Digital Projection
Titan Quad & Titan 800 Series
CHOOSING A LENS
Reference Guide
Ref 23
Rev B November 2012
Throw distance and lens extension
The throw distance is calculated to the outer end of the lens. The nominal
distance between the front of the projector and the outer end of the lens is
called
lens extension
.
Lens extension values will vary from lens to lens. Once a lens has been
chosen, the figures can be checked using the values given on the previous
page.
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.
For information about lens
extensions and individual lens part
numbers, see
Appendix A
at the
end of this document.
Lens extension is measured when
the lens is focused at infinity, and
fully extended. At other focus
settings, the extension could be up
to 10mm less.
Lens extension measured from front of corner post
