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Author Topic: Lens turrets on 35/70 machines Andrew McCrea Jedi Master Film Handler Posts: 645 From: Winnipeg, Manitoba, Canada Registered: Nov 2000 posted 08-25-2006 11:49 AM                        Hey everyone, I've seen 35/70 projectors with lens turrets (Flat/Scope), but I've noticed in literature it says that the turrets are for 35mm lenses only. Is this because the 70mm lenses are too big and heavy to be rotated in a turret? If you have a 35/70 machine with a turret, where/how do you put the 70mm lens in? Do you just switch out on of the other lens (scope/flat) or something, or could you just get a three lens turret and use the empty third one?  |  IP: Logged Aaron Sisemore Flaming Ribs beat Reeses Peanut Butter Cups any day! Posts: 3061 From: Rockwall TX USA Registered: Sep 1999 posted 08-25-2006 12:09 PM                     Many of the older 70mm lenses were 4" diameter and therefore wouldn't fit in a turret to begin with. The newer 70mm lenses are the same physical size as a 35mm lens- I don't see why they wouldn't work, (weight-wise they would weigh less than a full-size anamorphic) unless the turret doesn't have the facility to alter the optical center between the two formats. -Aaron  |  IP: Logged Andrew McCrea Jedi Master Film Handler Posts: 645 From: Winnipeg, Manitoba, Canada Registered: Nov 2000 posted 08-25-2006 12:46 PM                        One more question then; bear with me as I don't completely understand the optics behind lenses, but what is the optical centre and what would the alteration be?  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 08-25-2006 01:12 PM                        The image on a 35mm sound print is off-center with respect to the film because the soundtrack occupies one edge of the film. The projector lens mount is normally located at the center of the image area and the lens normally needs to be re-centered for 35mm silent prints, 35mm mag-only prints, and 70mm prints, where the image center is centered with respect to the film. Usually, the lamp alignment needs to be tweaked as well, and 70mm requries a beam spreader lens. The only 35/70 machines with turrets that I have seen are the JJs at Brad's screening room and he can run 70mm just fine.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 08-25-2006 03:59 PM                     Scott, I have since switched the left projector back to a single lens head. Dealing with the gate design on a turret is a major bitch, as the only good way to set the clearance and tension is with film running and the gate isn't spring loaded at that point, it is latching.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 08-25-2006 04:38 PM                     The Victoria 8 had a 4" diameter lens turret and the wetrex 5000 had a 3 lens turret marked flat scope and 70mm  |  IP: Logged

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