Digital Projection
Titan Quad & Titan 800 Series
CHOOSING A LENS
Reference Guide
Ref 22
Rev B 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 ratios for SX+
Lens extension (±2%)
Throw distance range
0.67 : 1 fixed lens
0.73 : 1 fixed lens
204 mm (8.0 in)
1.1 - 3.2m (3.6 - 10.5ft)
1.12 : 1 fixed lens (3 - 15m)
1.21 : 1 (3 - 15m) fixed lens
268 mm (10.6 in)
3 - 15m (9.8 - 49.2ft)
1.12 : 1 fixed lens (1.2 - 2m)
1.21 : 1 (1.2 - 2.0m) fixed lens
268 mm (10.6 in)
1.2 - 2m (3.9 - 6.6ft)
1.16 - 1.49 : 1 zoom lens
1.26 - 1.61 : 1 zoom lens
226 mm (8.9 in)
3 - 15m (9.8 - 49.2ft)
1.39 - 1.87 : 1 zoom lens
1.5 - 2.02 : 1 zoom lens
194 mm (7.6 in)
4 - 24m (13.1 - 78.7ft)
1.87 - 2.56 : 1 zoom lens
2.02 - 2.77 : 1 zoom lens
159 mm (6.3 in)
4 - 24m (13.1 - 78.7ft)
2.56 - 4.17 : 1 zoom lens
2.77 - 4.51 : 1 zoom lens
145 mm (5.7 in)
9.1 - 45m (29.9 - 147.6ft)
4.17 - 6.95 : 1 zoom lens
4.51 - 7.53 : 1 zoom lens
129 mm (5.1 in)
12 - 80m (39.4 - 262.5ft)
6.93 - 10.34 : 1 zoom lens
7.5 - 11.2 : 1 zoom lens
179 mm (7.0 in)
12 - 80m (39.4 - 262.5ft)
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, and 1400 for
SX+ projectors.
Throw distance calculations are
based on the distance from the outer
end of the lens, which will vary from
lens to lens. Once a lens has been
chosen, the figures can be checked
using the lens extension values
given in the table on this page.
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 =
