page 83
Digital Projection E-Vision Laser 7500, 8500 & 10K Series
Reference Guide
CHOOSING A LENS
Rev D August 2017
Basic calculation example
1. Calculate the throw ratio using the formula.
Your screen is
4.5 m
wide and you wish to place the projector
approximately
11 m
from the screen. The throw ratio will then be
11
4.5
=
2.44
2. Match the result with the lens table.
The lens matching a throw ratio of 2.44 is
the 2.22 - 3.67 : 1
zoom lens
.
3. Check whether the lens covers the required throw distance.
The focus range quoted for the 2.22 - 3.67 : 1 zoom lens is
2.36
- 24.2 m
. The required distance of 11 m is within the range.
Notes
The basic calculation on this page
does not take into consideration
DMD™ and image size, which could
affect the throw ratio. For a more
complex and realistic calculation,
in this
section.
For information about individual lens
the end of this document.
INFORMATION YOU NEED FOR THIS CALCULATION
•
The throw ratio formula:
Throw distance
Screen width
Throw ratio =
•
The lens table:
Throw ratios
Focus range
0.82 m - 2.71 m
1.02 m - 12.7 m
0.81 m - 5.08 m
1.33 m - 11.73 m
1.83 m - 14.9 m
2.36 m - 24.2 m
3.8 m - 35.35 m
0.38 : 1 fixed (UST)
0.75 - 0.93 : 1 zoom
0.76 : 1 fixed
1.25 - 1.79 : 1 zoom
1.7
3
- 2.27 : 1 zoom
2.22 - 3.67 : 1 zoom
3.58 - 5.38 : 1 zoom
5.31 - 8.26 : 1 zoom
5.59 m - 54.8 m
