Digital Projection M-Vision 18K Series - Full Lens Calculation Example

page 86
Digital Projection M-Vision Laser 18K Series
Reference Guide
CHOOSING A LENS
Rev D October 2019
Full lens calculation example
Your screen is 4.5 m wide; you wish to place the projector
approximately 10 m from the screen. The source is 4:3.
1. Calculate TRC as follows:
1.6
1.33
TRC =
= 1.2
2. Calculate the throw ratio:
10
4.5 x 1.2
Throw ratio =
= 1.85
3. Find a match in the lens table.
The table shows that the matching lens is the 1.50 - 2.00 : 1
zoom lens.
4. Check whether the lens covers the required throw distance.
The focus range quoted for the 1.50 - 2.00 : 1 zoom lens is
2 - 12 m. The required distance of 10 m is within the range.
Notes
The lens table shown on this page
includes High Brightness lenses
only. For a full list, see Appendix A
at the end of this document.
INFORMATION YOU NEED FOR THESE CALCULATIONS
• The TRC formula
• The TRC table (to use instead of the formula)
2.35:1 (Scope) TRC not used
1.85:1 (Flat) TRC not used
1.78:1 (16:9) TRC not used
1.66:1 (Vista) TRC not used
1.6:1 (16:10) TRC not used (native resolution)
1.33:1 (4:3) TRC = 1.2
1.25:1 (5:4) TRC = 1.28
• The throw ratio formula
• The lens table:
Throw ratios Focus range
1.20 - 1.56 : 1 zoom 1 m - 8 m
1.50 - 2.00 : 1 zoom 2 m - 12 m
2.00 - 4.00 : 1 zoom 2.5 m - 15 m
4.00 - 7.00 : 1 zoom 4 m - 42 m
DMD™ aspect ratio
Source aspect ratio
TRC =
Throw distance
Screen width x TRC
Throw ratio =