Need a few good eyes to double check my math, also found a discrepancy I can't explain.
Using a jvc dla-rs48 projector and a 130 inch wide 2.35 screen (55.3 high) with 26 inches of drop and the case is 6 in. This should also yield a 55.3 high by 98.3 wide 16x9 image. All of this via zooming for now (no lense or sled).
Throw distance:
The projectors site say the lense is 1.4:1 to 2.8:1 so:
At 2.35 of 130 wide x 1.4 = 182" or 15'2" minimum
At 16x9 of 97 wide x 2.8 = 271" or 22'7" maximum
So my plan is to put the projector lens 15'5" back
Here is one thing I can't reconcile is that jvc's own website calculations show at 16x9 the min at 11.15 and max at 22.7 kind close. But when I change it to 2.35 it kicks out, on a 130w 55.3h a minimum distance of 14.78 and max of 30.8. Shouldn't my numbers and theirs match up exactly?
Vertical shift:
The projector features a 80% v shift, which in jvc's case really means 30% of the screen height. So rounding the height to 55" you get:
55" x 0.30 = a little more than 16 inches of shift (I'm trying to stay away from using any edges of limits).
So the screen case is 6 in mounted and 26 in of drop make the top of the screen 32" from the ceiling.
32" - 16" shift = 16" projector height.
Is this from center lens, top of lens or bottom?
So if I use a 18 in downtube I should be ok...?
Thank you in advance
Using a jvc dla-rs48 projector and a 130 inch wide 2.35 screen (55.3 high) with 26 inches of drop and the case is 6 in. This should also yield a 55.3 high by 98.3 wide 16x9 image. All of this via zooming for now (no lense or sled).
Throw distance:
The projectors site say the lense is 1.4:1 to 2.8:1 so:
At 2.35 of 130 wide x 1.4 = 182" or 15'2" minimum
At 16x9 of 97 wide x 2.8 = 271" or 22'7" maximum
So my plan is to put the projector lens 15'5" back
Here is one thing I can't reconcile is that jvc's own website calculations show at 16x9 the min at 11.15 and max at 22.7 kind close. But when I change it to 2.35 it kicks out, on a 130w 55.3h a minimum distance of 14.78 and max of 30.8. Shouldn't my numbers and theirs match up exactly?
Vertical shift:
The projector features a 80% v shift, which in jvc's case really means 30% of the screen height. So rounding the height to 55" you get:
55" x 0.30 = a little more than 16 inches of shift (I'm trying to stay away from using any edges of limits).
So the screen case is 6 in mounted and 26 in of drop make the top of the screen 32" from the ceiling.
32" - 16" shift = 16" projector height.
Is this from center lens, top of lens or bottom?
So if I use a 18 in downtube I should be ok...?
Thank you in advance
