ok, my question this time is what is better, 1 or 2 fresnal lenses? i'm using a 15"stripped computer lcd and want to put it into an enclosure such as one of the mk's on the diypc's site...i am about to order a 400w MH setup for lighting. right now i am just using my OHP and i am quite happy with the results. will using the OHP's fresnal and projection lens work well for an enclosure setup?
last question, my lcd panel is like 9.25 x 12.25 or something like that, will the 12 x 12 mirror used in these designs be large enough? and being that it's a 400w light setup do i need a condensor?thanks
p.s. sorry for all of the questions, but i'm trying to make my final decisions and order all of my remaning parts
last question, my lcd panel is like 9.25 x 12.25 or something like that, will the 12 x 12 mirror used in these designs be large enough? and being that it's a 400w light setup do i need a condensor?thanks
p.s. sorry for all of the questions, but i'm trying to make my final decisions and order all of my remaning parts
i'm just now learing about this stuff too.
and apparently, the ohp's fresnals are actually two sandwiched together!!!
so you either use them that way, with two sandwiched fresnels between the reflected light and the lcd...
or if you use the more complicated lcd between the two fresnels for more focusing control......
and apparently, the ohp's fresnals are actually two sandwiched together!!!
so you either use them that way, with two sandwiched fresnels between the reflected light and the lcd...
or if you use the more complicated lcd between the two fresnels for more focusing control......
concerning the fresnel:
you need a condensor fresnel which give homogeneous lighting to your lcd from your (pseudo)ponctual ligh source.
you need a field fresnel which send all the ligh from the lcd to your projection lens.
In an ohp the fresnel hat you have is a condesor+field fresnel so placing in a box your fresnel jusr befor re your lcd and your triplet lens will give you the same result that your actual settings.
Note that you can split your ohp fresnel to put your lcd between the condesor and field fresnel.
Note also that some (certainly rare) fresnel from ohp are non splittable 5i foun one on a chip ohp). In this case just use the non splitted setting.
Concerning the condensor:
you should get a benefit from a condensor but you have to find the right one. Short focal, large diameter and tempered glass.
You have to consider that a precondensor lens will increase the size of the minimal spot that you can get after the field fresnel. So you'll loose most of the light improvement.
Right now , I'm not sure that 400w mh and a precondensor lens is a good way to go unless you have a very big projection lens. Everything is linked from the size of your arc bulb to the diameter of your projectyion lens.
I hope this help you!!
you need a condensor fresnel which give homogeneous lighting to your lcd from your (pseudo)ponctual ligh source.
you need a field fresnel which send all the ligh from the lcd to your projection lens.
In an ohp the fresnel hat you have is a condesor+field fresnel so placing in a box your fresnel jusr befor re your lcd and your triplet lens will give you the same result that your actual settings.
Note that you can split your ohp fresnel to put your lcd between the condesor and field fresnel.
Note also that some (certainly rare) fresnel from ohp are non splittable 5i foun one on a chip ohp). In this case just use the non splitted setting.
Concerning the condensor:
you should get a benefit from a condensor but you have to find the right one. Short focal, large diameter and tempered glass.
You have to consider that a precondensor lens will increase the size of the minimal spot that you can get after the field fresnel. So you'll loose most of the light improvement.
Right now , I'm not sure that 400w mh and a precondensor lens is a good way to go unless you have a very big projection lens. Everything is linked from the size of your arc bulb to the diameter of your projectyion lens.
I hope this help you!!
so i should get the same results i am now leaving the 2 fresnals together, and i should not need a condenser lens with the 400w mh and a reflector, right?
yes.
just try like this.
then if you are not happy, you might split the fresnel and add a precondensor lens.
just try like this.
then if you are not happy, you might split the fresnel and add a precondensor lens.
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