Hi!
I'm building my first pj with a 5" lcd, but my projected image appears to be dim for a 400W. I apologize for the drawings, my girlfriend stole my camera and I just have 1 pic of the proyected image, but I made an Autocad drawing.
This is what I have so far:
5"lcd (low rez,just for movies)
Sylvania MH 400, compact bulb, 40mm arc lenght (Heat is not a problem)
Ballast (heavy, not too noisy)
Half sphere reflector (soup ladle)
Projection lens (50mm long, 40mm diameter, 170mm FL)
2 80mm Fans at full speed
Tempered glass ( Will get an IR filter soon)
Blackout Cloth
And 3 Fresnel lenses, two of them have the same FL (the acrylic ones):
2 acrylic fresnels (great quality!)
The third fresnel is just a magnifyng sheet of thin plastic
Focal lenghts? Thats the problem!!
I HAVE MADE THE SETUP #1, with the focal lenghts calculated using the bulb inside my bedroom, the setup #2 takes place if I use the sun:
Setup#1:
Acrylic fresnel x2 : 400mm FL
Plastic fresnel x1: 350mm FL
Setup#2:
Acrylic fresnel x2 : 330mm FL
Plastic fresnel x1: 290mm FL
Recently I removed the 400W with spherical reflector and added a 250w halogen lamp with a dicroic reflector (was placed at the same distance) . Unfortunately I discovered the new image was like 30% brighter with the halogen!!!
Obviously it had a yellowish color, but man! something must be wrong if a 250w Halogen beats a 400w MH. Of course we need to consider the reflectors (spherical vs parabolic), and maybe the arc lenght, but the rest of the setup was the same, even the soup ladle Im using is shiny, like a brand new rim.
This is the top view of what I have so far (setup #1):
Im using two lenses against each other in order to cut by half the FL ( I dont have hotspots).
And this is what it'd look like with the 2nd setup:
Please share your wisdom and Feel free to use my drawings in order to correct my mistakes
What Am I doing wrong? Should I go with setup #2? What is the best way to find the fresnel's FL? How can I improve the brightness?
Any Advice will be apreciated
Thanks 🙂 !!
I'm building my first pj with a 5" lcd, but my projected image appears to be dim for a 400W. I apologize for the drawings, my girlfriend stole my camera and I just have 1 pic of the proyected image, but I made an Autocad drawing.
This is what I have so far:
5"lcd (low rez,just for movies)
Sylvania MH 400, compact bulb, 40mm arc lenght (Heat is not a problem)
Ballast (heavy, not too noisy)
Half sphere reflector (soup ladle)
Projection lens (50mm long, 40mm diameter, 170mm FL)
2 80mm Fans at full speed
Tempered glass ( Will get an IR filter soon)
Blackout Cloth
And 3 Fresnel lenses, two of them have the same FL (the acrylic ones):
2 acrylic fresnels (great quality!)
The third fresnel is just a magnifyng sheet of thin plastic
Focal lenghts? Thats the problem!!
I HAVE MADE THE SETUP #1, with the focal lenghts calculated using the bulb inside my bedroom, the setup #2 takes place if I use the sun:
An externally hosted image should be here but it was not working when we last tested it.
Setup#1:
Acrylic fresnel x2 : 400mm FL
Plastic fresnel x1: 350mm FL
Setup#2:
Acrylic fresnel x2 : 330mm FL
Plastic fresnel x1: 290mm FL
Recently I removed the 400W with spherical reflector and added a 250w halogen lamp with a dicroic reflector (was placed at the same distance) . Unfortunately I discovered the new image was like 30% brighter with the halogen!!!
An externally hosted image should be here but it was not working when we last tested it.
Obviously it had a yellowish color, but man! something must be wrong if a 250w Halogen beats a 400w MH. Of course we need to consider the reflectors (spherical vs parabolic), and maybe the arc lenght, but the rest of the setup was the same, even the soup ladle Im using is shiny, like a brand new rim.
This is the top view of what I have so far (setup #1):
An externally hosted image should be here but it was not working when we last tested it.
Im using two lenses against each other in order to cut by half the FL ( I dont have hotspots).
And this is what it'd look like with the 2nd setup:
An externally hosted image should be here but it was not working when we last tested it.
Please share your wisdom and Feel free to use my drawings in order to correct my mistakes
What Am I doing wrong? Should I go with setup #2? What is the best way to find the fresnel's FL? How can I improve the brightness?
Any Advice will be apreciated
Thanks 🙂 !!
in your setup 1 your bulb is not at an infinite distance like the sun in your setting 2. Then for the setting 1 you have to use the following formula to get the focal of your fresnel:
1/focal= (1/distance bulb-fresnel) + (1/distance fresnel-image of the bulb)
this way you should find the same focal between setting1 and setting2
I fthink you'll find the 330 and 290 value
nice design.
1/focal= (1/distance bulb-fresnel) + (1/distance fresnel-image of the bulb)
this way you should find the same focal between setting1 and setting2
I fthink you'll find the 330 and 290 value
nice design.
Allright!, I checked the FL of the same acrylic fresnel using a sheet of paper at 3 distances from my room's bulb, unfortunately, the tests dropped different results. All units are in cm in order to switch to mm easily. (grooves facing up).
Test 1:
1/focal= (1/distance bulb-fresnel) + (1/distance fresnel-image of the bulb)
1/focal= (1/163) + (1/400)
1/focal= 103/252
focal= 24.46cm= 244 mm FL
Test 2:
1/focal= (1/242) + (1/39)
1/focal= 281/9438
focal= 33.58cm = 335 mm FL
Test 3:
1/focal= (1/138) + (1/50)
1/focal= 47/1725
focal= 36.70cm= 367 mm FL
Which one of the 3 is correct? Or should I stay with the focal lenght calculated using the sun.
Something else: Isnt there some kind of standard whenever youre trying to find a fresnel's Focal lenght?
For example, Ive searched all over the forums and I see diyers using 220mm, 330mm and 450mm Fl fresnels. Nothing else.
Does that mean you cant find a fresnel with a focal lenght of 277mm? Coz if thats true, It looks like I only need to find if the focal lenght of my fresnels is eiter 220, 330 or 450 mm right?
Man, Im getting confused. Well , Im willing to do everything in order to get a brighter image.
Any comments? 🙂
An externally hosted image should be here but it was not working when we last tested it.
Test 1:
1/focal= (1/distance bulb-fresnel) + (1/distance fresnel-image of the bulb)
1/focal= (1/163) + (1/400)
1/focal= 103/252
focal= 24.46cm= 244 mm FL
Test 2:
1/focal= (1/242) + (1/39)
1/focal= 281/9438
focal= 33.58cm = 335 mm FL
Test 3:
1/focal= (1/138) + (1/50)
1/focal= 47/1725
focal= 36.70cm= 367 mm FL
Which one of the 3 is correct? Or should I stay with the focal lenght calculated using the sun.
Something else: Isnt there some kind of standard whenever youre trying to find a fresnel's Focal lenght?
For example, Ive searched all over the forums and I see diyers using 220mm, 330mm and 450mm Fl fresnels. Nothing else.
Does that mean you cant find a fresnel with a focal lenght of 277mm? Coz if thats true, It looks like I only need to find if the focal lenght of my fresnels is eiter 220, 330 or 450 mm right?
Man, Im getting confused. Well , Im willing to do everything in order to get a brighter image.
Any comments? 🙂
Ooops! the drawing is in mm, not cm. Please dont consider the last digit of the drawings ok?
Everything else is allright
Everything else is allright
I assume that the setup2 give you better results.
In setup one depnding on the bulb-lens distance (BLD) you may have some distortion.
Usually the BLD with the more accurate result is around 2 time the estimated focal.
In addition it would be better to take a flat objet instead of the buls as object since it's not flat and may induce wrong estimation of the distance.
Do measurements with BLD around 2 time the estimate focal and do this measurements 5 times get the mean and SD.
In your 3 measure we don't know if this is an error due to the various distance or to the variuos measurements.
In setup one depnding on the bulb-lens distance (BLD) you may have some distortion.
Usually the BLD with the more accurate result is around 2 time the estimated focal.
In addition it would be better to take a flat objet instead of the buls as object since it's not flat and may induce wrong estimation of the distance.
Do measurements with BLD around 2 time the estimate focal and do this measurements 5 times get the mean and SD.
In your 3 measure we don't know if this is an error due to the various distance or to the variuos measurements.
Where did you get the fresnels? are they page magnifiers? and yes, generally there really aren't that many different FLs for fresnels.... I can't imagine you got a 400mm though it is possible....220-330 are the limits usually... make sure you build your box so you can adjust the lenses a lot, in my pj, even though I knoew the FL (22/317) I still had to adjust it all manually, and they did not end up at the "calculated" distances for best brightness.... plus, with a small lcd, you just aren't capturing as much light as with a 15" lcd with the same bulb(in fact I think its 1/9th the amount) .... search on "precondenser" .... halving the FL for the rear should help a lot too, but again, don't count on the calculations being perfect....
Thanks for the tip! I got the fresnels from a store that sells/trades office supplies, here are the specs:
Apollo Full-Page Handheld Magnifier, Full Page High Power Magnifier, 8-1/2"x12"x1/8", 2X POWER
Apollo's high power magnifier is great for up-close viewing of fine print in stock listings, newspapers, maps, computer printouts, photographs, drawings and all fine prints. Manufactured with shatterproof, scratch resistant, optical-grade acrylic lenses. 8 1/2" x 11" 2X lens enlarges an entire page all at once. Designed to provide years of reliable, distortion-free performance. Made of rigid acrylic for easy handling.
2X Power Magnification;Clear.
They didnt know the Fl, but the description says : 2X
1) IS IT POSSIBLE TO FIND THE FL IF YOU ONLY KNOW THE MAG. POWER? IF NOT, THEN WHAT DOES 2X MEAN?
Id like to add a precondenser lens, coz it willl increase the brightness a lot. As I said, Heat is not a problem, so I dont need pyrex or something like that. Its just I dont have any idea about which one to buy, of course it must be a PCX , but thats all I know.
This is the list from surplusshed (huge 🙂 ),
2) COULD YOU TELL ME WHICH ONE MIGHT WORK BEST WITH MY SETUP? (LETS SAY I USE SETUP #2).
The diameter of the reflector is 140mm, and as a true sphere, its FL is 70mm. The lamp arc is 40mm. And the distance from the lamp arc to the outer envelope of the bulb is 45mm.
Diameter FL Coated
mm mm
L7374 PCX 82.0 143 N $4.00
L7396 PCX 81.0 222 N $4.00
L5091 PCX 66.0 139 Y $4.00
L8008 PCX 65.3 129 Y $4.00
L8000 PCX 65.2 129 Y $4.00
L8006 PCX 63.6 308 N $4.00
L8005 PCX 63.5 114 N $4.00
L4298 PCX 59.7 62 N $4.00
L6223 PCX 56.0 174 Y $4.00
L4101 PCX 52.6 80 Y $4.00
L4336 PCX 52.5 80 Y $4.00
L6260 PCX 51.5 103 N $4.00
L7387 PCX 50.0 114 N $4.00
L8115 PCX 48.0 82 Y $4.00
L4521 PCX 47.6 154 N $4.00
L4307 PCX 46.0 62 Y $4.00
L5266 PCX 44.0 80 Y $4.00
L5367 PCX 44.0 80 Y $4.00
L8058 PCX 42.5 181 Y $4.00
L7068 PCX 42.4 -108 Y $4.00
L4548 PCX 42.2 79 N $4.00
L8097 PCX 42.0 143 Y $4.00
L7391 PCX 41.0 82 N $4.00
L4074 PCX 38.8 62 Y $4.00
L5015 PCX 38.8 69 Y $4.00
L5705 PCX 38.0 101 Y $4.00
L5193 PCX 37.5 68 Y $4.00
L5340 PCX 37.5 68 Y $4.00
L5722 PCX 37.5 65 Y $4.00
L5853 PCX 37.2 53 Y $4.00
L5004 PCX 36.8 390 Y $4.00
L5114 PCX 36.0 131 N $4.00
L4368 PCX 35.6 286 Y $4.00
L5203 PCX 35.0 41 Y $4.00
L8081 PCX 35.0 103 Y $4.00
L8110 PCX 35.0 57 Y $4.00
L6239 PCX 34.9 40 Y $4.00
L6435 PCX 34.9 211 Y $4.00
L6434 PCX 34.7 103 Y $4.00
L5064 PCX 34.5 66 Y $4.00
L5072 PCX 34.5 87 Y $4.00
L4369 PCX 32.5 308 Y $4.00
L6222 PCX 32.1 143 Y $4.00
L6661 PCX 32.0 286 N $4.00
L4662 PCX 31.0 191 N $4.00
L5948 PCX 31.0 54 Y $4.00
L4522 PCX 30.0 53 Y $4.00
L4534 PCX 30.0 93 N $4.00
L6181 PCX 30.0 81 Y $4.00
L6437 PCX 29.0 100 N $4.00
L6436 PCX 28.9 50 N $4.00
L6200 PCX 28.5 68 Y $4.00
L5956 PCX 28.1 561 Y $4.00
L2179 PCX 28.0 59 Y $4.00
L5086 PCX 27.0 53 Y $4.00
L6416 PCX 27.0 33 Y $4.00
L7383 PCX 27.0 32 N $4.00
L5062 PCX 26.5 48 Y $4.00
L4558 PCX 26.0 53 N $4.00
L4280 PCX 25.1 103 N $4.00
L4290 PCX 25.1 103 N $4.00
L6644 PCX 25.1 103 N $4.00
L4044 PCX 25.0 105 N $4.00
L6414 PCX 25.0 27 Y $4.00
L7266 PCX 25.0 44 N $4.00
L8104 PCX 25.0 160 N $4.00
L12102 PCX 24.8 34 N $4.00
L8080 PCX 24.5 70 Y $4.00
L4442 PCX 24.0 45 N $4.00
L4651 PCX 24.0 61 Y $4.00
L8101 PCX 23.5 62 Y $4.00
L4460 PCX 23.0 45 N $4.00
L5385 PCX 23.0 41 Y $4.00
L6297 PCX 23.0 54 Y $4.00
L6299 PCX 23.0 46 Y $4.00
L7330 PCX 22.9 85 Y $4.00
L5242 PCX 22.5 49 Y $4.00
L4647 PCX 22.3 59 N $4.00
L6392 PCX 22.3 103 Y $4.00
L4443 PCX 22.0 39 N $4.00
L5400 PCX 21.5 54 Y $4.00
L6235 PCX 21.0 51 Y $4.00
L6424 PCX 20.9 74 Y $4.00
L4459 PCX 20.1 308 N $4.00
L4425 PCX 20.0 40 Y $4.00
L4570 PCX 19.9 45 N $4.00
L4536 PCX 19.8 40 N $4.00
L4590 PCX 19.8 40 N $4.00
L4710 PCX 19.8 44 N $4.00
L5518 PCX 19.7 -15 Y $4.00
L5936 PCX 19.7 316 N $4.00
L5384 PCX 19.5 32 Y $4.00
L5634 PCX 19.5 103 N $4.00
L5942 PCX 19.3 46 Y $4.00
L5110 PCX 19.1 51 Y $4.00
L8085 PCX 19.0 31 Y $4.00
L4567 PCX 18.7 36 N $4.00
L6351 PCX 18.5 39 Y $4.00
L4435 PCX 18.2 108 Y $4.00
L6263 PCX 18.2 28 Y $4.00
L5112 PCX 18.0 14 Y $4.00
L4453 PCX 17.8 80 N $4.00
L7267 PCX 17.5 53 N $4.00
L4464 PCX 16.9 25 Y $4.00
L4472 PCX 16.7 80 N $4.00
L4518 PCX 16.7 80 N $4.00
L4523 PCX 16.7 80 Y $4.00
L4601 PCX 16.7 82 Y $4.00
L4641 PCX 16.7 80 N $4.00
L4644 PCX 16.7 80 Y $4.00
L6268 PCX 16.7 40 Y $4.00
L4045 PCX 16.6 80 Y $4.00
L5142 PCX 16.5 39 Y $4.00
L5127 PCX 16.3 36 Y $4.00
L5904 PCX 16.1 75 Y $4.00
L6234 PCX 16.1 35 Y $4.00
L12082 PCX 16.0 37 N $4.00
L4602 PCX 16.0 89 Y $4.00
L4603 PCX 16.0 44 Y $4.00
L5171 PCX 16.0 31 Y $4.00
L8083 PCX 16.0 32 Y $4.00
L8100 PCX 16.0 26 Y $4.00
L8111 PCX 16.0 35 N $4.00
L5659 PCX 15.7 25 Y $4.00
L4110 PCX 15.5 27 N $4.00
L4456 PCX 15.5 26 Y $4.00
L4431 PCX 15.3 71 N $4.00
L4364 PCX 15.2 21 Y $4.00
L4424 PCX 15.2 80 Y $4.00
L4531 PCX 15.2 82 Y $4.00
L6001 PCX 15.2 25 Y $4.00
L4564 PCX 15.0 25 N $4.00
L4579 PCX 15.0 33 N $4.00
L4583 PCX 15.0 33 N $4.00
L8034 PCX 15.0 80 Y $4.00
L8116 PCX 15.0 51 N $4.00
L5173 PCX 14.8 38 Y $4.00
L6310 PCX 14.5 23 Y $4.00
L4553 PCX 14.4 26 N $4.00
L6271 PCX 14.4 23 Y $4.00
L12113 PCX 14.1 36 N $4.00
L4517 PCX 14.0 27 Y $4.00
L5869 PCX 14.0 29 Y $4.00
L5548 PCX 13.3 22 Y $4.00
L5402 PCX 13.2 32 Y $4.00
L2071 PCX 13.0 35 N $4.00
L4444 PCX 13.0 40 N $4.00
L5534 PCX 13.0 25 Y $4.00
L6599 PCX 13.0 27 Y $4.00
L5442 PCX 12.8 112 Y $4.00
L6585 PCX 12.8 23 Y $4.00
L5097 PCX 12.7 16 Y $4.00
L5446 PCX 12.7 17 N $4.00
L5710 PCX 12.7 30 Y $4.00
L5849 PCX 12.5 31 Y $4.00
L5865 PCX 12.5 35 N $4.00
L5883 PCX 12.5 35 Y $4.00
L6649 PCX 12.5 40 Y $4.00
L5403 PCX 12.3 26 Y $4.00
L4554 PCX 12.2 21 N $4.00
L4461 PCX 12.0 21 Y $4.00
L4463 PCX 12.0 20 Y $4.00
L4581 PCX 12.0 39 N $4.00
L4611 PCX 12.0 21 Y $4.00
L6273 PCX 12.0 43 Y $4.00
L7384 PCX 12.0 23 Y $4.00
L7405 PCX 12.0 24 N $4.00
L4467 PCX 11.9 64 Y $4.00
L6269 PCX 11.5 23 N $4.00
L7378 PCX 11.5 20 N $4.00
L4465 PCX 11.4 49 N $4.00
L5859 PCX 11.2 23 Y $4.00
L1820 PCX 11.0 380 N $4.00
L6246 PCX 11.0 74 Y $4.00
L6272 PCX 11.0 38 Y $4.00
L8048 PCX 11.0 539 Y $4.00
L6402 PCX 10.9 34 N $4.00
L4598 PCX 10.7 26 Y $4.00
L5297 PCX 10.7 23 Y $4.00
L5572 PCX 10.0 42 Y $4.00
L5696 PCX 10.0 18 Y $4.00
L8046 PCX 10.0 22 Y $4.00
L8121 PCX 10.0 34 N $4.00
L4428 PCX 9.9 33 N $4.00
L4469 PCX 9.9 33 N $4.00
L7220 PCX 9.9 103 Y $4.00
L4331 PCX 9.5 25 N $4.00
L4367 PCX 9.5 29 N $4.00
L5863 PCX 9.5 19 Y $4.00
L4580 PCX 9.0 17 Y $4.00
L6274 PCX 9.0 21 Y $4.00
L4164 PCX 8.2 19 Y $4.00
L4561 PCX 8.2 19 Y $4.00
L5280 PCX 8.2 16 Y $4.00
L8082 PCX 8.0 65 Y $4.00
L4562 PCX 7.8 129 N $4.00
L5600 PCX 7.8 108 N $4.00
L6302 PCX 7.6 154 Y $4.00
L6420 PCX 7.6 191 Y $4.00
L5841 PCX 7.5 18 Y $4.00
L6279 PCX 7.5 133 Y $4.00
L6207 PCX 7.0 13 Y $4.00
L6396 PCX 7.0 27 Y $4.00
L6486 PCX 7.0 111 Y $4.00
L5598 PCX 6.5 14 Y $4.00
L5157 PCX 6.3 12 Y $4.00
L4565 PCX 5.6 52 Y $4.00
L6303 PCX 5.6 29 Y $4.00
L12158 PCX 4.8 4 N $4.00
Thanks again!
Apollo Full-Page Handheld Magnifier, Full Page High Power Magnifier, 8-1/2"x12"x1/8", 2X POWER
Apollo's high power magnifier is great for up-close viewing of fine print in stock listings, newspapers, maps, computer printouts, photographs, drawings and all fine prints. Manufactured with shatterproof, scratch resistant, optical-grade acrylic lenses. 8 1/2" x 11" 2X lens enlarges an entire page all at once. Designed to provide years of reliable, distortion-free performance. Made of rigid acrylic for easy handling.
2X Power Magnification;Clear.
They didnt know the Fl, but the description says : 2X
1) IS IT POSSIBLE TO FIND THE FL IF YOU ONLY KNOW THE MAG. POWER? IF NOT, THEN WHAT DOES 2X MEAN?
Id like to add a precondenser lens, coz it willl increase the brightness a lot. As I said, Heat is not a problem, so I dont need pyrex or something like that. Its just I dont have any idea about which one to buy, of course it must be a PCX , but thats all I know.
This is the list from surplusshed (huge 🙂 ),
2) COULD YOU TELL ME WHICH ONE MIGHT WORK BEST WITH MY SETUP? (LETS SAY I USE SETUP #2).
The diameter of the reflector is 140mm, and as a true sphere, its FL is 70mm. The lamp arc is 40mm. And the distance from the lamp arc to the outer envelope of the bulb is 45mm.
Diameter FL Coated
mm mm
L7374 PCX 82.0 143 N $4.00
L7396 PCX 81.0 222 N $4.00
L5091 PCX 66.0 139 Y $4.00
L8008 PCX 65.3 129 Y $4.00
L8000 PCX 65.2 129 Y $4.00
L8006 PCX 63.6 308 N $4.00
L8005 PCX 63.5 114 N $4.00
L4298 PCX 59.7 62 N $4.00
L6223 PCX 56.0 174 Y $4.00
L4101 PCX 52.6 80 Y $4.00
L4336 PCX 52.5 80 Y $4.00
L6260 PCX 51.5 103 N $4.00
L7387 PCX 50.0 114 N $4.00
L8115 PCX 48.0 82 Y $4.00
L4521 PCX 47.6 154 N $4.00
L4307 PCX 46.0 62 Y $4.00
L5266 PCX 44.0 80 Y $4.00
L5367 PCX 44.0 80 Y $4.00
L8058 PCX 42.5 181 Y $4.00
L7068 PCX 42.4 -108 Y $4.00
L4548 PCX 42.2 79 N $4.00
L8097 PCX 42.0 143 Y $4.00
L7391 PCX 41.0 82 N $4.00
L4074 PCX 38.8 62 Y $4.00
L5015 PCX 38.8 69 Y $4.00
L5705 PCX 38.0 101 Y $4.00
L5193 PCX 37.5 68 Y $4.00
L5340 PCX 37.5 68 Y $4.00
L5722 PCX 37.5 65 Y $4.00
L5853 PCX 37.2 53 Y $4.00
L5004 PCX 36.8 390 Y $4.00
L5114 PCX 36.0 131 N $4.00
L4368 PCX 35.6 286 Y $4.00
L5203 PCX 35.0 41 Y $4.00
L8081 PCX 35.0 103 Y $4.00
L8110 PCX 35.0 57 Y $4.00
L6239 PCX 34.9 40 Y $4.00
L6435 PCX 34.9 211 Y $4.00
L6434 PCX 34.7 103 Y $4.00
L5064 PCX 34.5 66 Y $4.00
L5072 PCX 34.5 87 Y $4.00
L4369 PCX 32.5 308 Y $4.00
L6222 PCX 32.1 143 Y $4.00
L6661 PCX 32.0 286 N $4.00
L4662 PCX 31.0 191 N $4.00
L5948 PCX 31.0 54 Y $4.00
L4522 PCX 30.0 53 Y $4.00
L4534 PCX 30.0 93 N $4.00
L6181 PCX 30.0 81 Y $4.00
L6437 PCX 29.0 100 N $4.00
L6436 PCX 28.9 50 N $4.00
L6200 PCX 28.5 68 Y $4.00
L5956 PCX 28.1 561 Y $4.00
L2179 PCX 28.0 59 Y $4.00
L5086 PCX 27.0 53 Y $4.00
L6416 PCX 27.0 33 Y $4.00
L7383 PCX 27.0 32 N $4.00
L5062 PCX 26.5 48 Y $4.00
L4558 PCX 26.0 53 N $4.00
L4280 PCX 25.1 103 N $4.00
L4290 PCX 25.1 103 N $4.00
L6644 PCX 25.1 103 N $4.00
L4044 PCX 25.0 105 N $4.00
L6414 PCX 25.0 27 Y $4.00
L7266 PCX 25.0 44 N $4.00
L8104 PCX 25.0 160 N $4.00
L12102 PCX 24.8 34 N $4.00
L8080 PCX 24.5 70 Y $4.00
L4442 PCX 24.0 45 N $4.00
L4651 PCX 24.0 61 Y $4.00
L8101 PCX 23.5 62 Y $4.00
L4460 PCX 23.0 45 N $4.00
L5385 PCX 23.0 41 Y $4.00
L6297 PCX 23.0 54 Y $4.00
L6299 PCX 23.0 46 Y $4.00
L7330 PCX 22.9 85 Y $4.00
L5242 PCX 22.5 49 Y $4.00
L4647 PCX 22.3 59 N $4.00
L6392 PCX 22.3 103 Y $4.00
L4443 PCX 22.0 39 N $4.00
L5400 PCX 21.5 54 Y $4.00
L6235 PCX 21.0 51 Y $4.00
L6424 PCX 20.9 74 Y $4.00
L4459 PCX 20.1 308 N $4.00
L4425 PCX 20.0 40 Y $4.00
L4570 PCX 19.9 45 N $4.00
L4536 PCX 19.8 40 N $4.00
L4590 PCX 19.8 40 N $4.00
L4710 PCX 19.8 44 N $4.00
L5518 PCX 19.7 -15 Y $4.00
L5936 PCX 19.7 316 N $4.00
L5384 PCX 19.5 32 Y $4.00
L5634 PCX 19.5 103 N $4.00
L5942 PCX 19.3 46 Y $4.00
L5110 PCX 19.1 51 Y $4.00
L8085 PCX 19.0 31 Y $4.00
L4567 PCX 18.7 36 N $4.00
L6351 PCX 18.5 39 Y $4.00
L4435 PCX 18.2 108 Y $4.00
L6263 PCX 18.2 28 Y $4.00
L5112 PCX 18.0 14 Y $4.00
L4453 PCX 17.8 80 N $4.00
L7267 PCX 17.5 53 N $4.00
L4464 PCX 16.9 25 Y $4.00
L4472 PCX 16.7 80 N $4.00
L4518 PCX 16.7 80 N $4.00
L4523 PCX 16.7 80 Y $4.00
L4601 PCX 16.7 82 Y $4.00
L4641 PCX 16.7 80 N $4.00
L4644 PCX 16.7 80 Y $4.00
L6268 PCX 16.7 40 Y $4.00
L4045 PCX 16.6 80 Y $4.00
L5142 PCX 16.5 39 Y $4.00
L5127 PCX 16.3 36 Y $4.00
L5904 PCX 16.1 75 Y $4.00
L6234 PCX 16.1 35 Y $4.00
L12082 PCX 16.0 37 N $4.00
L4602 PCX 16.0 89 Y $4.00
L4603 PCX 16.0 44 Y $4.00
L5171 PCX 16.0 31 Y $4.00
L8083 PCX 16.0 32 Y $4.00
L8100 PCX 16.0 26 Y $4.00
L8111 PCX 16.0 35 N $4.00
L5659 PCX 15.7 25 Y $4.00
L4110 PCX 15.5 27 N $4.00
L4456 PCX 15.5 26 Y $4.00
L4431 PCX 15.3 71 N $4.00
L4364 PCX 15.2 21 Y $4.00
L4424 PCX 15.2 80 Y $4.00
L4531 PCX 15.2 82 Y $4.00
L6001 PCX 15.2 25 Y $4.00
L4564 PCX 15.0 25 N $4.00
L4579 PCX 15.0 33 N $4.00
L4583 PCX 15.0 33 N $4.00
L8034 PCX 15.0 80 Y $4.00
L8116 PCX 15.0 51 N $4.00
L5173 PCX 14.8 38 Y $4.00
L6310 PCX 14.5 23 Y $4.00
L4553 PCX 14.4 26 N $4.00
L6271 PCX 14.4 23 Y $4.00
L12113 PCX 14.1 36 N $4.00
L4517 PCX 14.0 27 Y $4.00
L5869 PCX 14.0 29 Y $4.00
L5548 PCX 13.3 22 Y $4.00
L5402 PCX 13.2 32 Y $4.00
L2071 PCX 13.0 35 N $4.00
L4444 PCX 13.0 40 N $4.00
L5534 PCX 13.0 25 Y $4.00
L6599 PCX 13.0 27 Y $4.00
L5442 PCX 12.8 112 Y $4.00
L6585 PCX 12.8 23 Y $4.00
L5097 PCX 12.7 16 Y $4.00
L5446 PCX 12.7 17 N $4.00
L5710 PCX 12.7 30 Y $4.00
L5849 PCX 12.5 31 Y $4.00
L5865 PCX 12.5 35 N $4.00
L5883 PCX 12.5 35 Y $4.00
L6649 PCX 12.5 40 Y $4.00
L5403 PCX 12.3 26 Y $4.00
L4554 PCX 12.2 21 N $4.00
L4461 PCX 12.0 21 Y $4.00
L4463 PCX 12.0 20 Y $4.00
L4581 PCX 12.0 39 N $4.00
L4611 PCX 12.0 21 Y $4.00
L6273 PCX 12.0 43 Y $4.00
L7384 PCX 12.0 23 Y $4.00
L7405 PCX 12.0 24 N $4.00
L4467 PCX 11.9 64 Y $4.00
L6269 PCX 11.5 23 N $4.00
L7378 PCX 11.5 20 N $4.00
L4465 PCX 11.4 49 N $4.00
L5859 PCX 11.2 23 Y $4.00
L1820 PCX 11.0 380 N $4.00
L6246 PCX 11.0 74 Y $4.00
L6272 PCX 11.0 38 Y $4.00
L8048 PCX 11.0 539 Y $4.00
L6402 PCX 10.9 34 N $4.00
L4598 PCX 10.7 26 Y $4.00
L5297 PCX 10.7 23 Y $4.00
L5572 PCX 10.0 42 Y $4.00
L5696 PCX 10.0 18 Y $4.00
L8046 PCX 10.0 22 Y $4.00
L8121 PCX 10.0 34 N $4.00
L4428 PCX 9.9 33 N $4.00
L4469 PCX 9.9 33 N $4.00
L7220 PCX 9.9 103 Y $4.00
L4331 PCX 9.5 25 N $4.00
L4367 PCX 9.5 29 N $4.00
L5863 PCX 9.5 19 Y $4.00
L4580 PCX 9.0 17 Y $4.00
L6274 PCX 9.0 21 Y $4.00
L4164 PCX 8.2 19 Y $4.00
L4561 PCX 8.2 19 Y $4.00
L5280 PCX 8.2 16 Y $4.00
L8082 PCX 8.0 65 Y $4.00
L4562 PCX 7.8 129 N $4.00
L5600 PCX 7.8 108 N $4.00
L6302 PCX 7.6 154 Y $4.00
L6420 PCX 7.6 191 Y $4.00
L5841 PCX 7.5 18 Y $4.00
L6279 PCX 7.5 133 Y $4.00
L6207 PCX 7.0 13 Y $4.00
L6396 PCX 7.0 27 Y $4.00
L6486 PCX 7.0 111 Y $4.00
L5598 PCX 6.5 14 Y $4.00
L5157 PCX 6.3 12 Y $4.00
L4565 PCX 5.6 52 Y $4.00
L6303 PCX 5.6 29 Y $4.00
L12158 PCX 4.8 4 N $4.00
Thanks again!
I have a couple of those appollo magnifiers seems like the focal is about 12.5" or so.... and actually heat is a problem for the precondensor since it will be only a couple of inches fromthe bulb.... generally the precondenser can be as big as the reflector .....not sure but its a good estimate...but not sure how those will stand up to being only a couple inches away from the bulb,,,,bulbs get up to 300 degress celcius...
picking fresnels
Even the best acrylic fresnels each lose at least 10% of the light, so stacking fresnels to get the right focal lengths is not ideal. They also tend to pass the most light when you send the light through with one particular relationship: That is with the lamp arc at the focal length from the smooth side of the fresnel, which makes the light going out the rough side close to parallel. Or in the case of the field fresnel, with the light entering in parallel on the rough side and exiting in a cone that converges at the focal length on the smooth side. When you stack fresnels to make a shorter focal length combined condensor fresnel, you lose a lot of light because the angles are so far from the optimal angles.
If the cone of light converges right at the center of the projection lens, then you get most of the light on the screen. If it converges before or after the center of the projection lens, then you lose some (or maybe most) of the light. You can see exactly where it converges by removing the LCD and the projection lens. Turn on the lamp and move a piece of white paper around where the projection lens goes. At some position you should see a focussed image of the lamp arc. You can adjust your lamp to condensor fresnel distance to get the arc image in exactly the right place.
You might think about buying a 200 mm fl fresnel to replace your stacked pair. And maybe get two, so you could use the other one as your field fresnel. Most of the DIY online stores sell them, as well as 3dlens.com. (180 mm fl fresnels would be ideal, if you can find them...Good luck!)
As for picking a pre-condensor lens, try searching this forum for threads on "pre-condensor". There is already a lot of info.
Even the best acrylic fresnels each lose at least 10% of the light, so stacking fresnels to get the right focal lengths is not ideal. They also tend to pass the most light when you send the light through with one particular relationship: That is with the lamp arc at the focal length from the smooth side of the fresnel, which makes the light going out the rough side close to parallel. Or in the case of the field fresnel, with the light entering in parallel on the rough side and exiting in a cone that converges at the focal length on the smooth side. When you stack fresnels to make a shorter focal length combined condensor fresnel, you lose a lot of light because the angles are so far from the optimal angles.
If the cone of light converges right at the center of the projection lens, then you get most of the light on the screen. If it converges before or after the center of the projection lens, then you lose some (or maybe most) of the light. You can see exactly where it converges by removing the LCD and the projection lens. Turn on the lamp and move a piece of white paper around where the projection lens goes. At some position you should see a focussed image of the lamp arc. You can adjust your lamp to condensor fresnel distance to get the arc image in exactly the right place.
You might think about buying a 200 mm fl fresnel to replace your stacked pair. And maybe get two, so you could use the other one as your field fresnel. Most of the DIY online stores sell them, as well as 3dlens.com. (180 mm fl fresnels would be ideal, if you can find them...Good luck!)
As for picking a pre-condensor lens, try searching this forum for threads on "pre-condensor". There is already a lot of info.
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