Fitting the picture

[fishlet]

I've read alot about using a stripped 14 or 15 inch monitor LCD to fit a OHP. How in the world do you get the image to fit since the light aperature on the OHP is only 11" or so?

I currently have a OHP and old projector panel but want to try stripping out a newer monitor to get better color saturation (hopefully). But I'm hesitant because it seems as if most of the edges of the LCD image are going to be lost. This seems to be a practical problem that I havn't seen discussed yet.

[18wheeler]

some OHPs ( including dukane 670, 680, elmo SD-a305, 3M 9550 etc.) have 11" stages. if you partially remove partial frame plastics you can get a full 11.75" fresnel, which is enough for 14" LCD. if you use 15" lcd, you will lost a couple of lines on the both side.

by the way, I have a 14.1" Dell LCD(already striped) and a 3m 9550 OHP that I am considering to sell in case you are interested.

[fishlet]

If you have a 11.75" fresnel and a 14" LCD... isn't there 2.25" of edge space that can't be lighted?

I guess it doesn't have to be too big a deal if you're watching a movie. The main thing I'm concerned about is launching apps from my linux start menu (it's in the bottom left corner and can easily be lopped off with a inch missing on each side of the display).

Regarding the Dell panel... how much are you asking? I'm kinda short on cash at the moment and already have a working rig (3M 9700 + Infocus 950 XGA)- just looking to get something with a bit better color saturation hopefully.

[Clinton]

OHP's are messured across and top to bottom to get the 11". LCD screens are messured diagnol to get 14,15,17"ect.. a 15" LCD is 9" X 12".

Clinton

[Guy Grotke]

Another thing to think about: If you are watching normal TV on your DIY projector, you will see a wider picture than you would on a standard analog TV. Standard TVs overscan, so they will show a picture from edge to edge. Comparing my 15" LCD projector picture to a TV, side by side, I see about 10 % more on each side on the projector screen.

So even running a 15" LCD (9" by 12") on an OHP with an 11" stage, you will still see about the same area you would on a TV.

[fishlet]

Thanks for the explanations on that... I forgot that 14" doesn't mean 14 across, but diagonal. I must have had too many dummy pills this morning

Just one more question please...

Does anyone know if I can expect the color saturation to be better If I strip out a new LCD monitor. I currently have a Infocus Powerview 950, the picture is sharp and fairly bright but the colors are all kinda dull. I've played around the contrast/color/brightness in endless variety on both the panel settings and the computer but without much improvement.

[Guy Grotke]

Older panels and many small LCDs have pretty bad contrast ratio parameters. Like 100:1. They also have slow response times around 50 msec.

If you buy even the cheapest new 15" LCD monitor, your contrast ratio will be at least 350:1. Better models have contrast ratios of 450:1 or 500:1. All have response times of 30 msec or faster.

17" LCD monitors have mostly >450:1 and <20 msec. (Later technology.)

So you can expect much better color with a new LCD monitor.

[fishlet]

Thats great news then... I'm definitely going to start watching the 'good monitors' forum to see which panel to start with.

Seeing that I'm extremely technically inept, hopefully I can find a reccomendation there on something that won't be difficult to pry apart.

Thanx for all yer help.

[18wheeler]

didn't see your post earlier. I guess you are already started to look for the 15 inchers. But I will answer your questions anyway.

I asked for $120 dollar for the Dell LCD. I ordered an 12" FFC extention cable for it 4 weeks ago, but it never came. So, if the cable is not included, I will drop price to $105 if you are interested.

since you aready have XGA panel and looking for an upgrad, this Dell will give you better contrast ratio and less blurring when there are lots of motion scenes ( assume the infocus uses older technology with 100:1 contrast, 50ms response time). But it will not match today's 15" LCDs ( at least 300:1 ratio, and 25ms response time). The benefits of using this dell are: it fits your OHP; don't need to do stripping.

so there are a couple of things you can do:

1. keep the rig. replace EVD lamp in the 9700 with a 150W CDM-T lamp. it can fit into the space nicely. the color temp is 4200K, which is far nicer than EVD's yellowish color.

cost: ~$100 ( $30-50 lamp, $40-70 ballast

2. do 1 and replace your infocus with the 14" LCD. It gives you the benefits I mentioned above. you can keep the OHP ( but need to mod a little bit to fully use the screen size)

additional cost $105 + FFC ext cable

3. buy a 15 incher and start from scratch. It's less likely you will be able to keep the 3M because the stage wont cover whole LCD.

cost: LCD: $200-300. light $30-50. ballast $50-120. fresnel: ~$35. projection lens $30 or use the one from 3M. enclosure and other material: from $0 to depends

At any case if you replace your infocus, you can pretty much get about $150- $200 on ebay since it is a such rear LCD panel with XGA resolution. 3m OHP may be $50 -100? so you can get some money back to finance your new projector.

Originally posted by fishlet

Regarding the Dell panel... how much are you asking? I'm kinda short on cash at the moment and already have a working rig (3M 9700 + Infocus 950 XGA)- just looking to get something with a bit better color saturation hopefully.

[fishlet]

Hi 18Wheeler,

Your offer for the 15" panel sounds tempting- definitely a good deal.

I'm still a bit indecisive for now so I'd say for the time being I'll pass. Ideally I would like a 14" LCD but they are not as plentiful as the 15"ers. A 14" that can be taken apart easily is probably even harder to find. I'm just passively looking at the moment, trying to accumulate a list of models that would work.

I'm trying to weigh the cons of going with a LCD that's bigger than my OHP lighting stage. For movies... it's probably no big deal- just position the media player window over the lit areas of the screen. I estimate I use it for movies 90% of the time. The remaining 10% is games... since most games are fullscreen I guess that wouldn't work out too well at all.

I havn't completely written off the idea of building one from scratch ... or more likely from a kit for my first one. It be nice if it could use the same lighting as my current OHP (400watt? FXL bulbs... their pretty cheap and the whiteness/brightness is pretty good overall). Again, I think it's just a matter of doing some more research into it first.