125mm barco lens

[ace3000_1]

i think 26 euros for a big lens is a good price

So do i keep me informed mio and good luck with your projectors.

Trev

[dracul]

Ace, dont you like me anymore?
Can someone answer me please.

[moi]

dracul

biggest is your lens and more light passes through

[dracul]

Yes, that would be true if I had more light to pass through.
But like I said all the light hitting the fresnel is making it to the back and within the 65mm diameter triplet I have now. The hot spot fits well within. So I can have a 500mm diameter triplet and the same amount of light is going to be hitting the back of the triplet. Now I tried using only the 9 inch FL fresnel to focus the light to a 150mm triplet( just round circle on paper) and it works but the fresnel is farther from the light and the hotspot while it is 150mm in diameter, it is dimmer. I am sure it is about the same intensity maybe less since my fresnel is farther from the bulb with this method but I really doubt it is more. There is one other option that seemed to work but its not ideal.
If I place the fresnel at 5 inches from light I can still get a good 150mm diameter hotspot at the FL of the triplet. But at 5 inches my fresnel will not last I dont think even with a 150watt hqi MH.

[moi]

dracul

my technical english is so bad ,i don't understand everything
but i think you're wrong caus you try to see if the ligjht after your fresnel is brighter if it makes a 65mm light circle or a 150mm
at this point the light circle 'll be the same bright
but:

if you have a 30mm proj lens the light 'll be darker than with a 150mm lens( if i understood all i read on this forum)
my first experience was to try to make light pass trough a 15mm camcorder lens and there is no light out (pocket lamp) but the light passes through a 50mm camera lens

bye