So, surplus shed's site says they have the "FUJINON COPY LENS, 290MM FL" in stock now.
What's the pro / con of this copy lens vs. the LL 320mm triplet? The cost savings in the copy lens is nice, but it also looks bigger and bulkier. I'm looking to go the 15" lcd route.
What's the pro / con of this copy lens vs. the LL 320mm triplet? The cost savings in the copy lens is nice, but it also looks bigger and bulkier. I'm looking to go the 15" lcd route.
I have no idea, but I ordered one from them yesterday. My intent is to open it up and learn a little more about lenses.
My guess is that it will be unsuitable for projection, esp. compared to the LL triplet.
Any suggestions on how to dismantle it, and what to look for?
My guess is that it will be unsuitable for projection, esp. compared to the LL triplet.
Any suggestions on how to dismantle it, and what to look for?
should work fine!
Should work great, just the way it is, for a 5" or 7" projector. Try it before you crack it open!
Should work great, just the way it is, for a 5" or 7" projector. Try it before you crack it open!
i think ill still get a triplet.
i have a 5" ps1 screen but soon i am upgrading to a 7 in screen. are the corners going to be dark if i use this lens.
and also. is there another way i can increase the throw distance
i have a 5" ps1 screen but soon i am upgrading to a 7 in screen. are the corners going to be dark if i use this lens.
and also. is there another way i can increase the throw distance
increasing throw distance
Easy: Get a longer focal length projection lens. Then you can move the projector back without getting an image that is too big.
1/focal length = 1/LCD to lens + 1/lens to screen
Magnification = lens to screen / LCD to lens
also Magnification = size of image / size of LCD
That's everything you need to figure out all the measurements for different focal lengths, image sizes, etc.
Easy: Get a longer focal length projection lens. Then you can move the projector back without getting an image that is too big.
1/focal length = 1/LCD to lens + 1/lens to screen
Magnification = lens to screen / LCD to lens
also Magnification = size of image / size of LCD
That's everything you need to figure out all the measurements for different focal lengths, image sizes, etc.
Copy Lens, CRT Lens or Triplet for short throw distance
Hey,
I have a PS1 LCD (5") and my throw distance is going to be 2.4 meters (94.488188976") and I want a 60" projected image but I have a 330 mm FL Triplet (12.992125971") from a 3M 2150 OHP that is going to give me a 32" diagonal size screen.
After doing the maths I Know that the projection lens that I need is a 180 mm FL but I don't know if I there is a copy lens, triplet or a CRT lens with this FL and with a diameter that can project the 5" PS1 LCD or if I must go for a slide projection lens.
In the best case can you show me a lens in the Surplus Shed page that can fit to my projector needs?
I can also make a exchange with some one that has a lens that fit with my project and wants my 3M 330 mm triplet.
Thanks a lot !!
Hey,
I have a PS1 LCD (5") and my throw distance is going to be 2.4 meters (94.488188976") and I want a 60" projected image but I have a 330 mm FL Triplet (12.992125971") from a 3M 2150 OHP that is going to give me a 32" diagonal size screen.
After doing the maths I Know that the projection lens that I need is a 180 mm FL but I don't know if I there is a copy lens, triplet or a CRT lens with this FL and with a diameter that can project the 5" PS1 LCD or if I must go for a slide projection lens.
In the best case can you show me a lens in the Surplus Shed page that can fit to my projector needs?
I can also make a exchange with some one that has a lens that fit with my project and wants my 3M 330 mm triplet.
Thanks a lot !!
I think any of these would work:
simple achromatic doublet 51 mm diameter 180 mm fl $6:
http://www.surplusshed.com/pages/item/l2147.html
wide field objective 43 mm diameter 150 mm fl $5
http://www.surplusshed.com/pages/item/l3027.html
copy lens 40 mm diameter 170 mm fl $6
http://www.surplusshed.com/pages/item/l3297.html
The doublet would give you a color-corrected image of exactly the right size, but it might have some flat field focussing problems, or barrel distortion. So I would go with the copy lens, if you can tolerate a slightly larger image or shorter throw distance. Copy lenses are usually very good for projection, since they have to make good copies with wide flat fields.
I would recommend you use a pair of 220 mm fl fresnels with that lens, both before the LCD about 3.7 cm. That should give you a nice 1:1 image of the lamp arc focussed into the projection lens. As long as your lamp arc is smaller than 40 mm, all the light should end up in the projection lens. If you use that configuration, cut your fresnels wide enough so they light the whole LCD area even with the converging cone of light.
That might make a light cone with the angle too steep for the viewing angle of the LCD. If you find that this gives you dark edges, then you could try changing to a split design with a 180 mm fresnel 10 mm after the LCD.
simple achromatic doublet 51 mm diameter 180 mm fl $6:
http://www.surplusshed.com/pages/item/l2147.html
wide field objective 43 mm diameter 150 mm fl $5
http://www.surplusshed.com/pages/item/l3027.html
copy lens 40 mm diameter 170 mm fl $6
http://www.surplusshed.com/pages/item/l3297.html
The doublet would give you a color-corrected image of exactly the right size, but it might have some flat field focussing problems, or barrel distortion. So I would go with the copy lens, if you can tolerate a slightly larger image or shorter throw distance. Copy lenses are usually very good for projection, since they have to make good copies with wide flat fields.
I would recommend you use a pair of 220 mm fl fresnels with that lens, both before the LCD about 3.7 cm. That should give you a nice 1:1 image of the lamp arc focussed into the projection lens. As long as your lamp arc is smaller than 40 mm, all the light should end up in the projection lens. If you use that configuration, cut your fresnels wide enough so they light the whole LCD area even with the converging cone of light.
That might make a light cone with the angle too steep for the viewing angle of the LCD. If you find that this gives you dark edges, then you could try changing to a split design with a 180 mm fresnel 10 mm after the LCD.
Hi Guy
I followed your recommendation and odrered the 40MM DIAMETER EDNALITE COPY LENS 170 mm FL for US$6 plus shipping (I think I'll pay more for the shipping than for the lens but that's ok). Now I'm waiting for their confirmation email with the final price including shipping cost.
I think I will try your first recommendation for the set up with the two 220 mm FL Fresnels before de LCD hoping not to have dark edges
Thanks a lot
I followed your recommendation and odrered the 40MM DIAMETER EDNALITE COPY LENS 170 mm FL for US$6 plus shipping (I think I'll pay more for the shipping than for the lens but that's ok). Now I'm waiting for their confirmation email with the final price including shipping cost.
I think I will try your first recommendation for the set up with the two 220 mm FL Fresnels before de LCD hoping not to have dark edges
Thanks a lot
try before cutting!
De nada. I think it should all work as I have said, but you should try it on a bench to make sure before you cut the fresnels, etc.
Just use tape, wood blocks, clamps, or whatever to get everything lined up and spaced correctly. Mask the fresnels on all four sides with cardboard, so the clear area in the center is where you think you should cut them. If you can project a good image this way, that tells you all will be well. Then you can put it all in a box, already knowing the correct dimensions.
De nada. I think it should all work as I have said, but you should try it on a bench to make sure before you cut the fresnels, etc.
Just use tape, wood blocks, clamps, or whatever to get everything lined up and spaced correctly. Mask the fresnels on all four sides with cardboard, so the clear area in the center is where you think you should cut them. If you can project a good image this way, that tells you all will be well. Then you can put it all in a box, already knowing the correct dimensions.
try before cutting!
I agree with that, I'll do the tests before cutting the fresnels.
Surpplus Shed has sent me the shipping cost (US$7) and I sent them my paypal so I'll wait for the lens to arrive
Gracias amigo !! 🙂
I agree with that, I'll do the tests before cutting the fresnels.
Surpplus Shed has sent me the shipping cost (US$7) and I sent them my paypal so I'll wait for the lens to arrive
Gracias amigo !! 🙂
My surplusshed Fujinon is due to arrive tomorrow. That's great news that it might work for a small projector, thanks Guy.
I won't have a chance to really experiment much with it until after the weekend, but if anyone wants me to take a measurement or post a photo tomorrow let me know. I'd be happy to.
I won't have a chance to really experiment much with it until after the weekend, but if anyone wants me to take a measurement or post a photo tomorrow let me know. I'd be happy to.
Really quick and easy test
If you have two light sources (ie. flashlights), you can test the field angle of a projection lens:
Put (or hold) the lens at your desired throw distance from a white wall. Then move the two light sources back and forth behind the lens until you get a focussed image on the wall. If the distance between the two light sources is equal to the diagonal measurement of your LCD, and you get a good image of both on the wall, then you know the lens field angle is wide enough for your LCD.
If you have two light sources (ie. flashlights), you can test the field angle of a projection lens:
Put (or hold) the lens at your desired throw distance from a white wall. Then move the two light sources back and forth behind the lens until you get a focussed image on the wall. If the distance between the two light sources is equal to the diagonal measurement of your LCD, and you get a good image of both on the wall, then you know the lens field angle is wide enough for your LCD.
Attachments
Guy you seem quite knowledgeable about lenses and im pretty noob. So i was wondering if http://www.surplusshed.com/pages/item/l3225.html
will work well with a 5" psone lcd. I think im going to use 2 220 fresnels. Any suggestions? If that lens doesnt work ill just get the 290mm fl fujinon instead.
I was also wondering how i should set up the fresnels? Ive seen split designs, and those with both fresnels preceding the LCD. Which would be best for this set up?
will work well with a 5" psone lcd. I think im going to use 2 220 fresnels. Any suggestions? If that lens doesnt work ill just get the 290mm fl fujinon instead.
I was also wondering how i should set up the fresnels? Ive seen split designs, and those with both fresnels preceding the LCD. Which would be best for this set up?
get the Fujinon
If I was trying to build a PSone projector, I would use the Fujinon 290 mm fl copy lens. It is much wider than the Goerz lens you pointed to, so you will get a brighter image. (It is also half the price!) Lots of PSone builders have been happy with this lens.
With a 290 mm fl projection lens, I recommend a non-split design with a 220 (or smaller) fl condensor fresnel and a 330 mm fl field fresnel. Put the fresnels together (ring sides facing each other) about 20 mm before the LCD. Start with the lamp arc at the focal length of the condensor fresnel, and then adjust that distance until you get the lamp's arc image focussed exactly at the center of the projection lens. (This combo of 290 lens with 220 & 330 fresnels is a very standard overhead projector design.)
To calculate exact distances for the different fresnel and lens positions, you have to decide what size image you want, or what the throw distance will be. (Post one of those, if you want some math.) But you can determine all of those distances experimentally by iterating between focussing the screen image (moving the projection lens relative to the LCD), and then adjusting the focus of the arc image (moving the field fresnel relative to the projection lens, or moving the lamp arc).
Just FIY: The only reason to use a split design is so you can do optical keystone correction. The image is better with a non-split design.
If I was trying to build a PSone projector, I would use the Fujinon 290 mm fl copy lens. It is much wider than the Goerz lens you pointed to, so you will get a brighter image. (It is also half the price!) Lots of PSone builders have been happy with this lens.
With a 290 mm fl projection lens, I recommend a non-split design with a 220 (or smaller) fl condensor fresnel and a 330 mm fl field fresnel. Put the fresnels together (ring sides facing each other) about 20 mm before the LCD. Start with the lamp arc at the focal length of the condensor fresnel, and then adjust that distance until you get the lamp's arc image focussed exactly at the center of the projection lens. (This combo of 290 lens with 220 & 330 fresnels is a very standard overhead projector design.)
To calculate exact distances for the different fresnel and lens positions, you have to decide what size image you want, or what the throw distance will be. (Post one of those, if you want some math.) But you can determine all of those distances experimentally by iterating between focussing the screen image (moving the projection lens relative to the LCD), and then adjusting the focus of the arc image (moving the field fresnel relative to the projection lens, or moving the lamp arc).
Just FIY: The only reason to use a split design is so you can do optical keystone correction. The image is better with a non-split design.
the 290mm lens looks likt it would rock for a smaller projection. I got pretty amazing FOV on mine (over 13" at FL), however it gets a little dim at the corners. Here's a shot from my LCD testbed, it's a 10"x10" fresnel with a large LCD panel in front of it... the focused/lighted image is about 9.25"x9.25". Sorry for the lack of light uniformity, but I think it's due to the crappy OHP fresnels I'm using.
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Hi Shagman,
Thats a good way to do the pics. I'll have to try that.
Are you using a spherical reflector? An elliptical will give more even light.
If you can find a double concave and a plano-convex with about the same curvature you could use it with your triplet. to turn it into a telephoto type lens. I'm going to try it myself as soon as i can make something to hold them all.
Thats a good way to do the pics. I'll have to try that.
Are you using a spherical reflector? An elliptical will give more even light.
If you can find a double concave and a plano-convex with about the same curvature you could use it with your triplet. to turn it into a telephoto type lens. I'm going to try it myself as soon as i can make something to hold them all.
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