I have been experimenting with a some different projection lenses on for my 8.9" 1024x600LCD pj.
(AG RIP )

And Im finding that Im getting a much "cleaner" image with better color saturation using a singlet lense from a 3M overhead PJ. Carefull alignment is crucial, but I can get corner to corner focus without any percieved keystoning.

Am I able to do this because the panel is too small for "spherical abreviation" (which triplets correct right?) to be a factor?. If this reasoning is logical, it could be usefull in small pj bulids.

OR, is this the triplet I was using just dead wrong? I was using a 'Telex Video projector triplet, which was 190mm fl, 80mm diameter.
Im also getting a longer throw with this set-up. Which is nice too!

But the main thing I cant belive is how much brighter it is, and how vibrant the color looks.
The image takes on a whole new feel.... not as sharp.... but still rich and focused??? Hard to explain really.

Pics soon....

Any opinions are greatly apreciated as always,
Yosh

Pics soon....

So here is a pic of my projected image with a singlet lens,
using a 250 watt ENH(120 volt) lamp,
8.9" LCD 1024x600,

this is with sevral light leaks,

the improvment Im seeing could just be because the triplet I was using was too small. what do you think?
and as they say... it looks better in person!

Just to give an idea of the light leakage too...
this is just a "pj jig" for experiments.

One more.. same frame closer, about 5 feet from the screen.
This image is about 6' wide with the PJ lens about 10 feet away.

These pics wer taken with a FUJI finepics A345.
No tweeks!, just taken without the flash.
OH yeah, and no tripod either!

I think the combo or A/G removal and the glass singlet made for much deeper colors somehow....

I swear my triplet makes things look more yellow, which washes out the color.

this 250 watt halogen lamp has a color temp of 3200k.
That being said.. look at how deep the blue on darla's sweater is. And the flesh tones seem more acurate.

This is interesting... the image looks good from the photos. Do you know what the focal length is on your singlet lens? What model projector did it come out of?

When you say 60" in 6'. is that 60" wide. or diagonal? How close can you put the projector to the screen and still get a focused image?

Im not sure what the fl of the lens im using is. Probably somthing like 10". It came off a 3M 9050 series I think.



The image is about 6 feet wide in the pictures, with the PJ 10 feet away.

The closest I have tried the pj to the wall is 6', which gave me an image of approx. 60" wide. I wouldnt want to try it any smaller. What Im like most about this new configuration is that the screen size is just about perfect with the projector behind the viewer in a common room size. The triplet I was using (190mm fl, 80mm diameter telex from ebay) would produce an image that was too big in my opinion.

edit....
Theres no such thing as too big, but there is a such thing as too big for the room your in! ie, front row of the movie theater syndrome.

Do you still have the other triplet? I might want to buy it off you. I'm looking for something that will get big in a short throw.

Are you sure the OHP lens is a singlet? A singlet would produce chromatic aberrations in your projected image. (e.g. a bright white with dark around it like Darla's braces would show color separation, fading from red to blue in places.) Many doublet and some triplet lenses are cemented together. Look at the side of the lens for different layers of glass.

Thanks Iron Gecko,
I think your correct.

Its hard to tell, but I think it is one VERY thin singlet cemented on top of a thicker lens as you suggested

so then....
If I get a triplet with the same FL I can expect an even better picture then right?

Damn I love this place.... sniff.

Although I must admit Im tempted to "surrender" to some of the sleek designs on Allinbox. hehehehe,
I kid!, I kid!

Im sure they bust on our fat American PJ's now and again.

I would expect a triplet of the same dimensions and focal length to outperform a doublet in most cases. (Why else bother engineering one?)It's hard to know what to suggest without a before pic to compare with. I'm learning a great deal from these forums. For instance: It's important to only change one thing at a time if you want to know exactly what caused the improvement/horrid disaster. Otherwise, I'm a try-it-and-see kind of guy. I'd just fiddle with it until I found something I liked.

Same here.
Gotta get them hands dirty with real life results!

How I got to using what I thought was a singlet was through trying to make a triplet like LL member Luckyme and others,
Just using what I had laying around.

Those pics arent too shabby for 250 watt halogen thou, and again Its really the color that took me back a little.
Im used to seeing much more yellowy-whites with that bulb.

I will try to put up some comparisons, with my 190mm triplet.

maybe experienced members can help make sense of it with the math and theroy.


I really want to take my time and make this thing tiny and hella-bright. Just too bad I cant get a suitable controller for lvds 1024x600
Only way to get my G4 in there is...
svideo-to composite-to miniplug
But this is the mini, DVD movie blaster PJ, which will be a precursor to a nice 17" LL pro build.
When it comes to DVD's I surley have a clean digital signal there.
I think I can actually put a card in and play mpegs and view jpgs and such with my sdp-2500 player.

Here's a pic from the previous set-up I had with the Triplet.
190mmfl 60mm dia. TELEX 'video projector lens I got from Ebay.

This pic is also pre antiglare, and used 360 82v watt enx wired with a dimmer.
(vs the 250 watt 120v enh in the newer Darla-doublet pics)