I didn't say it was constant, I gave the size for shooting 4k. The lens focal length is constant as long as the mount is to spec for the given mount. and by constant I mean the focal length of a lens doen't change with the amount of image plane being used. So a 25mm is a 25mm (sort of) regardless of the resolution you are using on the red. The only thing that changes is perceived angle of view. The focal length is the distance of the real nodal to the film plan always. This changes with focal distance as when you focus the rear nodal point moves to adjust convergence on the focal plane (not to be confused with focus plane) Randy S. Little http://www.rslittle.com
On Tue, Oct 11, 2011 at 01:14, Ron Ganbar <[email protected]> wrote: > Thanks guys for all your help. > But I think I'm confused now. There's conflicting answers in here I believe. > Randy says the lens is as is with a constant film back size (22.2mm x > 12.6mm), while Misho says I should use 0.96 conversion for the lens. > Basically it's a Red One shooting 3K with an 18mm lens. > > Thanks again all. > > Ron Ganbar > email: [email protected] > tel: +44 (0)7968 007 309 [UK] > +972 (0)54 255 9765 [Israel] > url: http://ronganbar.wordpress.com/ > > > On 10 October 2011 21:00, Simon Björk <[email protected]> wrote: >> >> The Red can capture footage in a variety of ways, 4K 16:9, 2K 16:9 etc, >> and they all crop the sensor in different ways. To find out what sensor size >> you should use, just multiply the pixels of your image by 0.0054 (the size >> of the pixels on the sensor in mm). >> For example, if the camera captured footage in 4K 16:9 (4096x2304) you >> could calculate the sensor size like this: >> 4096*0.0054 = 22.11mm >> 2304*0.0054 = 12.44 mm >> /Simon >> 2011/10/10 Misho Ristov <[email protected]> >>> >>> Red One 0.96 in >>> Red Epic 1.0885 in >>> >>> - >>> Misho >>> >>> >>> On 2011.10.10 8:27 PM, Ron Ganbar wrote: >>> >>> Hi all, >>> needing to cam track some Red footage. Anybody knows what the film back >>> is, and if I should change the focal length to compensate for a different >>> size film back? >>> >>> Thanks, >>> Ron Ganbar >>> email: [email protected] >>> tel: +44 (0)7968 007 309 [UK] >>> +972 (0)54 255 9765 [Israel] >>> url: http://ronganbar.wordpress.com/ >>> >>> >>> _______________________________________________ >>> Nuke-users mailing list >>> [email protected], http://forums.thefoundry.co.uk/ >>> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >>> >>> -- >>> ___________________________ >>> Misho Ristov >>> VFX Supervisor >>> FX3X >>> www.fx3x.com >>> Jane Sandanski 108/28 >>> 1000 Skopje, Macedonia >>> cell +38970385680 >>> office +38925511985 >>> fax +38925511902 >>> >>> _______________________________________________ >>> Nuke-users mailing list >>> [email protected], http://forums.thefoundry.co.uk/ >>> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> >> >> >> >> >> _______________________________________________ >> Nuke-users mailing list >> [email protected], http://forums.thefoundry.co.uk/ >> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users > > > _______________________________________________ > Nuke-users mailing list > [email protected], http://forums.thefoundry.co.uk/ > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users > _______________________________________________ Nuke-users mailing list [email protected], http://forums.thefoundry.co.uk/ http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users
