In my family room I have a 54" RCA big screen TV. 95% off all TV viewing is done through that. I've built a Beamer out of a 3M 9200 and an Ask Impact WSX projection panel. It has a native resolution of 1024x768, 30ms, 100:1.
The family room is in the basement and we watch movies in the dark on a 6' screen. I have been toying with one of 2 ideas. I was going to build a brighter projection base but I think I'm just going to buy a brighter OHP. I was also going to by an LCD monitor and take it apart. How much better will the picture be if I dismantle an LCD monitor and use it? The main deal with the contrast ratio is when your watching in a semi-lit or brighter room isn't it? The picture looks pretty darn good in the dark! I alread have a big screen for when the lights are on. I don't mind spending the extra cash if it will make a BIG improvement. What do you think?
The family room is in the basement and we watch movies in the dark on a 6' screen. I have been toying with one of 2 ideas. I was going to build a brighter projection base but I think I'm just going to buy a brighter OHP. I was also going to by an LCD monitor and take it apart. How much better will the picture be if I dismantle an LCD monitor and use it? The main deal with the contrast ratio is when your watching in a semi-lit or brighter room isn't it? The picture looks pretty darn good in the dark! I alread have a big screen for when the lights are on. I don't mind spending the extra cash if it will make a BIG improvement. What do you think?
ok first off dont buy a brighter ohp ... get a MH setup ...
second you will get a better picture with a striped lcd than a panel due to the contrast ratio .. but i dont think its worth stripping a lcd if you not gunna use a MH setup. but thats just what i think..
and dont forget a nice lens can make a big diff
second you will get a better picture with a striped lcd than a panel due to the contrast ratio .. but i dont think its worth stripping a lcd if you not gunna use a MH setup. but thats just what i think..
and dont forget a nice lens can make a big diff
I know you can ALWAYS make a better picture with more money 🙂
That's a universal truth, isn't it? I got into this because I'm . . .well . . .cheap. I also don't have a great deal of confidence in my ability to build what I thought I could. There is a lot more to lighting than I originally thought. MUCH MORE than a socket and a bulb. My luck I'd either electrocute myself or burn my house down. Neither option is very cheap.
I can get a MH overhead projector for around $200 and get somewhere in the neighborhood of 7500 lumens. Wait, stop, don't flame me. I know the Panel will eat 90% of the light. I'm just saying 7500 Lumens is better than my current 3500.
In a dark room, how much better is an LCD over the projection panel? I have a guy that will strip one for me cheap. The stripped LCD set up will just not be as pretty or as easy to work with. Just wondering if anyone had ever seen the difference between a Proj Panel and an LCD monitor and could give me an objective opinion of how much better it really looked. I KNOW it looks better, just wondered HOW MUCH better. Night and Day? Night and Early Evening? Night and Late morning? What do you guys think?
Thanks!
That's a universal truth, isn't it? I got into this because I'm . . .well . . .cheap. I also don't have a great deal of confidence in my ability to build what I thought I could. There is a lot more to lighting than I originally thought. MUCH MORE than a socket and a bulb. My luck I'd either electrocute myself or burn my house down. Neither option is very cheap.
I can get a MH overhead projector for around $200 and get somewhere in the neighborhood of 7500 lumens. Wait, stop, don't flame me. I know the Panel will eat 90% of the light. I'm just saying 7500 Lumens is better than my current 3500.
In a dark room, how much better is an LCD over the projection panel? I have a guy that will strip one for me cheap. The stripped LCD set up will just not be as pretty or as easy to work with. Just wondering if anyone had ever seen the difference between a Proj Panel and an LCD monitor and could give me an objective opinion of how much better it really looked. I KNOW it looks better, just wondered HOW MUCH better. Night and Day? Night and Early Evening? Night and Late morning? What do you guys think?
Thanks!
http://www.freewebs.com/v1d9uy/
well if you had went to my site i posted earlier you would see i had a striped lcd a vg150 on my ohp for awhile .. till my cats broke it... in my opinion unless you gunna make yer own box i wouldnt use something striped its hard to mount on the ohp..and tons of light leaks the only diff i saw between the 2 is in dark movies you can tell the diffrence between black and just dark better... with a striped lcd with the better contrast and if yer gunna spend $200 you better buy a MH setup ... and not a mh OHP 7500 lumens is nothing .. i dont think i could even watch that .. mine is 17k lumens .. and i cant watch dark movies on it now stuff like lil nemo look great .. cuz its bright ...i understand yer not great with electronics .. but fallowing a simple wireing diagram is not hard if you can read.
here is a simple ballast for cheap http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7555539480&rd=1&sspagename=STRK:MEWA:IT&rd=1
here is the bulb
http://www.atlantalightbulbs.com/ecart/10Expand.asp?ProductCode=UHI-S400DDUSHIO
33,000 lumens
5200K color temp
85 CRI
27mm arc gap
ANSI S51
20,000 hour life
combined yer out under $100 and have a way brighter bulb with alot longer life that and many peaple are useing the same ballast and bulb so wireing info is perty easy to come by
well if you had went to my site i posted earlier you would see i had a striped lcd a vg150 on my ohp for awhile .. till my cats broke it... in my opinion unless you gunna make yer own box i wouldnt use something striped its hard to mount on the ohp..and tons of light leaks the only diff i saw between the 2 is in dark movies you can tell the diffrence between black and just dark better... with a striped lcd with the better contrast and if yer gunna spend $200 you better buy a MH setup ... and not a mh OHP 7500 lumens is nothing .. i dont think i could even watch that .. mine is 17k lumens .. and i cant watch dark movies on it now stuff like lil nemo look great .. cuz its bright ...i understand yer not great with electronics .. but fallowing a simple wireing diagram is not hard if you can read.
here is a simple ballast for cheap http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7555539480&rd=1&sspagename=STRK:MEWA:IT&rd=1
here is the bulb
http://www.atlantalightbulbs.com/ecart/10Expand.asp?ProductCode=UHI-S400DDUSHIO
33,000 lumens
5200K color temp
85 CRI
27mm arc gap
ANSI S51
20,000 hour life
combined yer out under $100 and have a way brighter bulb with alot longer life that and many peaple are useing the same ballast and bulb so wireing info is perty easy to come by
OK, a little remedial lighting. And yes, I have been reading. Thats the only reason I THINK I know what I'm getting ready to type.
I like the idea of putting a MH setup. I always have. I looked at the base of my OHP and it looks very simple. Its a box, a light, a fan, and a mirror.
The top looks like it would be VERY easy to remove. 4 screws mount the hinge to the side. The Arm that houses the triplet lens and mirror has only 2 screws. If I make a simple box that contains the light, the ballast and a fan I think I would be able to mount the top of my OHP and the arm with the lens and mirror on it.
I will need to mount the bulb directly under the base fresnel lens with some kind of reflector to direct the most of the light upwards toward the lense. Its the job of the fresnel lense to disperse the light evenly, correct? With a light that bright won't I need to make the base deeper to avoid hot spots? Is there a calculation for how deep or did I miss that in my reading? Ideally I would just use the current base and mount the ballast outside but I think the stck fan would be a little weak. What about the heat and extra light on the stock lenses? Too much for them?
Sorry about all the questions. I am trying though. Just not very confident in my abilities right now.
I like the idea of putting a MH setup. I always have. I looked at the base of my OHP and it looks very simple. Its a box, a light, a fan, and a mirror.
The top looks like it would be VERY easy to remove. 4 screws mount the hinge to the side. The Arm that houses the triplet lens and mirror has only 2 screws. If I make a simple box that contains the light, the ballast and a fan I think I would be able to mount the top of my OHP and the arm with the lens and mirror on it.
I will need to mount the bulb directly under the base fresnel lens with some kind of reflector to direct the most of the light upwards toward the lense. Its the job of the fresnel lense to disperse the light evenly, correct? With a light that bright won't I need to make the base deeper to avoid hot spots? Is there a calculation for how deep or did I miss that in my reading? Ideally I would just use the current base and mount the ballast outside but I think the stck fan would be a little weak. What about the heat and extra light on the stock lenses? Too much for them?
Sorry about all the questions. I am trying though. Just not very confident in my abilities right now.
fresnels
The main job of your fresnels is to direct most of the light into the projection lens. To do that, the MH lamp arc will have to go exactly where the current OHP filament sits. You might have to strip out some of the guts inside the box, to get the MH lamp where it needs to go. Ballast and fan(s) mounted outside the box are both possible. You just fabricate additional little boxes for them.
Another issue is that LCD monitor panels tend to have a diffuser layer on the front of the screen to cut glare and improve the viewing angle. So you might get more light leaking off the LCD. Some people build a cone between the stage area and the lens, to cut some of this light leakage.
I would not worry about heat too much: A 400 Watt MH lamp puts out a lot less heat than a 360 Watt tungsten halide OHP lamp. And it puts out around 33000 lumens!
The main job of your fresnels is to direct most of the light into the projection lens. To do that, the MH lamp arc will have to go exactly where the current OHP filament sits. You might have to strip out some of the guts inside the box, to get the MH lamp where it needs to go. Ballast and fan(s) mounted outside the box are both possible. You just fabricate additional little boxes for them.
Another issue is that LCD monitor panels tend to have a diffuser layer on the front of the screen to cut glare and improve the viewing angle. So you might get more light leaking off the LCD. Some people build a cone between the stage area and the lens, to cut some of this light leakage.
I would not worry about heat too much: A 400 Watt MH lamp puts out a lot less heat than a 360 Watt tungsten halide OHP lamp. And it puts out around 33000 lumens!
FYI
Sorry to butt in but.. just something that I think might help a bit. A projector such as the Dukane 680 is rated at 8,000 lumens. This projector uses a 575 watt MH bulb. Now, I am not totally sure how the actuall projected lumens are measured or whatever... but to get to the point, that 575 watt bulb is rated at 49,000 lumens. You guys had me thinking that your 400 watt bulb was ungodly bright for a minute. I'm glad I did my homework. 😛
Item: Osram Lamp 54098
Avg Life: 750
K Temp: 6000
Lumens: 49000
Sorry to butt in but.. just something that I think might help a bit. A projector such as the Dukane 680 is rated at 8,000 lumens. This projector uses a 575 watt MH bulb. Now, I am not totally sure how the actuall projected lumens are measured or whatever... but to get to the point, that 575 watt bulb is rated at 49,000 lumens. You guys had me thinking that your 400 watt bulb was ungodly bright for a minute. I'm glad I did my homework. 😛
Item: Osram Lamp 54098
Avg Life: 750
K Temp: 6000
Lumens: 49000
yer bulb is brighter ..... ya ...but its hotter and has alot less life .. that and the color temp is off
ushio ss400d = 33,000 lumens
20,000 hour life
5,200k color temp
$37.95 - $50 + shipping
ushio ss400d = 33,000 lumens
20,000 hour life
5,200k color temp
$37.95 - $50 + shipping
Ok everyone . . . I whimped out. I just don't have the time or money to dedicate to something I'm not sure will work. Rather than gut my existing projector or try to build a base out of wood I just bought a MH projector. Elmo 305SD Solar Metal Halide with 7700 Lumens projected. It will be here in about a week. From what I've read it uses a 575W Double Ended MH bulb. Can anyone confirm that and tell me where to get them? It sounds like the same bulb your using Jiggly. I've called 3 bulb companies and no one has them.
I know the whole point of projection is a BIG screen but I don;t need anything larger than 72". I figure the 7700 Lumes (770 after the panel probably) on a 72" screen should be pretty bright. The 750 Hour life may seem short to some of you but I have 2 kids age 4 and 5. We have 2 family movie nights per week. Thats over 3 years worth of movies!
Sorry to let you down v1d9uy. I know you advised against a brighter OHP but I just don't see as I have much of an option.
Back to my original question. Wouldn't the contrast ratio also come more into play when dealing with less light or a bigger screen? A lot of people have reported good results with a QA-1650. They sure sell well on eBay and their contrast ratio is only 60:1. What gives?
I know the whole point of projection is a BIG screen but I don;t need anything larger than 72". I figure the 7700 Lumes (770 after the panel probably) on a 72" screen should be pretty bright. The 750 Hour life may seem short to some of you but I have 2 kids age 4 and 5. We have 2 family movie nights per week. Thats over 3 years worth of movies!
Sorry to let you down v1d9uy. I know you advised against a brighter OHP but I just don't see as I have much of an option.
Back to my original question. Wouldn't the contrast ratio also come more into play when dealing with less light or a bigger screen? A lot of people have reported good results with a QA-1650. They sure sell well on eBay and their contrast ratio is only 60:1. What gives?
i dunno man if its just for personal kid movies .. and yer not gunna really get into it a 1650 is prolly fine ..... but i would sugest a 1800 they are more rare ... and i watch ebay ALOT but im sure you could find one for a decent price but make dam sure they have good feedback ..... and garantee it to work or money back trust me its worth paying more for one thats garanteed to work if you cant find anything .. i may sell mine and strip a lcd after i spend hours on ebay trying to find a decent stripable lcd for a decent price... my sharp is like brand new .. really no scratches dings anything i even got the original box. it still even has the plastic covering the sensor for the remote .... lol check here for panel specs
http://www.freewebs.com/v1d9uy/ohppanelspecslist.htm
http://www.freewebs.com/v1d9uy/ohppanelspecslist.htm
I've got an Ask Impact WSX that does 1024x768, 16mill colors and a contrast ration of 100:1. My only point was this. . .
People are tearing apart LCD monitors to get 450:1 contrast ratios. That's great if you can do it and can make a box that looks good. But I've seen post where people say something like "It only has a contrast ratio of 250:1, that's almost unwatchable" . . .Huh? How can one group be thrilled with a QA-1650 that is 60:1 and another claim that 250:1 is horrible? i want the best picture i can get, just not at the expense of a tangle of wires, 4 case fans, and a bunch of noise sitting on top of my OHP.
So where is the cut-off? Is 60:1 OK if your under 8' and bright? Is 100:1 noticeably better than 60:1. I don't understand. I know what the contrast ratio does, just not under which circumstances it is most important.
People are tearing apart LCD monitors to get 450:1 contrast ratios. That's great if you can do it and can make a box that looks good. But I've seen post where people say something like "It only has a contrast ratio of 250:1, that's almost unwatchable" . . .Huh? How can one group be thrilled with a QA-1650 that is 60:1 and another claim that 250:1 is horrible? i want the best picture i can get, just not at the expense of a tangle of wires, 4 case fans, and a bunch of noise sitting on top of my OHP.
So where is the cut-off? Is 60:1 OK if your under 8' and bright? Is 100:1 noticeably better than 60:1. I don't understand. I know what the contrast ratio does, just not under which circumstances it is most important.
i think the contrast ratio is most important while watching dark movies and as far as some peaple being thrilled with 100:1 and other saying 250 is watchable ..... everyone expects something diff some have high expectations and others are just so happy they have a 120inch screen they dont care if its not perfect
i am perty happy with my panel even with the 800x600 and the 100:1 ratio... but id be alot happier if it were brighter. also peaple get pissy and say that 30-40 ms response time is really bad .. and thats a load of BS cuz my panel is prolly only 50ms respnse time and i played counterstrike and doom3 on yet .. and it was great didnt notice ghosting or anything ... granted i do have a perty good video card so that might help but how much im not sure also some peaple just cant help compairing there $2000 projector to the one they just built for $200 .... and saying its bad .. but for what you put into it .. its perty dang good.
i am perty happy with my panel even with the 800x600 and the 100:1 ratio... but id be alot happier if it were brighter. also peaple get pissy and say that 30-40 ms response time is really bad .. and thats a load of BS cuz my panel is prolly only 50ms respnse time and i played counterstrike and doom3 on yet .. and it was great didnt notice ghosting or anything ... granted i do have a perty good video card so that might help but how much im not sure also some peaple just cant help compairing there $2000 projector to the one they just built for $200 .... and saying its bad .. but for what you put into it .. its perty dang good.
contrast ratio
I measure 277:1 with my 15" Proview-based projector. But that does not matter at all if you have any light leaking onto the screen. You don't even need to have another light on in your house: The light coming off the screen image gets reflected back off your walls to wash out the darkest areas of your image.
So if you are a contrast fanatic, then you need dark curtains all around the walls of your home theatre!
But I think this would be like guys who NEED gold-plated speaker wire as big around as their thumb, in order to enjoy their stereo. Lots of people have enjoyed big screen TV with contrast ratios under 100:1 for years. It only makes a difference during dark scenes, and I figure that if the director wanted you to be able to see them clearly then they would have added more light!
As for 800 by 600: It just means the screendoor pattern will be visible from 5 feet instead of 4 feet. Doesn't matter at all if you sit 8 feet away. Especially if your video source is not HDTV. Even progressive scan DVD players do only 640 by 480.
I measure 277:1 with my 15" Proview-based projector. But that does not matter at all if you have any light leaking onto the screen. You don't even need to have another light on in your house: The light coming off the screen image gets reflected back off your walls to wash out the darkest areas of your image.
So if you are a contrast fanatic, then you need dark curtains all around the walls of your home theatre!
But I think this would be like guys who NEED gold-plated speaker wire as big around as their thumb, in order to enjoy their stereo. Lots of people have enjoyed big screen TV with contrast ratios under 100:1 for years. It only makes a difference during dark scenes, and I figure that if the director wanted you to be able to see them clearly then they would have added more light!
As for 800 by 600: It just means the screendoor pattern will be visible from 5 feet instead of 4 feet. Doesn't matter at all if you sit 8 feet away. Especially if your video source is not HDTV. Even progressive scan DVD players do only 640 by 480.
"I figure that if the director wanted you to be able to see them clearly then they would have added more light!" I love that line!
Great, I never thought about it that way. The projector can't shine a black light on the screen, for black it just blocks the light. My projection room is in my basement and we will be watching movies in the dark. If you can control the ambient lighting to that extent then the contrast ratio won't be nearly as noticableI would imagine.
Also answers another question that I had asked. You said that people had been enjoying comtrast ratios less than 100:1 on big screen TVs for years. I remember when big screens first came out the picture was terrible at anything less than about 10'. Do you know what the normal contrast ratio was for a rear-projection big screen in 1999 when I bought my RCA?
Thanks
Great, I never thought about it that way. The projector can't shine a black light on the screen, for black it just blocks the light. My projection room is in my basement and we will be watching movies in the dark. If you can control the ambient lighting to that extent then the contrast ratio won't be nearly as noticableI would imagine.
Also answers another question that I had asked. You said that people had been enjoying comtrast ratios less than 100:1 on big screen TVs for years. I remember when big screens first came out the picture was terrible at anything less than about 10'. Do you know what the normal contrast ratio was for a rear-projection big screen in 1999 when I bought my RCA?
Thanks
One more thing, You said a progressive scan DVD player outputs 640x480. I thought DVD resolution was 720x480.
video resolution
Horizontal resolution is hardly ever mentioned when it comes to TVs and video recording technology. That is because they don't really want you to know just how bad it is.
NTSC Standard TV can show you 320 different colored pixels on each horizontal line, but they overscan the edges of the tube by 15-20%, so you really only see 256-272 pixels!
The "spec" for NTSC is 488 horizontal lines, but it is really half that with alternating frames interlaced. They also overscan vertically, so 320 by 240 is what you are really watching.
A standard DVD contains enough data to give you non-interlaced video with about 480 horizontal lines. That is 480i. It can generate 720 pixels per line, but that depends on the interface you use.
If you watch this on a standard TV using a composite video or RF interface, then you will still see 256-272 horizontal pixels. If you use an 800 by 600 video projector to watch composite video, then it will up-sample it to generate 800 by 600 pixels but the source resolution will still be only 320 by 480.
You have to use an S-Video interface to get more pixel data to your projector. Or use component video which is even better.
Horizontal resolution is hardly ever mentioned when it comes to TVs and video recording technology. That is because they don't really want you to know just how bad it is.
NTSC Standard TV can show you 320 different colored pixels on each horizontal line, but they overscan the edges of the tube by 15-20%, so you really only see 256-272 pixels!
The "spec" for NTSC is 488 horizontal lines, but it is really half that with alternating frames interlaced. They also overscan vertically, so 320 by 240 is what you are really watching.
A standard DVD contains enough data to give you non-interlaced video with about 480 horizontal lines. That is 480i. It can generate 720 pixels per line, but that depends on the interface you use.
If you watch this on a standard TV using a composite video or RF interface, then you will still see 256-272 horizontal pixels. If you use an 800 by 600 video projector to watch composite video, then it will up-sample it to generate 800 by 600 pixels but the source resolution will still be only 320 by 480.
You have to use an S-Video interface to get more pixel data to your projector. Or use component video which is even better.
Here is an explanation of TV resolution:
http://www.maxim-ic.com/appnotes.cfm/appnote_number/750
According to these, there are 451 active horizontal pixels for NTSC, or 538 for PAL, and this is due to limited bandwidth, as the TV signal is not digital and there are no strictly defined "pixels".
Interlacing is not an issue for the purpose of our projectors, as LCD always requires signal to be deinterlaced before reaching display device.
Regards
http://www.maxim-ic.com/appnotes.cfm/appnote_number/750
According to these, there are 451 active horizontal pixels for NTSC, or 538 for PAL, and this is due to limited bandwidth, as the TV signal is not digital and there are no strictly defined "pixels".
Interlacing is not an issue for the purpose of our projectors, as LCD always requires signal to be deinterlaced before reaching display device.
Regards
OK, let me get this straight then. If you connect a projection panel to the rca video out from a DVD player or to the RCA output from a VCR as a TV tuner then a 640X480 panel like the QA-1650 will be as good as the Ask Impact WSX that is 1024x768. The only difference being the screen-door effect will be more noticeable on the 1650. That will be a non-issue if you sit 8' or more away from the screen anyway. Is that right?
There is another reason why nobody would want to use such a low contrast LCD, like 100:1 or so. Due to a pitiful light output, everybody will try to tweak LCD setting to make it "more transparent", to get more visible screen contents. And this process of "making LCD transparent" (gamma correction and other settings) can be done only at cost of real contrast ratio, as this is basically "squeezing" high tonal range of input image into low upper range of LCD colour tones. So, having a 400:1 LCD we sqeeze the brightness levels maybe into upper 100:1 range, and it's still kinda watchable. But doing the same with a 100:1 panel would lead to 25:1 final contrast ratio on the screen, and your friends will laugh on you when you present them such "results" 🙂
Regards
Regards
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