13
Jason is offline Jason  Australia
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Thanks. As I said I don't think we need any kind of in-your-face moderation, just a way to keep an eye on the ball and get stuff done when it needs to get done. I've been working hardcore on my day-job for the past 12 months, and haven't made the time to give this place the attention it needs. Now that the new site revision is done it's a lot easier for me to roll with the punches, so to speak
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Old 26th June 2002, 04:13 PM   #14
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Hi guys,
good to see you again on this new thread.
Let's continue our discussion.
Last night I made some test with fresnel panel.
As per woneill idea and from this link, which placed the fresnel panel in front of the LCD panel!
I put the fresnel 1,5" in front of the transparancy and I was surprised with the result, the projected image quality almost unchanged! there was slightly blurry at the image edge, but I think this was because my fresnel has a lot of scratched and slightly bended.
In this test, the fresnel panel doesn't act as objective lens, but as collimated lens.
If you already have 2 fresnel panel and LCD panel, you should try yourself and see the result.
The setup should go like this:
The light source should be placed at 1 fl of the first fresnel to produce parallel beam and will pass thru the LCD panel (placed right in front of it) and then hit the second fresnel panel (placed 1" to 2" in front of the LCD panel).
Light beam out from the second panel will collimate at 1 fl and at that point the objective lens should be placed.
This setup will answer one of the two LCD panel lighting conditions (another conditions is polarizing beam).

see you...
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Old 26th June 2002, 08:43 PM   #15
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Marklar,

Have you thought of using an adjustable 90 deg projection lens ,like overhead projectors, with your setup? so you could lean the box upright against a wall, out of way, and still be able to adjustment the image placement?
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Old 26th June 2002, 10:04 PM   #16
woneill is offline woneill  United States
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Hi Guys,

Good to see that the spirit lives on!

One possible downer about multiple other forums and web sites is that the previous thread acted as a single nexus for creative ideas from all over the world - some good, and some bad - but all were brought to scrutiny in one place, and while the thread was awkward to navigate, it was a single point of reference.

Anyway, back to business - there is actually a second reason I wanted to follow the LCD by a fresnel and concave lens - independent of collecting the maximum light through the LCD and maximising the contrast of it: I wanted to produce as parallel a beam as possible feeding into the main objective.

Why? To test my idea about anamorphic widescreen...

The theory is this - if you pass the beam through a concave cylindrical lens, and then subsequently pass the beam through a convex cylindrical lens of the same focal length, then in theory, the beam should be widened along one axis without disturbing the other one. With the two focal lengths of the lenses being equal, then I am hoping the overall focus of the beam will not be affected either.

Alternatively, using four cylindrical lenses (two PCV and two PCX) a configuration might be possible where the vertical axis gets compressed, while the horizontal axis gets expanded. This arrangement might be preferable because each axis gets "interfered with" less than with the single pair of lenses. Alternatively, each lens might introduce so much distortion that a less lenses is better. I honestly don't know.

I haven't tested this yet, and am waiting for my new lenses in the mail. But for this to work with the least possibility of distortion, I would guess that the more parallel the beam as it passes through this lens arrangement, the better... Hence another reason toplace a concave lens as close as is optimal to a fresnel after the panel.

I am only guessing about all this at the moment, and as I say, I have not tested it. What do you guys think?

Bill.

P.S. Gunawan, did you test the arrangement with the fresnel out on a laptop panel first to determine a rough optimal "viewpoint" for the image coming through the fresnel? This is probably very different from the optimal focal point of the objective lens. Having the actual viewpoint of the fresnel too close, or too far away can result in significant corner distortion.
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Old 27th June 2002, 01:01 AM   #17
Marklar is offline Marklar  United States
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blahn
Marklar,

Have you thought of using an adjustable 90 deg projection lens ,like overhead projectors, with your setup? so you could lean the box upright against a wall, out of way, and still be able to adjustment the image placement?

That would be what Im gonna do with beta 2, I really want to find like an old grandfather clock or something like that and cram all the stuff in there so it sits at the back of the room and looks like a peice of furniture.

HokieTT
Can you please tell me how you created a hole in your reflector big enough for the bulb base to pass through?

Also, do you have any more details for us concerning how to get a reflector like yours? I got a reflector in, but I think it might be too shallow to make efficient use of the light. Thanks.

I used an air die grinder to make the hole bigger as for making it the right size i had to find the focal point so i stick my finger in the hole umm hehe anyway i put it in there and looked stright at the reflector until the reflector turned flesh color then I measured the bulb and marked a hole then cut it.
Here is what I got the reflector off of.
Cooper Lighting
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Old 27th June 2002, 01:14 AM   #18
Marklar is offline Marklar  United States
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Default IRC

For any of you that use IRC I made a channel on dal.net #diyprojector come join and chat.
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Old 27th June 2002, 08:37 AM   #19
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has any one heard of or used the NView Spectra Pro. Its an 800x600 panel but i cant dig up any specs on it.

cheers,
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Old 27th June 2002, 08:39 AM   #20
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Default still going...

for anyone with the fuji vp5110b projection lens, i bought one from edmund for six bucks. as is, it's practically useless, but if you take it apart, there's some pretty decent lenses inside. i think this is the same one that surplus shed is selling for more money. it's got 2 pcx 1pcv and 1 dcx. i haven't made any precise measurements on them yet, but i am able to project a clear image with the convex lenses. i may try using the pcv in my light stage(before the image)
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