green? No...my camera sucks
OK OK...so the pictures look green. It is due to my camera. As I mentioned a few pages back (and Fender just reiterated) this buld produces a very bright light that has a slight blue appearence. The camera I have sucks and the image turned out green for some reason....sorry.
Fender... thanks for info about the reflector but I already new about that becuase I had to screw the reflector on. I would like to be able to remove the plastic cylinder from the reflector without breaking the plastic or bending(or unbending i guess) the reflector. OH! and I too definitely agree that a proper reflector is key. We need to figure something out here. An elipitcal reflector would be ideal but is probably the least likey to get I would think. If I can just get something to focus the light toward the fresnel (kinda like in the OHP) I would be happy because I would just use another fresnel to focus the light into my lens.
I saw some worklights(kinda like drop lights) at home depot that had large spherical aluminum reflector attached. I was thinking of getting one of these and trying it to see if I could send most of the light into the fresnel....hell I was even thinkging of buying a an aluminum mixing bowl and drilling a hole in the middle...If it worked good enough I would polish it up (now that would be funny but might actually work as a temporary solution).
frankbatzen...I am confused by your statement a little. You say I need a blind to make it more point-like. I thought that my bulb was basically a point source...Fender isnt it???....am I missing something?
OK OK...so the pictures look green. It is due to my camera. As I mentioned a few pages back (and Fender just reiterated) this buld produces a very bright light that has a slight blue appearence. The camera I have sucks and the image turned out green for some reason....sorry.
Fender... thanks for info about the reflector but I already new about that becuase I had to screw the reflector on. I would like to be able to remove the plastic cylinder from the reflector without breaking the plastic or bending(or unbending i guess) the reflector. OH! and I too definitely agree that a proper reflector is key. We need to figure something out here. An elipitcal reflector would be ideal but is probably the least likey to get I would think. If I can just get something to focus the light toward the fresnel (kinda like in the OHP) I would be happy because I would just use another fresnel to focus the light into my lens.
I saw some worklights(kinda like drop lights) at home depot that had large spherical aluminum reflector attached. I was thinking of getting one of these and trying it to see if I could send most of the light into the fresnel....hell I was even thinkging of buying a an aluminum mixing bowl and drilling a hole in the middle...If it worked good enough I would polish it up (now that would be funny but might actually work as a temporary solution).
frankbatzen...I am confused by your statement a little. You say I need a blind to make it more point-like. I thought that my bulb was basically a point source...Fender isnt it???....am I missing something?
For those with the infocus 820 panels...
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1727657238
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1727657238
Fender;
But did you see the size of the thing? And the parabolic/elliptic reflector inside? I thought they said they had bulbs as well...
But did you see the size of the thing? And the parabolic/elliptic reflector inside? I thought they said they had bulbs as well...
Whoa! That pic didn't load last time. That thing is huge. That reflector might be nice, but damn. I also can't tell what kind of socket that is, but it doesn't look like a Mogul. Hmmm.
I'm with you, Superdave. I've thought about trying anything shaped like a parabola...maybe we'll get lucky. When I get a chance, I might wander through Home Depot, Wal-mart, Target, etc. to see what could possibly be solution. If it came down to it, you could probably make a mold (clay? wood?) with some careful math and measurements and use that to make a reflector out of something 😕 ?!? I think Myren may have mentioned this approach a few months ago. If you have a short throw PCX or DCX lens, try using that between the bulb and the fresnel. That helped my setup, even without a reflector.
I think the point-source description is relative...you want the source to be as small as possible while producing the appropriate intensity. The MV bulb "filament" is larger than most OHP bulbs I have seen, but it is MUCH closer to a point source than, say, a fluorescent bulb. It's not perfect, but probably useful. Frankbatzen's "blind" idea makes sense in that it only lets parallel (or close to parallel) light through causing less scatter and "washing out". But you are still losing a HUGE amount of light to places other than the LCD...especially with the large-envelope MV bulbs. Is this right, frankbatzen?
OK. I've met my post quota for the day. I'll be quiet now. 😎
-f4
I'm with you, Superdave. I've thought about trying anything shaped like a parabola...maybe we'll get lucky. When I get a chance, I might wander through Home Depot, Wal-mart, Target, etc. to see what could possibly be solution. If it came down to it, you could probably make a mold (clay? wood?) with some careful math and measurements and use that to make a reflector out of something 😕 ?!? I think Myren may have mentioned this approach a few months ago. If you have a short throw PCX or DCX lens, try using that between the bulb and the fresnel. That helped my setup, even without a reflector.
I think the point-source description is relative...you want the source to be as small as possible while producing the appropriate intensity. The MV bulb "filament" is larger than most OHP bulbs I have seen, but it is MUCH closer to a point source than, say, a fluorescent bulb. It's not perfect, but probably useful. Frankbatzen's "blind" idea makes sense in that it only lets parallel (or close to parallel) light through causing less scatter and "washing out". But you are still losing a HUGE amount of light to places other than the LCD...especially with the large-envelope MV bulbs. Is this right, frankbatzen?
OK. I've met my post quota for the day. I'll be quiet now. 😎
-f4
spherical reflector
It's funny you mention molding your own reflector...I have been looking for one and started thinking I might make my own.
I just dont know what material to use? I'm thinking hell...I can go buy a plastic ball from the grocery store (you know those ones in the big basket that the kids always play with). If I find the proper maaterial I could mold it over 1/2 the ball to form my reflector. I would then need to find out how to make it reflective...I wonder if the "chrome metal" looking spray paint would work and still be safe.
Anybody have ideas on this... If anyone can suggest material that will be safe and cheap I will give it a try...We need to find something that will work. I'm telling you though...if I dont get any better suggestions I AM going to go buy a metal mixing bowl and try that.
So...what can I use to safely mold a reflector. And what can I safely use to make if reflective?
I too have probably met my posting quota for the day unless anyone asks me questions I will lay off for at least a day...maybe two.
Dave
It's funny you mention molding your own reflector...I have been looking for one and started thinking I might make my own.
I just dont know what material to use? I'm thinking hell...I can go buy a plastic ball from the grocery store (you know those ones in the big basket that the kids always play with). If I find the proper maaterial I could mold it over 1/2 the ball to form my reflector. I would then need to find out how to make it reflective...I wonder if the "chrome metal" looking spray paint would work and still be safe.
Anybody have ideas on this... If anyone can suggest material that will be safe and cheap I will give it a try...We need to find something that will work. I'm telling you though...if I dont get any better suggestions I AM going to go buy a metal mixing bowl and try that.
So...what can I use to safely mold a reflector. And what can I safely use to make if reflective?
I too have probably met my posting quota for the day unless anyone asks me questions I will lay off for at least a day...maybe two.
Dave
just a quick note to all, if you take apart your gear carefully, and you end up ****ing something up like i did (ripped off a ribbon cable in a hardcore manner), you can put it nicely back together and ship it back to the manufactuer. like i did. and they'll nicely send you a new one.
taking apart a multi-hundred dollar piece of gear is a teeth gnawing experience not for everyone.
the reflector is no trivial task. i'm dealing with a number of different metal workers to get the things custom built. its not fun. i'm sure theres some DIY way. theres got to be.
if we could make a decent reflector DIY though, the payoffs would be huge. If you make the reflector wider than the panel. you can just put the panel in front of the reflector and the light automagically focuses itself through the panel down to a point. as an added bonus, it has perfect light uniformity. the image is all constant brightness. with something like a fresnel, the edges are a little bit darker than the center.
as for the cinema systems, theres definately a lot of potential for that too. the short arc systems are definately a possibility, but the efficiency is pretty crap. theres some really nice 1000 and 2000 watt metal halides that should provide upwards of 300,000 lumens. much cooler, much more efficient. and way better cost effectivity. $70 bulb v. $2000 bulb for xenon short arc. and it lasts 20,000 hours.
myren
taking apart a multi-hundred dollar piece of gear is a teeth gnawing experience not for everyone.
the reflector is no trivial task. i'm dealing with a number of different metal workers to get the things custom built. its not fun. i'm sure theres some DIY way. theres got to be.
if we could make a decent reflector DIY though, the payoffs would be huge. If you make the reflector wider than the panel. you can just put the panel in front of the reflector and the light automagically focuses itself through the panel down to a point. as an added bonus, it has perfect light uniformity. the image is all constant brightness. with something like a fresnel, the edges are a little bit darker than the center.
as for the cinema systems, theres definately a lot of potential for that too. the short arc systems are definately a possibility, but the efficiency is pretty crap. theres some really nice 1000 and 2000 watt metal halides that should provide upwards of 300,000 lumens. much cooler, much more efficient. and way better cost effectivity. $70 bulb v. $2000 bulb for xenon short arc. and it lasts 20,000 hours.
myren
Heres an interesting link. No picture, but, description --- It seems to be another possibility for a projection lens. Might work great if you had a 5" LCD, which can be found a lot easier than a 2 or 3" one! Its 39.95 though, quite a bit more than a Delta from surplusshed.
Possible Lens /w diameter over 5"
Possible Lens /w diameter over 5"
Reflectors
I'm not sure if this would be useful at all, but this link is for a 95mm concave mirror, it doesnt state wether the mirror is spherical or not, this site does have spherical mirrors but they are small 50mm ones with varying fl's.
I am now officially a thread hobo, squatting here and contributing nothing at the moment, thats the price of being a final year student. That along with the girlfriend means I've got no money for the important things in life like HiFi and DIY.
Keep working, as soon as I've finished i'm selling my tv, projector and some of my camera stuff to get going again.
Nick.
I'm not sure if this would be useful at all, but this link is for a 95mm concave mirror, it doesnt state wether the mirror is spherical or not, this site does have spherical mirrors but they are small 50mm ones with varying fl's.
I am now officially a thread hobo, squatting here and contributing nothing at the moment, thats the price of being a final year student. That along with the girlfriend means I've got no money for the important things in life like HiFi and DIY.
Keep working, as soon as I've finished i'm selling my tv, projector and some of my camera stuff to get going again.
Nick.
More panel reviews coming soon! Help with Pics??
Just recieved two LCD projector panels, the Nview z310 (1024x768) and a Infocus 950 (also 1024x768) The 950 already got poor reviews by Joe, but I'm interested to see if maybe he got a bad panel (although vauge reviews by Macworld years ago yielded the same result: really bad colors on video input). I have a infocus PV 820 coming soon as well, can't wait to try out its vga input. BTW, I'm borrowing a friends Apollo OHP (damn, its nice and SUPER quiet, but more on that later...)
My question is how the heck can I take decent pictures. I'm in the market for a new digital camera, what features should I look for? And which ones should I avoid that deliver poor color at low light? I'm assuming I'm looking for one that has a fast lense. Do I need one with manuel shutter settings (for tripod action). Seems like you pay a lot of $$ for shutter controls...
I'm also heading over to Home Depot today to get the Parkland Plas-tex thing, couldn't stand my textured off-white wall, it was giving me head ache after only 30 min, hope it was that and not the 75 hz refresh rate that was causing me problems.
Just recieved two LCD projector panels, the Nview z310 (1024x768) and a Infocus 950 (also 1024x768) The 950 already got poor reviews by Joe, but I'm interested to see if maybe he got a bad panel (although vauge reviews by Macworld years ago yielded the same result: really bad colors on video input). I have a infocus PV 820 coming soon as well, can't wait to try out its vga input. BTW, I'm borrowing a friends Apollo OHP (damn, its nice and SUPER quiet, but more on that later...)
My question is how the heck can I take decent pictures. I'm in the market for a new digital camera, what features should I look for? And which ones should I avoid that deliver poor color at low light? I'm assuming I'm looking for one that has a fast lense. Do I need one with manuel shutter settings (for tripod action). Seems like you pay a lot of $$ for shutter controls...
I'm also heading over to Home Depot today to get the Parkland Plas-tex thing, couldn't stand my textured off-white wall, it was giving me head ache after only 30 min, hope it was that and not the 75 hz refresh rate that was causing me problems.
what's this?
anyone know what this is exactly???
http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=1725561574
tried emailing the seller twice, but never got any response.
anyone know what this is exactly???
http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=1725561574
tried emailing the seller twice, but never got any response.
I hate dial up. Earthlink goofed, disconnected my dsl. I get home today from home depot, with my new MV light, and dial up to find Superdave has the same light, and it pretty much sucks. I was using a halogen worklight (way too hot) and getting a decent picture with its 8500 lumens. The MV claims 7000 lumens, and i retooled my case for it, and see now that it is worthless. My advice to anyone thinking of Metal Halide, Mecury Vapor, or High pressure sodium is to not even bother with anything less than 250 Watts. Good thing i have my Depot reciept. (darn, the plastic cover was Broken when i got it!!)
Digital Camera.
Contrapasta.
When you buy a digital camera, buy one with the most pixels and the largest overall range of shutter speeds. If you want it to take good pictures of the results of projection then you'll need to be able to mount it on a tripod, turn off the Flash (extremely useful anyway as the prediction systems in these cameras are usually crap) and take very long exposures.
The lenses don't seem to make much difference unless your spending mucho dollars.
And the biggest fact in my opinion is BATTERY LIFE. Whats the point of having this great camera if you need to change the batteries every 15 minutes.
Enjoy.
Nick
Contrapasta.
When you buy a digital camera, buy one with the most pixels and the largest overall range of shutter speeds. If you want it to take good pictures of the results of projection then you'll need to be able to mount it on a tripod, turn off the Flash (extremely useful anyway as the prediction systems in these cameras are usually crap) and take very long exposures.
The lenses don't seem to make much difference unless your spending mucho dollars.
And the biggest fact in my opinion is BATTERY LIFE. Whats the point of having this great camera if you need to change the batteries every 15 minutes.
Enjoy.
Nick
oftheend...I wouldnt say it is totally worthless...it's just a matter of being able to reflect the light properly. This is proving to be quite difficult for me. Thats funny about the plastic cover being broken...mine was all cracked when I bought mine.
I did go out last night in search of something to use as a reflector. I bought a drop light with reflector that turned out to be to small...I bought a halogen light and tried the reflector in it...didnt work well....and I did it...I bought a mixing bowl(I think it was actually a punch bowl).
I was at WalMart and found an outstanding mostly-spherical and large bowl to try as a reflector. This was made out of highly polished stainless steal. I could see my reflection quite well in it and thought it was worth a shot for a whopping $5 (couldn't believe it was only $5). Well I drilled out a 1.5 inch hole in the center and mounted it to my light. It did work A LOT better than having no reflector but I still could not get the light too focused. This produced a much brighter image but still nothing close to what I would expect a 7K lumen light to produce.
A word of caution for anyone building a reflector. I think I got pretty lucky last night that I built the GFI box I mentioned a few pages back. I was moving the stainless steel reflector around and it somehow slipped and made contact with metal base of the bulb while I was holding it. This caused the GFI to immediately switch off and save me from QUITE A KICK IN THE ***. At least I assume so. I dont really know how conductive stainless steal is but I am pretty sure if it caused the GFI to short out then I probably got lucky. I would DEFINITELY suggest anyone doing stuff like this to buy or build one of these for you own protection.
Later...
Dave
I did go out last night in search of something to use as a reflector. I bought a drop light with reflector that turned out to be to small...I bought a halogen light and tried the reflector in it...didnt work well....and I did it...I bought a mixing bowl(I think it was actually a punch bowl).
I was at WalMart and found an outstanding mostly-spherical and large bowl to try as a reflector. This was made out of highly polished stainless steal. I could see my reflection quite well in it and thought it was worth a shot for a whopping $5 (couldn't believe it was only $5). Well I drilled out a 1.5 inch hole in the center and mounted it to my light. It did work A LOT better than having no reflector but I still could not get the light too focused. This produced a much brighter image but still nothing close to what I would expect a 7K lumen light to produce.
A word of caution for anyone building a reflector. I think I got pretty lucky last night that I built the GFI box I mentioned a few pages back. I was moving the stainless steel reflector around and it somehow slipped and made contact with metal base of the bulb while I was holding it. This caused the GFI to immediately switch off and save me from QUITE A KICK IN THE ***. At least I assume so. I dont really know how conductive stainless steal is but I am pretty sure if it caused the GFI to short out then I probably got lucky. I would DEFINITELY suggest anyone doing stuff like this to buy or build one of these for you own protection.
Later...
Dave
Superdave, how can you built a projector without knowledge of optical parameters. There's a relation between focal lenght distance and size of all this elemnts.It isn't that simple, that you have free choice with all this lenses bulbs and reflectors, because the size of LCD-panel is a fix parameter. You have to built a projector around this. So you have to calculate the focal lenght of your reflector, if you don't wanna go the OHP-like route.
On your pics i noticed a Fender Stratocaster and i asume you play it. I would say it's the same with music, i'm a guitarplayer too. The shape of guitar and strings are fixed parameters. You must know something about chords and scales to play good! And so you must do building a projector. I think it's better to make drawings of lightpaths and distances BEFORE you buy ANY bulbs, reflectors and lenses or this will be LOW-LEVEL engeneering! With a lot of costs and bad results..
I don't wanna kill enthusiasm here !
cheers
xblocker
On your pics i noticed a Fender Stratocaster and i asume you play it. I would say it's the same with music, i'm a guitarplayer too. The shape of guitar and strings are fixed parameters. You must know something about chords and scales to play good! And so you must do building a projector. I think it's better to make drawings of lightpaths and distances BEFORE you buy ANY bulbs, reflectors and lenses or this will be LOW-LEVEL engeneering! With a lot of costs and bad results..
I don't wanna kill enthusiasm here !
cheers
xblocker
Point sources versus Diffusive sources
First it was LOA, a diffusive light source, then there was a lot of debate on the need for a point light source . Now, within the last 24 hours we have a revival of parabolic reflectors which IMHO takes us right back to diffusive light sources.
Am I getting confused?😕
First it was LOA, a diffusive light source, then there was a lot of debate on the need for a point light source . Now, within the last 24 hours we have a revival of parabolic reflectors which IMHO takes us right back to diffusive light sources.
Am I getting confused?😕
xblocker... I would agree that a solid understaning of optics would be quite helpful but I am a relatively intelligent person and I am not just going about this blindly. I may make some stupid mistakes I will figure out but I do have some logic to my decisions...Perhaps I can explain my steps and you can help...and dont worry I'm not trying to lash out at you..I really dont mind anyones advice.
My current setup (as many have seen) is layed out on a large piece of plywood. I have the original distances marked off to coincide with my original overhead projector (OK so they are roughly marked off). I have the distance from the fresnel to LCD the same and the distance from the LCD to my lens the same...The only difference is the type and location of my light source and reflector...If you read my previous posts I am trying to take this one step at a time.
So...I figure (and I plan to verify tonight) that the original OHP with its light and reflector focus most of the light to the fresnels with little scatter outside the desired path. Now I cant just put my new bulb in my projector (although I orignally hoped I could..what a fool I was) because it is about 50 times bigger. So I have to obtain a new reflector to focus my light into the fresnel so it can go along its way...and I know it needs to be the proper distance from the fresnel as well (at least I think it does).
This is why I decided to try and build a reflector for my new light... I obtained a highly polished (very close to cylindrical) bowl from WalMart that is near the size of my screen... My understanding of spherical reflectors is that if I place my light in the middle at 1/2 the radius of the sphere it should reflect the light out in parallel...
http://ourworld.compuserve.com/homepages/awi_industries/Optic_reflectors.htm
So I tried this...knowing it is not perfectly parallel but figured I could get it at least close...the problem is the light source, although not like a flourescent light, is spread out over about an inch or so...and it is difficult to get exact...I am able to get a pretty focuses projection of the light but when this happens I get a Very bright image of the filament in the center....
Now I know if I was more exact with everything (down to the millimieter) I would get a better picture, but I am focusing on getting anything close to a doable picture and then I can fine tune from there.
I would really appreciate any suggestions people have but please dont think I am just putting everying in a line and just expecting it to work.
Later...
Dave
My current setup (as many have seen) is layed out on a large piece of plywood. I have the original distances marked off to coincide with my original overhead projector (OK so they are roughly marked off). I have the distance from the fresnel to LCD the same and the distance from the LCD to my lens the same...The only difference is the type and location of my light source and reflector...If you read my previous posts I am trying to take this one step at a time.
So...I figure (and I plan to verify tonight) that the original OHP with its light and reflector focus most of the light to the fresnels with little scatter outside the desired path. Now I cant just put my new bulb in my projector (although I orignally hoped I could..what a fool I was) because it is about 50 times bigger. So I have to obtain a new reflector to focus my light into the fresnel so it can go along its way...and I know it needs to be the proper distance from the fresnel as well (at least I think it does).
This is why I decided to try and build a reflector for my new light... I obtained a highly polished (very close to cylindrical) bowl from WalMart that is near the size of my screen... My understanding of spherical reflectors is that if I place my light in the middle at 1/2 the radius of the sphere it should reflect the light out in parallel...
http://ourworld.compuserve.com/homepages/awi_industries/Optic_reflectors.htm
So I tried this...knowing it is not perfectly parallel but figured I could get it at least close...the problem is the light source, although not like a flourescent light, is spread out over about an inch or so...and it is difficult to get exact...I am able to get a pretty focuses projection of the light but when this happens I get a Very bright image of the filament in the center....
Now I know if I was more exact with everything (down to the millimieter) I would get a better picture, but I am focusing on getting anything close to a doable picture and then I can fine tune from there.
I would really appreciate any suggestions people have but please dont think I am just putting everying in a line and just expecting it to work.
Later...
Dave
Superdave, i understand you wanna set the lightbulb to the point r/2 to get parallel rays towards the fresnel. But:
1. This only works with a pointlight source, otherwise you won't get parallel lightrays.
2. If there indeed were parallel rays which hit the fresnel, then the fresnel should have approx. the same focus lenght as the projection lens to get an image from the light source into the aperture pupil of the projection lens.(OHP mostly have 310mm).
3. 'Normal' OHP-fresnels must have a focal lenght smaller than the distance bulb -- fresnel. Only then the beam is convergent.
4. OHPs have a slighty different design what the reflector concerns. their reflectors project an image of the point light source directly beside the real lightsource. This often has to be adjusted, if the lamp has to be changed.
I would draw a grid onto a plasticfilm or glass and attach it instead of expensive LCD during experimenting. So you can better control geometry and illumination.
Look at this page, which explains the lightpath of a slide projector.The pic shows a double condencer with parallel rays. No parallel rays in OHPS! Could be more detailed i think. important:
The difference between imagepath and illuminationpath !
http://w3.ualg.pt/~jarod/geral/bibliote/phywe/2_1_02.pdf
May be this helps.
cheers
xblocker
1. This only works with a pointlight source, otherwise you won't get parallel lightrays.
2. If there indeed were parallel rays which hit the fresnel, then the fresnel should have approx. the same focus lenght as the projection lens to get an image from the light source into the aperture pupil of the projection lens.(OHP mostly have 310mm).
3. 'Normal' OHP-fresnels must have a focal lenght smaller than the distance bulb -- fresnel. Only then the beam is convergent.
4. OHPs have a slighty different design what the reflector concerns. their reflectors project an image of the point light source directly beside the real lightsource. This often has to be adjusted, if the lamp has to be changed.
I would draw a grid onto a plasticfilm or glass and attach it instead of expensive LCD during experimenting. So you can better control geometry and illumination.
Look at this page, which explains the lightpath of a slide projector.The pic shows a double condencer with parallel rays. No parallel rays in OHPS! Could be more detailed i think. important:
The difference between imagepath and illuminationpath !
http://w3.ualg.pt/~jarod/geral/bibliote/phywe/2_1_02.pdf
May be this helps.
cheers
xblocker
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