Will it hurt the lamp to mount it horizontally accross a board thats perpendicular to the ground (so instead of the lamp FC2 bases facing up, they'd be facing left)? Can I do this or should I not?
?????? Im kinda lost on what your trying to do buddy but aslong as the bulb is horizontal it should be ok. they are rated to work horizontal upto 45 deg vertical.
Trev🙂
Trev🙂
my guess is that he is asking if it can be mounted horizontally instead of vertically. It should be horizontal anyway, just like Trev said.
ok its a cheesy pic I know...but...this is how the setup normally looks (obviously I don't have a reflector or condenser in the pic, but you know what I mean)...now imagine this is a 3d render and you can rotate the pic so the bottoms of the FC2 holders are now facing you (and the lamp facing out away from you)...essentially the lamp would now be on its side. Can you mount the lamp in this way and have it reflect off a cold mirror at a 45° angle? Or should you leave the lamp mounted to the base of the projector box and just move the reflector and condesner accordingly in order for it to reflect off of a 45° mirror?
Attachments
KK, yeah it dont matter which way you have the sockets, all that matters is the bulb running horizontal longways.
Trev🙂
Trev🙂
An externally hosted image should be here but it was not working when we last tested it.
ok I found this pic where it shows exactly what I mean...although the guy who was has it pictured this way does NOT have it this way in his projector...he only has it this way in the pic to show his awesome reflector (which by the way I would LOVE to have so if anyone knows where to get something like that or how to make one, that would be sweet!). So I just wanna know if in my projector, I can mount my lamp setup the way this guy has his pictured.
ok thanks ace! lol...now I know you've seen this guys reflector before...can you help me find something similar or show me how I can make one 😀
lol, np, ill be honest with you, that reflector sure is nice and looks dandy and all but its a bulb killer, it will overheat the bulb. try to get reflectors that have a Dichoric surface or expect your bulb life to be half or even less. Soup laddels are the biggest killer of all time. For a 250w i recomend a Dichoric Spherical or if you can find one that will work, a Dichoric Parabolic or Eliptical. The parabolic doesnt have the be Dichoric as the light isnt going back to the bulb but its advisable, the same goes for the Eliptical.
Trev🙂
Trev🙂
frozenbum...a little time on a metal lathe is all thats required to knock one up mate...but as Trev points out...they are a bulb killer lol
Ace
Help me out buddy. You gotta tell me where to find a dichroic reflector for the 250W hqi bulbs. Right now I am using a glass spherical from anchor optics. 55mm dia. 35mm fl. Is that the focus point (center of sphere) or the focus plane? when I draw it up in autocad, it doesn't look right until I make a 70mm radius arc for the reflecting sphere, which would put that quoted fl at the focus plane (where everything is reflected back on a parrallel light path). Soon as I upload the pics from my camera, I'll post the ones from my test bench.
Steamer
Help me out buddy. You gotta tell me where to find a dichroic reflector for the 250W hqi bulbs. Right now I am using a glass spherical from anchor optics. 55mm dia. 35mm fl. Is that the focus point (center of sphere) or the focus plane? when I draw it up in autocad, it doesn't look right until I make a 70mm radius arc for the reflecting sphere, which would put that quoted fl at the focus plane (where everything is reflected back on a parrallel light path). Soon as I upload the pics from my camera, I'll post the ones from my test bench.
Steamer
Ace must be on holiday?
So I'll just jump in here:
Steamer: You are correct, sir! The optics companies quote the "focal length" of a spherical reflector as half the center of curvature distance. "Focal Length" is really a misnomer for a spherical reflector, since that is the point where some of the light from a parallel beam would focus. But as soon as you get away from the center of the mirror, the "focus" goes way off. See the image below. It shows what happens to parallel rays when they hit a spherical reflector.
For the way spherical light reflectors get used, it makes a lot more sense to quote the center of curvature. That is where you put the bulb arc.
A good source of cheap dichroic spherical mirrors would be great!
The only one I have found that is big enough, is the 65 mm diameter, 21.5 mm fl spherical cold mirror from Rolyn Optics for $517.40 US!!!!! I think I would rather use a metal reflector and replace my $38 bulb every 5000 hours instead of the rated 10000 hours! It would take 54 years for the cold mirror to pay for the extra bulbs.
So I'll just jump in here:
Steamer: You are correct, sir! The optics companies quote the "focal length" of a spherical reflector as half the center of curvature distance. "Focal Length" is really a misnomer for a spherical reflector, since that is the point where some of the light from a parallel beam would focus. But as soon as you get away from the center of the mirror, the "focus" goes way off. See the image below. It shows what happens to parallel rays when they hit a spherical reflector.
For the way spherical light reflectors get used, it makes a lot more sense to quote the center of curvature. That is where you put the bulb arc.
A good source of cheap dichroic spherical mirrors would be great!
The only one I have found that is big enough, is the 65 mm diameter, 21.5 mm fl spherical cold mirror from Rolyn Optics for $517.40 US!!!!! I think I would rather use a metal reflector and replace my $38 bulb every 5000 hours instead of the rated 10000 hours! It would take 54 years for the cold mirror to pay for the extra bulbs.
Attachments
pretty reflector
I looked at that guy's reflector again, and it does not look like a spherical reflector to me. Notice that the center of the bulb tube passes through the reflector pretty far down into it. If it was spherical, then any reflector surface "above" the bulb arc would do no good and only heat the bulb.
I think it must be a parabolic reflector, which would agree with the bulb arc position.
But there is one unsurmountable problem with using a parabolic reflector like this: The reflected rays leave the light engine in a parallel beam, so no lower fresnel is needed to bend the light at the LCD to be parallel. The direct rays leave the light engine in a diverging cone, so they need a lower fresnel to bend them to be parallel. No fresnel and you lose the direct light. Add a fresnel and you lose the reflected light. Either way, half the light will never make it to the projection lens. In fact, the image would probably look better if you left out the reflector! The only way to fix this is to add a tiny spherical reflector to the front side of the bulb. So what was the direct light, heads back through the bulb arc into the parabolic reflector. Oops! Overheated bulb again!
But it is darned pretty! Which should teach us all an important lesson: Nice chrome doesn't make the car go any faster! 😀
I looked at that guy's reflector again, and it does not look like a spherical reflector to me. Notice that the center of the bulb tube passes through the reflector pretty far down into it. If it was spherical, then any reflector surface "above" the bulb arc would do no good and only heat the bulb.
I think it must be a parabolic reflector, which would agree with the bulb arc position.
But there is one unsurmountable problem with using a parabolic reflector like this: The reflected rays leave the light engine in a parallel beam, so no lower fresnel is needed to bend the light at the LCD to be parallel. The direct rays leave the light engine in a diverging cone, so they need a lower fresnel to bend them to be parallel. No fresnel and you lose the direct light. Add a fresnel and you lose the reflected light. Either way, half the light will never make it to the projection lens. In fact, the image would probably look better if you left out the reflector! The only way to fix this is to add a tiny spherical reflector to the front side of the bulb. So what was the direct light, heads back through the bulb arc into the parabolic reflector. Oops! Overheated bulb again!
But it is darned pretty! Which should teach us all an important lesson: Nice chrome doesn't make the car go any faster! 😀
Spherical reflector
Okay,
So where should I place my bulb in relation to my reflector? at the focal plane, the focal point, or somewhere in between? I also have an 88mm dia *precondensor* with a 110 mm fl.
Man, this is becoming more complicated than I would like. But, whaddyagonnado?
Steamer
Okay,
So where should I place my bulb in relation to my reflector? at the focal plane, the focal point, or somewhere in between? I also have an 88mm dia *precondensor* with a 110 mm fl.
Man, this is becoming more complicated than I would like. But, whaddyagonnado?
Steamer
>where does it all go?
Here is a drawing for you. It shows how to use a big reflector or a small reflector. Either way, you put the center of the bulb arc at the center of curvature of the sphere. That is the point that is equidistant from all points on the reflector surface. If you have a quoted "focal length" for your reflector, then it is two times that distance.
The other thing to get right, is that the spherical reflector has to be wide enough so the full width of the condensor lens is covered with reflected light. Otherwise you would see dimmer edges in your projected image. Of course, this is angle is affected by how close you put your condensor to the bulb. And that is affected by how the light spreads out to the lower fresnel.
So you really need to work backwards:
1) Find the right distance between the condensor lens and the lower fresnel, so the width of the condensor lens intersects the cone of light expected by the fresnel. (ie. A 220 mm fl fresnel expects light to come from a focal point 220 mm from the lens. Make a full scale drawing to see where your condensor lens has to go so the fresnel "sees" the light as if it was 220 mm away.)
2) Make a ray tracing drawing of the light being bent by the condensor lens to get to the fresnel edges. Then measure the distance for the bulb arc to the condensor lens, right off the drawing.
3) Put the reflector behind the bulb so the center of the bulb arc is at the center of curvature.
If you start with all the parts adjustable, then you can do all of this using the light from the bulb! Instead of ray tracing, you do this:
1) Do step 1 above to figure out the condensor lens-to-fresnel distance. Fix the positions of both at that distance.
2) Put a piece of white paper against the LCD.
3) Move the bulb position until the condensor and lower fresnel are filling the LCD with a nice uniform light. If the rectangle of light is the same size as the lower fresnel, then you have the distance from the fresnel to the virtual bulb arc correct.
4) Put the reflector behind the bulb so the center of the bulb arc is at the center of curvature. The light falling on the piece of paper should get brighter.
Here is a drawing for you. It shows how to use a big reflector or a small reflector. Either way, you put the center of the bulb arc at the center of curvature of the sphere. That is the point that is equidistant from all points on the reflector surface. If you have a quoted "focal length" for your reflector, then it is two times that distance.
The other thing to get right, is that the spherical reflector has to be wide enough so the full width of the condensor lens is covered with reflected light. Otherwise you would see dimmer edges in your projected image. Of course, this is angle is affected by how close you put your condensor to the bulb. And that is affected by how the light spreads out to the lower fresnel.
So you really need to work backwards:
1) Find the right distance between the condensor lens and the lower fresnel, so the width of the condensor lens intersects the cone of light expected by the fresnel. (ie. A 220 mm fl fresnel expects light to come from a focal point 220 mm from the lens. Make a full scale drawing to see where your condensor lens has to go so the fresnel "sees" the light as if it was 220 mm away.)
2) Make a ray tracing drawing of the light being bent by the condensor lens to get to the fresnel edges. Then measure the distance for the bulb arc to the condensor lens, right off the drawing.
3) Put the reflector behind the bulb so the center of the bulb arc is at the center of curvature.
If you start with all the parts adjustable, then you can do all of this using the light from the bulb! Instead of ray tracing, you do this:
1) Do step 1 above to figure out the condensor lens-to-fresnel distance. Fix the positions of both at that distance.
2) Put a piece of white paper against the LCD.
3) Move the bulb position until the condensor and lower fresnel are filling the LCD with a nice uniform light. If the rectangle of light is the same size as the lower fresnel, then you have the distance from the fresnel to the virtual bulb arc correct.
4) Put the reflector behind the bulb so the center of the bulb arc is at the center of curvature. The light falling on the piece of paper should get brighter.
Attachments
Sorry guys, im not on holiday just darn busy, ( R&D as usual), in a matter of fact working with reflectors strangly enough lol.
In case you want to know, the reflector is the most important peice in or projectors, the coating of the reflector second, though thats debatable. The more light we can ACURATLEY guide from our source the brighter our image becomes hence a higher eficentcy.
My findings:
You have 2 choices to get a semi decent diy projector that stands upto or surpases pro projectors. Lets not forget this is on a 7inch lcd.
1) A GOLD coated dichoric parabolic reflector, forget the silver dichoric as its ****. You see a masive diffence in image quality between the 2 mainly being acuracy in colours and brightness.
Only a gold dichoric coating will give you an image thats either identical or somwhat very like a pro projector. Colour shift on a gold dichoric reflector is also higher. This means the bulbs colour that would normally be 4200k will be around 5500k!!! after being reflected. My image tells me its more like the light is around 6000k though i dont have the full specific specs on the current reflector i tested and own.
Another good point to bring up is the lamp doesnt have to be as far away from the frensels, this can yeald us a much brighter image. We also dont have an issue with heat, and we dont need a condenser. We also use more of our light and from the such high colour shift we can use standard cheap readily available mh bulbs such as the CDM-T for very desired results.
Dont use shallow designed parabolics, use the deep design, as the shallow waste more light like you wouldnt beleive it.
Pros: Reflect more light
Higher colour shift
Less heat
Higher eficientcy
Very acurate image quality and contrast, higher sharpness
Last for years
Cons: Availability
Price
For best results, better to be custom made
2) The second way to get things super bright and efficent is the spherical way. While this isnt the best way it works, and its somewhat cheaper. However there are a few things to overcome, 1 being heat on our optics and surounding areas while the second being efficientcy.
DONT go using a soup laddel, its like injecting your projector with the aids virus, as eventually it will die from heat along with your bulb. Soup laddels are also not acurate and will purley give you a blured light.
Heat on the optics.
Well i think this is farly self explanitory, having a condenser close to the bulb is surley going to get hot. On a 250w HQI the condenser will reach 300deg c +. Make sure its Borosilicate 270 or Pyrex and add active cooling on the condenser such as a fan. Failing to do so the condenser will simply explode no matter what coating is on the reflector, dichoric or not. Temperd glass will also explode and weakens with age in our systems.
What condenser to use.
In my findings the best types of condensers to use are either + focal pcx or aspherical. Hands down aspherical wins the race but availablity is again short, and can be costly. DONT go using a DCX as they are simply just full of Coma distortion and reflection. They waste light.
Depending on your setup your focal will vary. In a small lcd system like mine (7inch lcd is very big to me btw), try to find a lens with a focal of around 50-60mm with a diameter of about 60-70mm. The bigger the diameter is on the lens the less brightness you will acheive. ( on frensels being 210mm focal bottom and 310mm top).
Just lately ive realised a very big mistake that we are all doing, its also why we are using 250 and 400w lamps rather then just a needed 150w. So........ what are we doing wrong? its fairly simple. We are not condensing our arc, we are condensing radiated light from it. So what you may say, i can tell you right now its 4x brighter and the colour of the light is somewhat very acurate rather then the dirty look. Its also what the pro projectors did in the older models and the difference is simply amazing.
However, we have a problem, the bulbs we use are too big, also our arcs are miles too big (meaning we dont need an arc that big as all we need is 2mm of arc to get the same result) and therfore we cant just quite get the condenser close enough to the arc for where it needs to be. Ive got my eye on a new bulb, it will fit the job perfect.
The way we do things now is also giving us the hotspot. The condensing of the arc as what im doing gives very near perfect image luminisy. The sides will always be slightly dimmer. Why? well unless you plan to use aspheric frensels then your going to get distortions on the edges of your frensels, its not actually from the condenser, its a problem with the frensels we use. The frensels we use are the same as if we wer using 2x pcx lenses, only an aspheric frensel set will fix this problem. However with the condensing of the arc this problem is hardly noticable compared to the typical way we do things now. Infact you have to look for it.
An advantage to the condensing of the actual arc is the very big difference a shperical reflector makes. You soon see the brightness gain and wheather the lamp is at the reflectors focal or not. Failing to have the lamp at the reflectors focal soon gives you distorted light, while when it is at its focal the image is as sharp as can be.
Ok, back to spherical reflectors. The focal on a shperical reflector is the center of the sphere. All light from the source will go back through this focal point hence back through the source. There is a big difference in brightness, but nothing compared to when we condense the arc as mentioned above. We can also run a spherical reflector as a parabolic, simply place the lamp at half focal.
What coating to choose?
Thats simple, dichoric. Why? colour shift, less heat on the condenser and lamps arc tube, eficientcy. What happends if we use a normal aluminiumised reflector and have the light going back to its source? it overheats. What happends if we overheat our bulb? it can explode, we burn the chemicals inside the arc tube thats gives us less of the bulbs life (beleive me it fryies it off), and the condenser is going to run hotter. What causes this damage? IR light. Simple solution, use dichoric, it will only reflect 10% IR if that, while reflecting all other spectrums.
So when using the dichoric reflector, the bulb is as hot as if it was free standing, and the condenser is only going to get as hot as the specified heat from the lamp, ( remember roughly 10% hotter compared to 30-50%). You can use aluminiumised spherical reflectors so long as they are reasonably small. Just remember the bigger the reflector, the more un filtered light (if non dichoric)you direct back to the bulb, which in turn the more heat and damage you are doing. And thats the biggest reason why a soup laddle will fry your bulb and condenser, (your trapping you bulb and condenser in its own oven).
Size isnt realy an issue, however there is a stage when things are too small and too big. The correct size is to have a spherical reflector 2x the size of the arc, this maximises eficientcy.
There are also 2 types of shapes in spherical reflectors, there is the 1/2 sphere or the 1/4 sphere. For best results go the 1/4 sphere, the 1/2 sphere has alot more spherical abberations. One thing to keep in mind though is that the 1/4 sphere run better at 3x the bulbs arc size.
Pros: Cost
Availability
Size
Cons: Eficientcy
More fooling around
Condenser
Condenser heat issues
Slightly lower bulb life (if using dichoric)
Very short bulb life (if aluminiumised)
To sum things up, in a way these 2 sysems work the same, both parabolic and spherical that is (only when condensing the arc). There realy isnt that much of a difference but the parabolic is going to be the easiest way to do things and by far its more eficient. The problem is just the cost of the parabolic. Its best realy to use the spherical as an alternative if one cant aford the other.
The other thing is the parabolic wont have any distortions like the spherical. With spherical reflectors there is always to some degree of spherical abberations and abberations from our condenser. High quality parts can be had for a reasonable price these days and distortion isnt becoming somewhat an issue.
My advice, get some good gear no matter what system you choose, in the long run its well worth it, you will have your expectations matched if not outdone and the projector will last for years. The extra you pay in parts will soon cover the extra cost of bulbs/LCD's you would soon be buying.
What system am i choosing? undecided, im kinda broke lol. But at the end of the day i will find a system that meets all of you guys needs on the cheap, giving you all outstanding results. That is my mission, and its very close to beeing completed.
Anyway i hope this post helped you guys out abit, sorry for it being so long.
Trev🙂
In case you want to know, the reflector is the most important peice in or projectors, the coating of the reflector second, though thats debatable. The more light we can ACURATLEY guide from our source the brighter our image becomes hence a higher eficentcy.
My findings:
You have 2 choices to get a semi decent diy projector that stands upto or surpases pro projectors. Lets not forget this is on a 7inch lcd.
1) A GOLD coated dichoric parabolic reflector, forget the silver dichoric as its ****. You see a masive diffence in image quality between the 2 mainly being acuracy in colours and brightness.
Only a gold dichoric coating will give you an image thats either identical or somwhat very like a pro projector. Colour shift on a gold dichoric reflector is also higher. This means the bulbs colour that would normally be 4200k will be around 5500k!!! after being reflected. My image tells me its more like the light is around 6000k though i dont have the full specific specs on the current reflector i tested and own.
Another good point to bring up is the lamp doesnt have to be as far away from the frensels, this can yeald us a much brighter image. We also dont have an issue with heat, and we dont need a condenser. We also use more of our light and from the such high colour shift we can use standard cheap readily available mh bulbs such as the CDM-T for very desired results.
Dont use shallow designed parabolics, use the deep design, as the shallow waste more light like you wouldnt beleive it.
Pros: Reflect more light
Higher colour shift
Less heat
Higher eficientcy
Very acurate image quality and contrast, higher sharpness
Last for years
Cons: Availability
Price
For best results, better to be custom made
2) The second way to get things super bright and efficent is the spherical way. While this isnt the best way it works, and its somewhat cheaper. However there are a few things to overcome, 1 being heat on our optics and surounding areas while the second being efficientcy.
DONT go using a soup laddel, its like injecting your projector with the aids virus, as eventually it will die from heat along with your bulb. Soup laddels are also not acurate and will purley give you a blured light.
Heat on the optics.
Well i think this is farly self explanitory, having a condenser close to the bulb is surley going to get hot. On a 250w HQI the condenser will reach 300deg c +. Make sure its Borosilicate 270 or Pyrex and add active cooling on the condenser such as a fan. Failing to do so the condenser will simply explode no matter what coating is on the reflector, dichoric or not. Temperd glass will also explode and weakens with age in our systems.
What condenser to use.
In my findings the best types of condensers to use are either + focal pcx or aspherical. Hands down aspherical wins the race but availablity is again short, and can be costly. DONT go using a DCX as they are simply just full of Coma distortion and reflection. They waste light.
Depending on your setup your focal will vary. In a small lcd system like mine (7inch lcd is very big to me btw), try to find a lens with a focal of around 50-60mm with a diameter of about 60-70mm. The bigger the diameter is on the lens the less brightness you will acheive. ( on frensels being 210mm focal bottom and 310mm top).
Just lately ive realised a very big mistake that we are all doing, its also why we are using 250 and 400w lamps rather then just a needed 150w. So........ what are we doing wrong? its fairly simple. We are not condensing our arc, we are condensing radiated light from it. So what you may say, i can tell you right now its 4x brighter and the colour of the light is somewhat very acurate rather then the dirty look. Its also what the pro projectors did in the older models and the difference is simply amazing.
However, we have a problem, the bulbs we use are too big, also our arcs are miles too big (meaning we dont need an arc that big as all we need is 2mm of arc to get the same result) and therfore we cant just quite get the condenser close enough to the arc for where it needs to be. Ive got my eye on a new bulb, it will fit the job perfect.
The way we do things now is also giving us the hotspot. The condensing of the arc as what im doing gives very near perfect image luminisy. The sides will always be slightly dimmer. Why? well unless you plan to use aspheric frensels then your going to get distortions on the edges of your frensels, its not actually from the condenser, its a problem with the frensels we use. The frensels we use are the same as if we wer using 2x pcx lenses, only an aspheric frensel set will fix this problem. However with the condensing of the arc this problem is hardly noticable compared to the typical way we do things now. Infact you have to look for it.
An advantage to the condensing of the actual arc is the very big difference a shperical reflector makes. You soon see the brightness gain and wheather the lamp is at the reflectors focal or not. Failing to have the lamp at the reflectors focal soon gives you distorted light, while when it is at its focal the image is as sharp as can be.
Ok, back to spherical reflectors. The focal on a shperical reflector is the center of the sphere. All light from the source will go back through this focal point hence back through the source. There is a big difference in brightness, but nothing compared to when we condense the arc as mentioned above. We can also run a spherical reflector as a parabolic, simply place the lamp at half focal.
What coating to choose?
Thats simple, dichoric. Why? colour shift, less heat on the condenser and lamps arc tube, eficientcy. What happends if we use a normal aluminiumised reflector and have the light going back to its source? it overheats. What happends if we overheat our bulb? it can explode, we burn the chemicals inside the arc tube thats gives us less of the bulbs life (beleive me it fryies it off), and the condenser is going to run hotter. What causes this damage? IR light. Simple solution, use dichoric, it will only reflect 10% IR if that, while reflecting all other spectrums.
So when using the dichoric reflector, the bulb is as hot as if it was free standing, and the condenser is only going to get as hot as the specified heat from the lamp, ( remember roughly 10% hotter compared to 30-50%). You can use aluminiumised spherical reflectors so long as they are reasonably small. Just remember the bigger the reflector, the more un filtered light (if non dichoric)you direct back to the bulb, which in turn the more heat and damage you are doing. And thats the biggest reason why a soup laddle will fry your bulb and condenser, (your trapping you bulb and condenser in its own oven).
Size isnt realy an issue, however there is a stage when things are too small and too big. The correct size is to have a spherical reflector 2x the size of the arc, this maximises eficientcy.
There are also 2 types of shapes in spherical reflectors, there is the 1/2 sphere or the 1/4 sphere. For best results go the 1/4 sphere, the 1/2 sphere has alot more spherical abberations. One thing to keep in mind though is that the 1/4 sphere run better at 3x the bulbs arc size.
Pros: Cost
Availability
Size
Cons: Eficientcy
More fooling around
Condenser
Condenser heat issues
Slightly lower bulb life (if using dichoric)
Very short bulb life (if aluminiumised)
To sum things up, in a way these 2 sysems work the same, both parabolic and spherical that is (only when condensing the arc). There realy isnt that much of a difference but the parabolic is going to be the easiest way to do things and by far its more eficient. The problem is just the cost of the parabolic. Its best realy to use the spherical as an alternative if one cant aford the other.
The other thing is the parabolic wont have any distortions like the spherical. With spherical reflectors there is always to some degree of spherical abberations and abberations from our condenser. High quality parts can be had for a reasonable price these days and distortion isnt becoming somewhat an issue.
My advice, get some good gear no matter what system you choose, in the long run its well worth it, you will have your expectations matched if not outdone and the projector will last for years. The extra you pay in parts will soon cover the extra cost of bulbs/LCD's you would soon be buying.
What system am i choosing? undecided, im kinda broke lol. But at the end of the day i will find a system that meets all of you guys needs on the cheap, giving you all outstanding results. That is my mission, and its very close to beeing completed.
Anyway i hope this post helped you guys out abit, sorry for it being so long.
Trev🙂
Guy, i see there is abit of confusion going on from your findings and ill try to help you out here.
In a total paralelle type projector system the condenser must be atleast 10% bigger then the projectors objective lens, the same goes for the reflector asuming its parabolic.
In a system like ours thats non paralelle the size of the condenser and reflector is somewhat different. The spherical reflector must be roughly 2x the size of the arc. The condenser you can do 2 ways though realy there is only 1. Basically it has to be bigger then the angle of the focal lines from your frensels focal, the closer the condenser is to the arc the smaller it can be.
Frensels in both systems shouls be Atleast 10% bigger then the image plane.
I hope that helps you out abit🙂
Trev🙂
In a total paralelle type projector system the condenser must be atleast 10% bigger then the projectors objective lens, the same goes for the reflector asuming its parabolic.
In a system like ours thats non paralelle the size of the condenser and reflector is somewhat different. The spherical reflector must be roughly 2x the size of the arc. The condenser you can do 2 ways though realy there is only 1. Basically it has to be bigger then the angle of the focal lines from your frensels focal, the closer the condenser is to the arc the smaller it can be.
Frensels in both systems shouls be Atleast 10% bigger then the image plane.
I hope that helps you out abit🙂
Trev🙂
I'm more confused now than ever before.
It all made sense, Trev, but my specific issue is still not resolved. I thought I should set my reflector at half its focal (which makes the lightpath parrallel), but I'm not sure where the condensor would come in.
If I remember correctly, an arc from a 250w HQI is about 20mm. My reflector is 55mm. So I'm safe there. I know, pretty much, where to put it.
My condensor is 88mm. It has a FL of 110mm. My rear fresnal's FL is 200mm. Do I even need a condensor? I'm pretty sure I do. I have no idea where it belongs. If the light coming at it is parrallel, it doesn't really matter how far from the source it is, right? It just matters how far from the rear fresnal.
Then again, that is not entirely true, since the light from the front of the bulb is coming from different angles, not parrallel.
Help me out, light ray gurus!
Steamer
It all made sense, Trev, but my specific issue is still not resolved. I thought I should set my reflector at half its focal (which makes the lightpath parrallel), but I'm not sure where the condensor would come in.
If I remember correctly, an arc from a 250w HQI is about 20mm. My reflector is 55mm. So I'm safe there. I know, pretty much, where to put it.
My condensor is 88mm. It has a FL of 110mm. My rear fresnal's FL is 200mm. Do I even need a condensor? I'm pretty sure I do. I have no idea where it belongs. If the light coming at it is parrallel, it doesn't really matter how far from the source it is, right? It just matters how far from the rear fresnal.
Then again, that is not entirely true, since the light from the front of the bulb is coming from different angles, not parrallel.
Help me out, light ray gurus!
Steamer
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