Lens Selection; Lens Formulas - Barco FLM HD18 User Manual

3. Physical installation
Image 3-15
R9840910: TLD zoom lens (5.0 - 8.0 : 1) ; R9842120:
TLD HB zoom lens (5.0 - 8.0 : 1)
3.2.2

Lens selection

How to select the right lens for your application ?
1. Determine the required screen width (SW).
2. Determine the position of the projector in the projection room with regard to the screen and measure the projector-screen distance
(PD).
3. Use the lens formulas to find the best corresponding PD with regard to the measured projector-screen distance for the required
screen width SW.
Tip: Divide PD by SW to determine the approximate throw ratio. Choose a Lens, which captures the calculated throw ratio.
Use the lens formula of the chosen Lens to recalculate exactly.
Image 3-17
3.2.3

Lens formulas

Formulas
Lens
TLD (0.8 : 1)
TLD HB (0.8 : 1)
TLD (1.2 : 1)
TLD+(1.2:1)
TLD (1.6 – 2.0 : 1)
TLD HB (1.6 – 2.0
: 1)
TLD (2.0 – 2.8 : 1)
TLD HB (2.0 – 2.8
: 1)
TLD (2.8 – 5.0 : 1)
TLD HB (2.8 – 5.0
: 1)
22
Image 3-16
R9829997: TLD+ zoom lens (7.5 - 11.2 : 1)
PD
Throw ratio for Metric formulas (meter)
FLM HD
0.7
PD = (0.71 x SW ) + 0.05
1.1
PD = (1.03 x SW ) - 0.01
1.2 PD= (1.14 x SW) + 0.11
1.35 – 1.70 PD = (1.36 x SW ) - 0.09
min
PD = (1.71 x SW ) - 0.13
max
1.70 – 2.42
PD = (1.71 x SW ) - 0.17
min
PD = (2.42 x SW ) - 0.24
max
2.42 – 4.35 PD = (2.38 x SW ) - 0.16
min
PD = (4.35 x SW ) - 0.38
max
Inch formulas (inch)
PD = (0.71 x SW ) + 1.97
PD = (1.03 x SW ) - 0.39
PD = (1.14 x SW) + 4.33
PD = (1.36 x SW ) - 3.54
min
PD = (1.71 x SW ) - 5.12
max
PD = (1.71 x SW ) - 6.69
min
PD = (2.42 x SW ) - 9.45
max
PD = (2.38 x SW ) - 6.30
min
PD = (4.35 x SW ) - 14.96
max
R5976986 FLM HD18 15/03/2010