[Cratos]

Well I am about a week into building this thing I've been playing with the position of the lenses and light for a few days now and I cant get anything that is even watchable. At this point I really dont understand how everyone has these super bright pictures that Ive seen in the photos. I bought the guide months ago and Ive been reading the forums ever since, so I know all of the methods to get a better picture as far as making sure everything is lined up etc. At this point, I dont have a reflector but it would be impossible for a reflector to make the kind of difference this thing needs. I really cant think of anything else to do to this thing. If I move the light more than a couple of millimeters from where it is now, the picutre just gets dimmer.

-- Dan

[Cratos]

brianabs, on Aug 30 2005, 07:13 PM, said:

You will need to post some pics of the inside of the box along with pics of the image projected in order for anyone to offer up solutions. You will also need to list components used ie monitor type, bulb type, coil/eballast, etc...

<{POST_SNAPBACK}>

OK.

CMV520D
Venture puse start ed28
Venture M135/M155
LL Lense Kit

I'll go take some pics right now.

[Cratos]

OK. Here's the box. Just a standard LL design.

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[Cratos]

Another.

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[Cratos]

And some quick screen shots.

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[Cratos]

Infomercial.

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[questarthews]

It looks as if the right side of the fresnels and lcd is closer to the bulb then the left side.

I do not yet have personal experience with the pj, but unless it is just the photo, maybe that is part of your problem?

EDIT: I posted before your pics came up.

Those pics look good though, is it tv? I think I have read that tv doesn't show up so good.

This post has been edited by questarthews: 30 August 2005 - 07:57 PM

[Cratos]

And the last one.
Obviously this is just a testing setup. This room has two windows. Both of them have shades drawn and then something else covering them. Also it is raining today so the room is almost completely dark.

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This post has been edited by Cratos: 30 August 2005 - 08:02 PM

[Cratos]

questarthews, on Aug 30 2005, 07:56 PM, said:

It looks as if the right side of the fresnels and lcd is closer to the bulb then the left side.

I do not yet have personal experience with the pj, but unless it is just the photo, maybe that is part of your problem?

EDIT:  I posted before your pics came up.

Those pics look good though, is it tv?  I think I have read that tv doesn't show up so good.

<{POST_SNAPBACK}>

Naw, it is just the pics. Even so, ive tried moving them to every conceivable position.

It is tv using MythTV under linux. It looks good on my other monitor, except that the brightness is all the way up now where it was about 50% before. Even my desktop shows up very dark. That infomercial is actually a very lighted scene but you can see that it almost blends into the wall.

[davehtr]

once you get rid of the light leak and add a reflector to your setup it will get much better also your rear fresnel seems warped from the direct heat from not having tempered glass/ lexan . and where are your fans, how is your cooling setup.

[davehtr]

also painting the inside flat black with high temp paint should increase your contrast

[Cratos]

Quote

It looks like that rear fresnal is bowed pretty good. Is it bowed or is it just the picture?

The rear fresnel is bowed. That is how it came from LL. When i try to bend it straight it just pops and bows the other direction. I havnt put in the Lexan yet, but I have it.

Quote

once you get rid of the light leak and add a reflector to your setup it will get much better

The light leak at the bottom of the image? All that is is the light going over the top of the LCD. How would that make it brighter?

Quote

and where are your fans, how is your cooling setup

There are no fans yet. This is just a preliminary setup. I want to find out where everything needs to go before I finish it all up.

[SIMUL8R]

davehtr, on Aug 30 2005, 12:21 PM, said:

also painting the inside flat black with high temp paint should increase your contrast

<{POST_SNAPBACK}>

I have my light box/pyramid painted white inside with high temp automotive paint cause while experimenting with a halogen and reflection I found an even spread of light prejected to a wall, plus when I added the ushio just the inside alone of the pyramid was blinding, however, I'm still not satisfied with the amount of brilliance I'd hope. So, are you saying that perhaps I've lowered my contrast by painting the inside pyramid white that is affecting the brillance perhaps I'm looking for? Please refer to my plog to see a sample shot of what I'm projecting. Aside from the pyramid I also have a 3" diameter reflector immediately behind the ushio. My next adjustment fix will be the front fresnal since I've noticed pulling it forward made it brighter as well as exposing the triplet from it's tunnel also made it brighter, but this was from experimenting with another reflector.

[phutton]

1) Add a reflector.

2) Make sure your bulb is centered. The LCL of the Venture bulb is 5 inches. When you add the mogul base you add no more than 1/2 to 3/4 inches to that. The way it is currently set up, the inside width of the box must be between 11 to 11.5 inches for the bulb to be centered. If the inside width of the box is larger than 11 to 11.5 inches then your bulb is not centered.

3) Finally, the bulb looks quite far away from the rear fresnal. My bulb ended up about an inch or two closer than the specified amount of 220mm. I would suggest putting a drawer slider under the mogul so you can slide the bulb closer to the fresnal. This will allow you to find the best spot.

[davehtr]

well i believe on the bulb side it wont make much diffrence if its black or white as long as you dont have strey light bouncing all over the place , most people believe that the brighter the bulb side the better but thats not the case its the brighter and more concentrated the light at the focal point of the lens the brighter your projection will be.

since your fresnel is bowed you can use glass to sandwhich the fresnel to straighted it out

[davehtr]

as to the light leak making it brighter try to mask it and see the diffrence then you will know what i mean

[phutton]

Oh yeah, I would suggest a heat shield. Your fresnal is probably bowing due to too much heat hitting it. Don't let the heat shield touch the back fresnal because it gets hot.

[Cratos]

phutton, on Aug 31 2005, 04:50 AM, said:

1) Add a reflector.

Yep. I plan to. Everything is just preliminary right now.

Quote

2) Make sure your bulb is centered. The LCL of the Venture bulb is 5 inches. When you add the mogul base you add no more than 1/2 to 3/4 inches to that. The way it is currently set up, the inside width of the box must be between 11 to 11.5 inches for the bulb to be centered. If the inside width of the box is larger than 11 to 11.5 inches then your bulb is not centered.

Well my bulb/mogul base is not touching the side of the box so this does not apply. Right now it is just sitting in there on its stand, Ive moved it around to every conceivable position until it is brightest.

Quote

3) Finally, the bulb looks quite far away from the rear fresnal. My bulb ended up about an inch or two closer than the specified amount of 220mm. I would suggest putting a drawer slider under the mogul so you can slide the bulb closer to the fresnal. This will allow you to find the best spot.

Again, the light is just sitting in there so I move it around until i get it at the right position.

Next thing ill do is cut the lexan to provide a heat sheild.. see if i can get that rear fresnel straightened.

Thanks for the responses.

[phutton]

Also, make sure your bulbs are in the right position. The Ventures are NOT universal mounts. Depending on which one you got you either have to mount it vertically or horizontally. Look here for information on their mounting positions. As you can see, the ed28 comes in both types. If you happen to have the vertical mounted type and you are trying to horizontally mount it, you may be getting a much lower output.

[Cratos]

Well, I'm pretty convinced that this was a waste of my money now. Hopefully one of you can change my mind. I went out and got glass to clip the rear fresnel to so that it stays flat. that didnt really change much. It seemed to make more of the light hit the projection lense but I didnt really notice a difference in brightness.

I cant really figure out why the light isnt going into the projection lense. Both of my fresnels are flat now.

Heres a picture before the glass.

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[Cratos]

Heres with the glass on the rear fresnel.

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[Cratos]

Also, I have to have the rear fresnel tilted forward. If not, I get this rainbow looking spot in the middle of the screen. The only way to make it go away is to tilt the rear fresnel.

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