lumenlab engine told you 7" for a 327mm focal lengh???????
it is not posible.
you need to have shorter focal projection lens if you want it closer from lcd
it is not posible.
you need to have shorter focal projection lens if you want it closer from lcd
Must be me being wrong then!
Can you explain to me how you got that calculation so I know where i'm going wrong - I'm using the formula 1/f=1/p+1/q
Also, if I want to shorten that length then what lens would you recommend?
Can you explain to me how you got that calculation so I know where i'm going wrong - I'm using the formula 1/f=1/p+1/q
Also, if I want to shorten that length then what lens would you recommend?
In fact I just placed the triplet where your fresnell is focusing the light.
If you let me know your throw i can tell you the exact triplet position using that formula.
If you let me know your throw i can tell you the exact triplet position using that formula.
My throw distance is 10ft or as close as I can to it!
Itching to order all my parts but I want to make sure my measurments are good before I go spending!
Itching to order all my parts but I want to make sure my measurments are good before I go spending!
Now i see how you did it! Thanks!
14 inches is way too long for the size of build i was planning
Is there any way to reduce this length?
Maybe by placing the mirror in the path of the LCD instead of the path of the light?
14 inches is way too long for the size of build i was planning
Is there any way to reduce this length?
Maybe by placing the mirror in the path of the LCD instead of the path of the light?
you can do whatever bends on mirrors as long as the absolute distance is 14.4".
I guess you didn´t consider at all the projected image size, who cares 😀.
2 questions;
1)you have only 1 fresnell?
2)who told you to buy 327mm triplet?
shorter focal triplet will give you larger image size at your desired 10' trhow. I think it was this thread where there are some xplanations by renan. Use them. to determine your setup. Good luck
I guess you didn´t consider at all the projected image size, who cares 😀.
2 questions;
1)you have only 1 fresnell?
2)who told you to buy 327mm triplet?
shorter focal triplet will give you larger image size at your desired 10' trhow. I think it was this thread where there are some xplanations by renan. Use them. to determine your setup. Good luck
as for the 327mm triplet, I was going off the one from LumenLab which has been used on another PJ build i saw (Can't remember which one)
As for the fresnels, I am just about to look into a way of positioning the fresnels, can someone explain which is the best way of positioning fresnels ie; one each side? One near one far? Unsplit?
I have revised the PJ plan slightly and moved the LCD closer to the lamp, this way I can easily achieve the 14" distance needed between the LCD and lens - Am I right?
I'm still struggling with that calculation, i'm really poor at maths so someone is going to have to explain it a bit better for me! This is what I get a LL's calculator...
Where am i going wrong?
As for the fresnels, I am just about to look into a way of positioning the fresnels, can someone explain which is the best way of positioning fresnels ie; one each side? One near one far? Unsplit?
I have revised the PJ plan slightly and moved the LCD closer to the lamp, this way I can easily achieve the 14" distance needed between the LCD and lens - Am I right?
An externally hosted image should be here but it was not working when we last tested it.
I'm still struggling with that calculation, i'm really poor at maths so someone is going to have to explain it a bit better for me! This is what I get a LL's calculator...
An externally hosted image should be here but it was not working when we last tested it.
Where am i going wrong?
this calculation is perfect. But you have to understand what does it mean;
IF you use a 7.85" focal projection lens, then you will have 100" at 10' trhow. But the lens you have is not 7.85" but 327mm am I wrong?
also, having a 7.86" focal lengh, it doesn´t mean it goes at 7.85" from LCD, work it out with the equation you posted again.
Not to forget, your 330mm fresnells won´t work for such a short projection lens, they have to match the focals so the triplet is roughly placed at fresnell lens focal point.
IF you use a 7.85" focal projection lens, then you will have 100" at 10' trhow. But the lens you have is not 7.85" but 327mm am I wrong?
also, having a 7.86" focal lengh, it doesn´t mean it goes at 7.85" from LCD, work it out with the equation you posted again.
Not to forget, your 330mm fresnells won´t work for such a short projection lens, they have to match the focals so the triplet is roughly placed at fresnell lens focal point.
I understand now! I was misunderstanding the end result of the calculation!
SO with this calculation in mind, what would be the best PJ lens and fresenel set?
And how far would the lens need to be away from the lcd?
Sorry to ask others to work it out but my maths is awful!
SO with this calculation in mind, what would be the best PJ lens and fresenel set?
And how far would the lens need to be away from the lcd?
Sorry to ask others to work it out but my maths is awful!
If you order a 200mm fl set of fresnels from 3dlens.com and go to american science and surplus and order the 7.8" fl lens(www.sciplus.com Lens# 69057 in the list of lenses). You will get a pretty good size screen from around 10ft. It is what I am going with. I have not finished it yet, but I have some pretty good preliminary results. Make sure you get a good condensor and reflector setup. Everything must be set to its stated focal length - give or take a few mm's. I have been able to get a small straight thru design using these optics. The lens's fl is too tight to use a mirror as far as my measurements are concerned. See my PLOG.Steamer's 7" Lilliput Projector. I just ordered another Lilli so the project will be picking back up soon.
Hope this helps.
Steamerwww.sciplus.com
Hope this helps.
Steamerwww.sciplus.com
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