Hi all,

finally i got my lenses and adapters (from Bjoern) and mounted everything on my Barco Graphics 808.

Focusing works great on my screen with 2,5 meters. Distance from screen to lenses approx. 3 meters.

Today we did some more testing to go on a bigger screen 2,8 meters.
We cannot focus correctly anymore! On all lenses we are on the very outer adjustment for center and cannot make the test pattern sharp enough.

We re-installed all the lenses to be sure there's nothing wrong.
We interchanged the lenses from color to color to be sure it's not a lens prob.

What is the maximum range that HD-144 can focus on ?


Any thoughts ?


thanks for input
ElTopo

Hi Eltopo,
the first element of the 144's will need to be very close to the tube face
to focus on a large screen. If you are 2.8 meter wide, that is really pushing it.
If you are 2.8 meter diagonal, it should work - however you may need to shave
a couple mm off the spacers that are between the tubes and the mounting plate,
which will allow the lenses to be closer to the tube and achieve focus.
Be careful however not to allow the lens to touch the tube face.
With 144's you will probably be happier with a smaller screen, they were
designed for a 7" PJ and will have noticeably dimmer corners than the HD-8
or 145's when they are used on a large screen....
Hope that will help...
Galen

your throw distance is WAY too low for a 2.8m screen, and also for a 2.5m screen.

Throw ratio for these lenses should be between 1.3-1.4x screen width.

With 144's you will probably be happier with a smaller screen, they were
designed for a 7" PJ and will have noticeably dimmer corners than the HD-8
or 145's when they are used on a large screen....
Hope that will help...
Galen


Please elaborate.
HD-144 were only found on PG Xtra and XG AC PJs iirc. Both have 8" tubes, just like the PG Plus that used HD-145 lenses.
Dimensions for HD-144 and HD-145 lenses are virtually identical.

The difference in size between 7" tubes and 8" tubes is zero, it is to do with the way the companies marketed the PJ.

So that does mean i'm not able to do 2,8 m.

Why do the NEC line focus larger than 2,8m and more ?

ElTopo

With HD-144 lenses, for a 2.8m wide screen the projector should be 3.64m away from the screen.

Yes, HD-144 will do bigs screens.

But you are just too close, you might squeeze it down to 3.5m, but not 3m.

I've done all variations of distance. I only get the projector focused on about 2,5m width.

All the other are not focussable.

What's wrong with the optics ? Or the adapters ?

ElTopo

please see my post on curt's site...it might help