i'need your's help to told me how can i'replace the Fresnel Lens
with onter one can i'replace it with
1-minus lens
2-overhead pj lens
3-plus lens

I suspect English isn't your primary language. What do you have and what would like to do?
If you could provide the focal length(s) and physical size(s) of the lenses you have that would be helpful.

sorry for my poor language

my problem that i'can't buy the Fresnel Lens online or by other way i'cant have it

all that i'have this three lens if i'can do the pj with this three lens

that will be very good

i'have overhead projector lens ,four fans,linear halogen lamp "300w,tow pieces of Tempered Glass

and i'can get the -minus lens or -plus lens
the plus lens that i'hve is 130mm and other sizes if it will be helpful
and the minus lens that i'have is 50mm
that all i'have

If all of the lenes are from the same overhead projector, you should be able to make an LCD projector from it.

When you say "minus lens" and "plus lens"... Do you mean the fresnels?

So from what I can figure....

He does not have any fresnels, and can't buy them anywhere. He has 1 big lens at 130mm, 1 small lens at 50mm, and one overhead projector lens. It sounds like he's asking if he can replace the fresnels with one of these instead.

Dragonfire, if that is what you mean, then the answer is no. The fresnels have to be fresnels, no substitutions. The lenses you have can't be used to replace the fresnels. Also, if you are fluent in another language, check out the global forum. Someone there may be able to explain things to you better than I can. Hope I have helped somewhat.

mr.DeathRay64 i'mean by saying "minus lens" and "plus lens" the lenses


mr.pvfjr thank you for your answer but can any one explain to me by easy way

what the fresnels do ?

i'mean after i'put the fresnels behind the lcd what the fresnels do ?

if it maximize the light then i'can replace it

tell me what the fresnels do and i'will find a solution

There are two optical systems in a PJ that work in conjunction with each other.
The projection lens magnifies the image created by the LCD and displays it on
the screen. The pair of fresnel lenses bend the light from the lamp, send it
through the LCD and guide it into the projection lens at the proper angles to
make the displayed image brighter and watchable.