Hi With all the hype about color filtered HD 144/145 lenses on Marquee's I was wondering if anyone could explain to me where the first lens element needs to be in relation to the tubeface to give me more focus range ?
In order to get the HD-144/145 to focus in about the middle of their adjustment range, does the first lens element need to nearer or farther from the tubeface ?
Or, how does the relationship of the tubeface to the first lens element effect the amount of focus adjustment range one has available ??

The simple answer is closer

The simple answer is closer
yeah that's the simple answer for sure. :) I got the lenses as close as possible without having the Alum. tube housing bumping into the long A-bolts and Green lense was still at the nottom of it's adjustment slot. (This was the simple adapter plates) A much more comples adapter plate could be designed but it's not really worth the expense. Having the lenses at one extreme is OK as long as your not running completely out of range.

the HD-145 lenses are designed for a CRT faceplate thickness of 0.630 inches or 16.0 mm (one specsheet says 16.5 mm though)

Kai

Could you get the lens closer to the tubeface by simply turning the scheimpfluge bolts in equally ?
I don't have enough range to defocus on both sides of where it seems the point of good focus lies, and I'm not sure there is any improvement in focus, which is why I want to be able to adjust past the point of focus both under and over in order to be SURE I've got it at the focus point.
As it stands, there is not enough range to do this...
Do the HD-145 spec sheet say how far the first lens element should be from the tubeface ?

On a NEC the lens is only about 2mm from the tube face in the rearmost focus position.

On a NEC the lens is only about 2mm from the tube face in the rearmost focus position.
Wow, that is really close...I guess I have to get the lens closer to the tubeface to regain some focus range...
The first lens element is a LOT farther from the tubeface than 2mm, even when fully to the back of its adjustment range.
Thanks for the info.

On a NEC the lens is only about 2mm from the tube face in the rearmost focus position.
Mark,

Thanks for that. I didn't mean to be flippant with my first response, but I didn't have a dimension to offer - I just know that mine would be better closer to the CRT face.

Could you get the lens closer to the tubeface by simply turning the scheimpfluge bolts in equally ?
I don't have enough range to ?
You should cut 1 loop off the spring, that helps a lot. You can use the corner of a ginding wheel, go half way through and then bend/break with pliers. There's only so far you go thoguh before the tube mount housing bumps into the long A-bolts. That's what I was trying to say above.
I thought of a way to do this without bottoming out Scheimphlug adjustment. You would first have to counter bore the 10-32 bolt heads that hold on the adapter to lenses plate so the yare flush. Then, put four .2" spacers between the adapter and original lenses plates to scoot adapter closer to tube face while leaving stock lenses plate out where they belong. I will try and post some pics this weekend and see if it works.

So I just turned the green scheimpfluge bolts all in two full turns. Now the center lens focus is in the middle of its range, and I can easily see where the point of focus is. There is enough range left on the sheimpfluge bolts too, they are still effective. I was able to get good focus all over the screen.
I turned the blue and red in 1.5 turns, with the same results. Thanks for the advice.

This might be helpful to those who are still planning to use the original Verison 1 Joust plates or making their own. I finally got some pics tonight of a small but important mod to make focusing easier with the original style lens adapters. Note: these adapters require the lenses mounting plates be removed and notched for lens clearance. Ceiling mounted machines would need to come down for this. This is NOT for the Version 2 joust plates where you trim the lenses and can be installed without removing factory lens plates.
Basically, when I installed the first set of Joust plates I found that while they move the HD145 1/2" closer to the tube face than the stock HD8's, they were still too far away. On that machine I wound up taking everything back apart and cutting the Scheimphlug springs to move lenses further back. This helped but the lenses focusing knob was still at the bottom of it's range and it was a PITA.
What I did to fix this was counter-bore the 4 original lens/adapter mounting holes so the screws weren't sticking up in the back. Then precision machine 4 Alum. spacers .2" thick to move the adapter farther back towards the tube. This works great, look at the pic, in front is the original plate and in back is the new mounting with spacers. Basically, it's equivalent to cranking the Scheimphlug bolts in 3.2 turns, which would bottom out the springs or cause tube mounting plate to hit the long A-bolts. This moves the lens in and leaves the Scheimphlug adjustment where it belongs. : )
In order to do this you will need a 3/8' counter-boring bit with 3/16ths pilot and a drill press. Also, to make the 4 small Alum. spacers a little Lathe machine is required.

Couldn't you just use a colored C-element?

Not on an air-coupled projector...

I honestly don't see any improvement in focus with HD144's over the HD8-RevB original lenses. But the colors are like when I sprayed Windex on the tubeface and stuck a $4. Roscor gel filter on the front. Somewhat nicer.

. . . . What I did to fix this was counter-bore the 4 original lens/adapter mounting holes so the screws weren't sticking up in the back. Then precision machine 4 Alum. spacers .2" thick to move the adapter farther back towards the tube. This works great, look at the pic, in front is the original plate and in back is the new mounting with spacers. Basically, it's equivalent to cranking the Scheimphlug bolts in 3.2 turns, which would bottom out the springs or cause tube mounting plate to hit the long A-bolts. This moves the lens in and leaves the Scheimphlug adjustment where it belongs. : )
. . .

Dragan,

FWIW, when I built mine, I screwed the 10-32 bolts in from the front, through the original lens plates and into the adapter plates in back.

If you do it this way, you would be able to loosen or remove the adapter plates, insert the spacers and reassemble without having to pull the PJ down from a ceiling mount.

I've been thinking about doing this, but have been busy on other theater projects.

Just an idea for those that might still be working on their own adapters.

I honestly don't see any improvement in focus with HD144's over the HD8-RevB original lenses. But the colors are like when I sprayed Windex on the tubeface and stuck a $4. Roscor gel filter on the front. Somewhat nicer. sounds like you need some help. If all you did was bottom out the Scheimphlug springs to get the lenses to focus then things must be pretty screwed up with your overall mechanical focus and lens flapping.

Dragan,
FWIW, when I built mine, I screwed the 10-32 bolts in from the front, through the original lens plates and into the adapter plates in back.If you do it this way, you would be able to loosen or remove the adapter plates, insert the spacers and reassemble without having to pull the PJ down from a ceiling mount. that's a good point Gary, if you drill out the 10-32 threads in the stock lenses plates and drill-tap the adapters instead you could bolt these in with no disassembly. It would preclude putting the HD8's back on but who would want that anyway. :)

. . . that's a good point Gary, if you drill out the 10-32 threads in the stock lenses plates and drill-tap the adapters instead you could bolt these in with no disassembly. It would preclude putting the HD8's back on but who would want that anyway. :)

No, I didn't drill mine out. I predrilled the tap holes in the back adapter plates, then clamped those plates to the back of the original lens plates. Then I ran my 10-32 tap through the front (original) lens plates and into the back adapter plates. That way I had a nice clean tap all the way through.

Now, it's going to be a little tricky getting an exact match on the threads with the spacer in between the two.

Let's see, 32 threads per inch and .20 inches is 6.4 threads, which means it's going to be a little loose, too tight, or cross-threaded. So you'd have to go with 8/32" (0.25") inch spacers or 7/32" spacers (0.21875") or 6/32" spacers (0.1875").

Do you think a 1/4" spacer is too thick?

No, I didn't drill mine out. I predrilled the tap holes in the back adapter plates, then clamped those plates to the back of the original lens plates. Then I ran my 10-32 tap through the front (original) lens plates and into the back adapter plates. That way I had a nice clean tap all the way through.
hmmm, that's pretty wacky but I guess it worked. If you want to add spacers to your existing set-up without removing the lenses plates then take the adpaters out and press fit some inserts into the back. Then Engage them from the front with 8-32 screws. Go to macmastercarr.com and check these out


Part Number: 94738A100
$7.14 per Pack of 25
Type- Knock-In Inserts for Wood and Plastics
Material Type- Steel
Internal Thread Size- 8-32
Length- .276"
Drill Size- 7/32"
Flange Thickness
.039"

I have a better solution.
Buy my New design plates. http://joustmods.com
I solved that problem.
My new design is far superior to the old in my opinion
I have been asked why my old design is no longer offered.
the reasons are:
spacing issues - the old design was difficult to get the lens close enough to the tube face on a Marquee.
Projector support - old design did not accommodate Barco or Sony
Modification difficulty level - the new design takes 30 min total to cut some soft plastic. the old took 90min of jig sawing hard, 1/2inch thick aluminum plates and difficult reinstallation of 9 stiff springs

Has anyone tried the new plates? How much spacing is there on the new version?