I mean, I had been working on this project day & night for over 2 & 1/2 months... and now since it is signed off I have got nothing to do.... except enjoying the movies on BIG screen.
pollok said:
Yes, Pollok.... I did that. Have also checked TV on the projector. But you know what... our living room is smaller than the bedroom, and there's no space there to put the screen. So we use the projector in our bedroom so that we could get a big screen, and also that we can watch the movies lying down on the bed.
Besides this, the incoming TV cable (from the operator) is not big enough to stretch inside the bedroom. I'll require to make a long extn. cable so that we can watch TV also on projector. But actually speaking, we do not want to watch TV programs on the big screen... except for the Cricket matches... as you said it, ilango_slk.
GOOD SHOW MAKS! Congratulations
The Projector looks good and the projection is also nice and clear.
I recently picked up a root (chinese) dvd player which plays divx files and also has a USB input .This gives me the flexibility of wathing hi res images from my comp directly on my big screen without having to burn discs!
The Projector looks good and the projection is also nice and clear.
I recently picked up a root (chinese) dvd player which plays divx files and also has a USB input .This gives me the flexibility of wathing hi res images from my comp directly on my big screen without having to burn discs!
Maks, Budhi,
There is a slight hiccup in my project. I did a rough trial yesterday, and found that the triplet lenses I bought in Chennai are not working with this pj. They were taken from old LCD pjs, and so I thought they will work here. But these lenses have to be kept very near the lcd to pick up the image, and since it is very close to the lcd, it is not covering the full lcd screen. Only a part of it gets projected.
I took the condenser lens and tried to project with it (inverted - the curved surface towards the lcd, and flat surface towards the wall. THe other way didn't work), and got a very big projected image of the entire screen, but with blurry edges. So I have moved into pause mode for now till I get the right triplet. I have written to Lensel, and am waiting for their reply.
Pollok
There is a slight hiccup in my project. I did a rough trial yesterday, and found that the triplet lenses I bought in Chennai are not working with this pj. They were taken from old LCD pjs, and so I thought they will work here. But these lenses have to be kept very near the lcd to pick up the image, and since it is very close to the lcd, it is not covering the full lcd screen. Only a part of it gets projected.
I took the condenser lens and tried to project with it (inverted - the curved surface towards the lcd, and flat surface towards the wall. THe other way didn't work), and got a very big projected image of the entire screen, but with blurry edges. So I have moved into pause mode for now till I get the right triplet. I have written to Lensel, and am waiting for their reply.
Pollok
Thanks Maks for your kind words.
The dvd player was from indiatimes shopping, company called Root .But I am not really happy with it as the mechanism is rather flimsy and so I think I will be returning it.
It was all of Rs 2500/- so I am not too worried!
Pollok
Your lens seems to be a mismatch , you will need to add another lens to bring the size down or work with a new lens alltogether. "Tgreenwood" has some excellent optics solutions on this site search for them.basically you have to achieve approx 80-100 Inch projection andacross a common room of approx 10 to 12 ft in length a 300 mm lens is usually great for this.
You are right about the curved side to lcd part.
try putting thr lens in afocusing tube as this improves contrast and also play with an aperture disc(a black card with a hole about 2 inch dia in the middle) placed next to the lens improves sharpness but also eats some amount of light.
the following text is from tgreenwood it helped me a lot.
Decide on the final focal length of your projection lens, the focal length you need to get the size projection you want. As an example, lets say you need a 300mm EFL projection lens. To find out what focal length the two individual lens elements have to be, multiply the EFL by 1.71. So, your two lenses have to be 513mm fl lenses. (get reasonably close anyway). To find out how far apart to mount the two lenses in the mounting tube, divide the EFL by 2. So they need to be mounted 150mm apart. Now you have a 300mm EFL symmetrical duplet projection lens.
Using the same calculation, if you need a 6 inch EFL projection lens,
The two lenses inside need to be 10.26 inch focal length
They need to be mounted 3 inches apart.
The field of view on projection lenses made this way is about 30 degrees, so get the biggest diameter lenses you can. Positive meniscus lenses from Rolyn are from about 65mm diameter for the glass ones and about 75mm for the acrylic ones.
Hope this helps you out.
The dvd player was from indiatimes shopping, company called Root .But I am not really happy with it as the mechanism is rather flimsy and so I think I will be returning it.
It was all of Rs 2500/- so I am not too worried!
Pollok
Your lens seems to be a mismatch , you will need to add another lens to bring the size down or work with a new lens alltogether. "Tgreenwood" has some excellent optics solutions on this site search for them.basically you have to achieve approx 80-100 Inch projection andacross a common room of approx 10 to 12 ft in length a 300 mm lens is usually great for this.
You are right about the curved side to lcd part.
try putting thr lens in afocusing tube as this improves contrast and also play with an aperture disc(a black card with a hole about 2 inch dia in the middle) placed next to the lens improves sharpness but also eats some amount of light.
the following text is from tgreenwood it helped me a lot.
Decide on the final focal length of your projection lens, the focal length you need to get the size projection you want. As an example, lets say you need a 300mm EFL projection lens. To find out what focal length the two individual lens elements have to be, multiply the EFL by 1.71. So, your two lenses have to be 513mm fl lenses. (get reasonably close anyway). To find out how far apart to mount the two lenses in the mounting tube, divide the EFL by 2. So they need to be mounted 150mm apart. Now you have a 300mm EFL symmetrical duplet projection lens.
Using the same calculation, if you need a 6 inch EFL projection lens,
The two lenses inside need to be 10.26 inch focal length
They need to be mounted 3 inches apart.
The field of view on projection lenses made this way is about 30 degrees, so get the biggest diameter lenses you can. Positive meniscus lenses from Rolyn are from about 65mm diameter for the glass ones and about 75mm for the acrylic ones.
Hope this helps you out.
pollok said:
Hey Pollok... don't underestimate Budhi... he's a prof. Lensman, man..!!!
Well, before buying a new Triplets, I feel you should try using a defuser between the cond. lens and the objective. It will correct any light discrepancies that's a result of using a cond. lens, and will spread out the light evenly, thus might fix the blur edges problem. However, it will also eat some amount of light. Just give it a try.
I am sure Lensels will not reply you so soon if you have wrote to them as an individual. They responded to my email after 2 & 1/2 months.
pollok said:
Pollok, EFL or Effective Focal Length is what we term as the focal length of a Lens. It the focal lengths of the two or more lens and the spacing between those elements. You can get EFL calculators freely available on the net.
A defuser is not restricted to a certain material. It is used where the light needs to be spread evenly on a given surface. It is used widely from household lightings to movie sets. A softbox which is used in studios is also a kind of defuser (Budhi the Lensman, please correct me if I am wrong). Lexans used as roof tops also serve as defusers. If you have already stripped your LCD, you can find a thin plastic sheet on the backlight. This is also a defuser. It's not completely transperent but a slightly smoky, yet it passes 94% of light (depending upon the quality).
New projector from India !
Here is another pic of the work that has already been done i'm just waiting on y lense everything else is done.http://www.hostclip.com/dl/50f535480cda3e1838e9177d38ff57dd
Here is another pic of the work that has already been done i'm just waiting on y lense everything else is done.http://www.hostclip.com/dl/50f535480cda3e1838e9177d38ff57dd
An externally hosted image should be here but it was not working when we last tested it.
New projector from India !
Sorry guys here is the link http://www.hostclip.com/dl/b3dce095217edb170d29322add07b2e2[/IMG]
Sorry guys here is the link http://www.hostclip.com/dl/b3dce095217edb170d29322add07b2e2[/IMG]
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.