 | | | Camera FOV vs Focal Length | Camera FOV vs Focal Length 2005-05-09 - By Marc Bourbonnais
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The relation between FoV, lens and aperture is correct in XSI. It's the same
trig relation between the 3 values.
The problem is the incorrect default aperture sizes for the HD cams, so I can
assume you are working with these types of plates.
The correct aperure size for high-end HD cams is 9.6mm x 5.4mm, roughly 0.37795
" x 0.2126". Not the default XSI values.
The magic trig relation is :
f = (0.5*Ap) / tan(0.5*FoV)
where
f = lens
Ap = aperture
FoV = Field of view angle
of course keep track of mm vs. inches, and horizontal vs. vertical.
--
Marc Bourbonnais
3D TD
Hybride
(450)227-4245
-- -- Original Message -- --
From: Andre DeAngelis
To: XSI@(protected)
Sent: Monday, May 09, 2005 10:58 AM
Subject: Camera FOV vs Focal Length
Hello All,
Can anyone point me in the direction of a reference that explains the formula
for the relation between FOV, Focal Length and Film Aperture used by XSI's
camera?
The presets in XSI's camera don't seem to correlate to what the table the
director has given us and I want to put a script/plug-in to reproduce the table
he has provided.
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<BODY lang=FR-CA vLink=purple link=blue bgColor=#ffffff>
<DIV><FONT face=Arial size=2>The relation between FoV, lens and aperture is
correct in XSI. It's the same trig relation between the 3 values.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The problem is the incorrect default aperture
sizes
for the HD cams, so I can assume you are working with these types of
plates.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The correct aperure size for high-end HD cams is
9.6mm x 5.4mm, roughly 0.37795" x 0.2126". Not the default XSI
values.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The magic trig relation is :</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>f = (0.5*Ap) / tan(0.5*FoV)</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>where </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>f = lens</FONT></DIV>
<DIV><FONT face=Arial size=2>Ap = aperture</FONT></DIV>
<DIV><FONT face=Arial size=2>FoV = Field of view angle</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>of course keep track of mm vs. inches, and
horizontal vs. vertical.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV>--<BR>Marc Bourbonnais<BR>3D TD<BR>Hybride<BR>(450)227-4245</DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT:
#000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">-- -- Original Message -- -- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=andre.deangelis@(protected)
href="mailto:andre.deangelis@(protected)">Andre DeAngelis</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=XSI@(protected)
href="mailto:XSI@(protected)">XSI@(protected)</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, May 09, 2005 10:58 AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Camera FOV vs Focal Length</DIV>
<DIV><BR></DIV>
<DIV class=Section1>
<P class=MsoNormal><FONT face=Arial size=2><SPAN lang=EN-CA
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Hello
All,<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN lang=EN-CA
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT><
/P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN lang=EN-CA
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Can anyone point me in the
direction of a reference that explains the formula for the relation between
FOV, Focal Length and Film Aperture used by XSIs
camera?<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN lang=EN-CA
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT><
/P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN lang=EN-CA
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">The presets in XSIs camera dont
seem to correlate to what the table the director has given us and I want to
put a script/plug-in to reproduce the table he has
provided.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN lang=EN-CA
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT><
/P>
<P class=MsoNormal><FONT face=Arial size=2><SPAN lang=EN-CA
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">AD<o:p></o:p></SPAN></FONT></P><
/DIV></BLOCKQUOTE></BODY></HTML>
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