Digital Projection
HIGHlite 660 Series
CHOOSING A LENS
Reference Guide
Ref 19
Rev A November 2012
Choosing a lens by calculation
For any screen size not listed above, or if you need to be more precise, you can use the calculations below.
1. Identify the width of the image in pixels.
2. Calculate the throw ratio factor (TRF):
3. Identify the screen width required.
4. Identify the throw distance required.
5. Calculate the throw ratio required.
6. Choose a lens with the required throw ratio from the list below.
Check from the list that the lens chosen will work at the throw distance required.
Throw ratios for 1080p and WUXGA
Throw distance range
0.77 : 1 fixed lens
1.3 - 2.5 m (4.3 - 8.2 ft)
1.16 : 1 fixed lens
1.4 - 6.2 m (4.6 - 20.3 ft)
1.45 - 1.74 : 1 zoom lens
1.8 - 9.3 m (5.9 - 30.5 ft)
1.74 - 2.17 : 1 zoom lens
2.2 - 11.8 m (7.2 - 38.7 ft)
2.17 - 2.90 : 1 zoom lens
2.7 - 15.4 m (8.9 - 50.5 ft)
2.90 - 4.34 : 1 zoom lens
3.6 - 22.5 m (11.8 - 73.8 ft)
4.34 - 6.76 : 1 zoom lens
5.5 - 35 m (18 - 115 ft)
Notes
The throw ratio for a particular lens
is fixed, but assumes that the image
fills the width of the DMD.
For images that do not fill the width
of the DMD, the throw ratio is
effectively increased. To correct for
this in these calculations, a throw
ratio factor (TRF) is used.
The DMD width is 1920 for WUXGA
and 1080p projectors.
For information about individual lens
part numbers, see
Appendix A
at
the end of this document.
DMD width
Image width in pixels
TRF =
Throw distance
Screen width x TRF
Throw ratio =
