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Author Topic: IMAX lenses changing during trailers? Thomas Pitt Master Film Handler Posts: 266 From: Leeds, West Yorkshire, UK Registered: May 2007 posted 03-29-2018 02:22 PM                     I went to see my first ever movie in multiplex IMAX (I call it IMAX Lite), and noticed something during the adverts and trailers. From what I could see, it looked like the projector lenses or something inside the projector was moving about during the black segments between trailers. As I don't know much about this kind of projection system except that it uses two projectors, I'm wondering if this is normal. If so, why does it happen? Do different trailers use different lenses?  |  IP: Logged Ken Lackner Phenomenal Film Handler Posts: 1907 From: Atlanta, GA, USA Registered: Sep 2001 posted 03-29-2018 03:08 PM                     You might be seeing the dousers or 3D polarizers move. An IMAX system does not use the projector's stock douser. There is a douser mounted outside the projector in front of the lens that moves side-to-side to block or allow the light from the lens to hit the screen. The polarizers are mounted to the same device. I am pretty sure they are only activated when 3D content is playing, but I couldn't swear to it.  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 03-29-2018 03:38 PM                     The laser systems also use automated anamorphic lenses, so there is quite some potential to see things move in and out. - Carsten  |  IP: Logged Paul Arch Film Handler Posts: 5 From: Ipswich, Suffolk, United Kingdom Registered: Apr 2018 posted 04-03-2018 02:57 PM                     My local Digital IMAX does this during film trailers. I wasn’t sure whether it was the system switching between single and dual projection. As I have noticed that during some trailers (for IMAX features) that don’t have ‘in IMAX’ at the end there seems to be only one projector on and for others both are on. My other theory was it was switching between ratios and showing trailers in scope or flat, which ever is the true format of the film as IMAX is common width, they could possibly do this?  |  IP: Logged Jarod Reddig Jedi Master Film Handler Posts: 513 From: Hays, Ks Registered: Jun 2011 posted 04-03-2018 06:13 PM                     As said I think your seeing the 3D dousers moving. Ive noticed it before too. Ive never been able to look into the booth when it happened tho.  |  IP: Logged

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