Hi there,
I'm trying to build a DIY projector using an iPad 3 retina panel. I have a hard time deciding which parts I need to make it work. I have few questions If you can answer for me please as I'm completely new to building a projector. I got the idea from Photon3K-First DIY retina projector (2880x1800) - Photo Heavy [REAL] - 15 - Vidéoprojecteurs DIY - FORUM Allinbox He was using a retina Macbook Pro screen there.
For the Retina iPad display. I like the projected image to be 120-140inches width side (Not diagonal). Height can be anything. Project images will have a resolution of 2048 x 1536 pixels which is what iPad 3 screen natively supports. The screen is working cos I have a display adapter from Abusemark for cheap with plugs directly into my graphic card's Displayport.
Mounting location
-------------------
I'm thinking putting the projector on the floor or mount on the ceiling and do keystone correct with tilting the of the lens or LCD depending on the triplet I can find.
Bulb
-----
I have a 35w Xenon and a 100w LED both at 6000k in color temperate. I will text them both to see how each one looks like after I made the initial setup.
Questions
-----------
1. Everyone says .2mm groove pitch is better for Fresnel lens. Is this true? I see lot of .3mm. .2mm are little rare to find.
2. Why do the 2 Fresnel lenses has to be at two different focal lengths?
3. Which is better, split or un-split Fresnel design for sharpness?
3. If I use the following type of lenses, will that work with my screen? These are suggested for a 15 inch widescreen display originally.
Triplet 310-360mm Focal length
Fresnel 330mm Focal length Fresnel
Fresnel 550mm Focal length Fresnel
4. If I can't get these exact focal lengths for the 3 lenses, can you suggest me some focal lengths?
5. Besides the ones I suggested for the focal lengths, is there a more optimal focal lengths can you suggest for my screen size?
6. For keystone correction, I know you can either tilt the Fresnel lens (between LCD and Triplet) or tilt the LCD it self. Which one is better? If I do either, will it make a difference in image sharpness?
7. Besides Optolife (China) where else can you get lenses cheap in US? I've already checked and asked individual sellers on both Amazon and eBay no one has Fresnel lenses at .2mm besides Optolife and 2 more online retailers that are outside of US. Their lens prices are good but shipping is a lot for me on my current budget.
Thank you very much for your time.
I'm trying to build a DIY projector using an iPad 3 retina panel. I have a hard time deciding which parts I need to make it work. I have few questions If you can answer for me please as I'm completely new to building a projector. I got the idea from Photon3K-First DIY retina projector (2880x1800) - Photo Heavy [REAL] - 15 - Vidéoprojecteurs DIY - FORUM Allinbox He was using a retina Macbook Pro screen there.
For the Retina iPad display. I like the projected image to be 120-140inches width side (Not diagonal). Height can be anything. Project images will have a resolution of 2048 x 1536 pixels which is what iPad 3 screen natively supports. The screen is working cos I have a display adapter from Abusemark for cheap with plugs directly into my graphic card's Displayport.
Mounting location
-------------------
I'm thinking putting the projector on the floor or mount on the ceiling and do keystone correct with tilting the of the lens or LCD depending on the triplet I can find.
Bulb
-----
I have a 35w Xenon and a 100w LED both at 6000k in color temperate. I will text them both to see how each one looks like after I made the initial setup.
Questions
-----------
1. Everyone says .2mm groove pitch is better for Fresnel lens. Is this true? I see lot of .3mm. .2mm are little rare to find.
2. Why do the 2 Fresnel lenses has to be at two different focal lengths?
3. Which is better, split or un-split Fresnel design for sharpness?
3. If I use the following type of lenses, will that work with my screen? These are suggested for a 15 inch widescreen display originally.
Triplet 310-360mm Focal length
Fresnel 330mm Focal length Fresnel
Fresnel 550mm Focal length Fresnel
4. If I can't get these exact focal lengths for the 3 lenses, can you suggest me some focal lengths?
5. Besides the ones I suggested for the focal lengths, is there a more optimal focal lengths can you suggest for my screen size?
6. For keystone correction, I know you can either tilt the Fresnel lens (between LCD and Triplet) or tilt the LCD it self. Which one is better? If I do either, will it make a difference in image sharpness?
7. Besides Optolife (China) where else can you get lenses cheap in US? I've already checked and asked individual sellers on both Amazon and eBay no one has Fresnel lenses at .2mm besides Optolife and 2 more online retailers that are outside of US. Their lens prices are good but shipping is a lot for me on my current budget.
Thank you very much for your time.
Hope it's not too late for a reply 🙂
1. I've only ever seen .2mm and .5mm groove pitch fresnel lenses. The fundamental difference between the two is the .2mm lens has more grooves per inch/mm which equates to a cleared picture as opposed to the .5mm one. However I haven't seen this proven anywhere, but the .5mm lens should let more light through as there are less rings per inch thus less restrictions for light to pass through.
If using a split design then for the fresnel lens that goes in front of the LCD I would definitely use a .2mm as it's finer and the rings are less intrusive when focusing on the LCD.
2. They don't have to be. Commonly a 220mm FL for the collector fresnel is used because this FL is sort of a sweet-spot so that you gather as much light as possible from your lamp but also you don't get a ridiculous amount of vignetting in the corners. 330mm are also common as collector fresnels as they give much better light uniformity in or near the corners by sacrificing overall brightness.
It does not matter what focal length you use for the collector lens, up to you. What really matters is you match your field fresnel focal length to your projection lens focal length as best as you can.
3. Unsplit end of.
3. The combination of lenses you have there would only work if you use the 550mm fresnel as the collector and the 330mm as the field which would match up with the projection lens. Using the 550mm as the collector in my opinion will give you fantastic light uniformity but you'll be losing a lot of light.
I would suggest using the 330 as collector and 550 as field but you would need a new lens in the range of 500 - 600 mm focal length to make it work.
4. See number 3
5. Use the following online calculator to work out what lenses you need
ALLINBOX
6. I don't think tilting the LCD itself will actually give you keystone correction, as far as I know you can only get keystone with a split design by tilting the front fresnel lens.
7. afraid can't help you there, I'm in the UK and there's a couple of sellers here that sell them on ebay, that's where I got mine.
1. I've only ever seen .2mm and .5mm groove pitch fresnel lenses. The fundamental difference between the two is the .2mm lens has more grooves per inch/mm which equates to a cleared picture as opposed to the .5mm one. However I haven't seen this proven anywhere, but the .5mm lens should let more light through as there are less rings per inch thus less restrictions for light to pass through.
If using a split design then for the fresnel lens that goes in front of the LCD I would definitely use a .2mm as it's finer and the rings are less intrusive when focusing on the LCD.
2. They don't have to be. Commonly a 220mm FL for the collector fresnel is used because this FL is sort of a sweet-spot so that you gather as much light as possible from your lamp but also you don't get a ridiculous amount of vignetting in the corners. 330mm are also common as collector fresnels as they give much better light uniformity in or near the corners by sacrificing overall brightness.
It does not matter what focal length you use for the collector lens, up to you. What really matters is you match your field fresnel focal length to your projection lens focal length as best as you can.
3. Unsplit end of.
3. The combination of lenses you have there would only work if you use the 550mm fresnel as the collector and the 330mm as the field which would match up with the projection lens. Using the 550mm as the collector in my opinion will give you fantastic light uniformity but you'll be losing a lot of light.
I would suggest using the 330 as collector and 550 as field but you would need a new lens in the range of 500 - 600 mm focal length to make it work.
4. See number 3
5. Use the following online calculator to work out what lenses you need
ALLINBOX
6. I don't think tilting the LCD itself will actually give you keystone correction, as far as I know you can only get keystone with a split design by tilting the front fresnel lens.
7. afraid can't help you there, I'm in the UK and there's a couple of sellers here that sell them on ebay, that's where I got mine.
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