page 2.5

Digital Projection LIGHTNING 35HD User Manual 2. Installation
Notes
For more information about
Throw ratio factor (TRF), see
Useful lens calculations, later
in this section.
Choosing a lens
A number of lenses are available for use with the projector. Which lens you choose
will depend on the screen size, image aspect ratio and projection distance.
If you are simply connecting the output of a camera or computer directly to the
projector, then the image size (in pixels) may well be fixed. If, however, you are
using commercially available image processing equipment, such as the Digital
Projection MMS 1000, you may be able to resize the image to fit the DMD.
If the image does not fill the full width of the DMD, this effectively increases the
throw ratio of the lens. This can be corrected for by applying a Throw ratio factor.

Method one: using the lens charts

For the screen sizes listed below, use one of the charts on the following pages, to
choose a lens.
any full width image, including:
native resolution 2048 x 1080 pixels
2.35:1 full width 2048 x 871 pixels
A Throw ratio factor (TRF) has been applied to the following charts:
16:9 full height 1920 x 1080 pixels
4:3 full height 1440 x 1080 pixels
5:4 full height 1350 x 1080 pixels
4:3 unresized 1024 x 768 pixels
5:4 unresized 1280 x 1024 pixels

Method two: by calculation

See the calculations, on the page immediately following the lens charts.