Film-Tech Forum ARCHIVE: Turrets and lenses

This is topic Turrets and lenses in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Alan Gilbertson (Member # 242) on 12-04-2003, 12:18 PM:

At one of our location we are going to play some old classic's. So we are taking out the flat lens and changing it to run 1:33. Can someone tell me why the center is moving, when using RP-40 the center line is the same wether you are using 1:85 or 1:33. Can someone please help.

Posted by Scott Norwood (Member # 30) on 12-04-2003, 12:20 PM:

Are these full-frame silent aperture prints, where the picture fills the full width of the film between the sprocket holes (no soundtrack area)?

Posted by John Pytlak (Member # 331) on 12-04-2003, 12:23 PM:

Assume you mean you are running the "classics" with the Academy 1.37:1 aspect ratio. SMPTE 195 specifies a projectable image area of 0.825 x 0.602 inches with the same centerlines as the 1.85:1 aspect ratio. If the vertical centerline is shifting, it may be due to the lens mount.

Or are you running silent films that have NO soundtrack area, and have the centerline down the center of the film?

Posted by Alan Gilbertson (Member # 242) on 12-04-2003, 12:36 PM:

We are playing CASABLANCA, SHANE, SOME LIKE IT HOT, ITS A WONDERFUL LIFE and GONE WITH THE WIND (2:35) none of the prints are silent. And the aspect ratio is 1:37 except for one of them that is 1:66. Our current flat lens (1:85) is 70mm and the 1:37 calculates to a 95mm. As for the lens mount we changed nothing. When you put the flat lens back in everything fall back on center.

Posted by Kris Brunton (Member # 432) on 12-04-2003, 12:51 PM:

What happens when you rotate the 95mm lens in the barrel? What type of turret are you using?

Posted by Alan Gilbertson (Member # 242) on 12-04-2003, 01:08 PM:

The center line stays left of center. We are using a Strong TU-2000 turret.

Posted by John Pytlak (Member # 331) on 12-04-2003, 01:15 PM:

quote:
We are playing CASABLANCA, SHANE, SOME LIKE IT HOT, ITS A WONDERFUL LIFE and GONE WITH THE WIND (2:35) none of the prints are silent.

"Gone With the Wind", "Casablanca", "It's a Wonderful Life", and "Shane" were all composed for Academy (1.375:1) ratio. But "Shane" was shown 1.66:1 since it was released at the beginning of the widescreen era. "Some Like It Hot" was 1.85:1.

http://www.widescreenmuseum.com/widescreen/evolution.htm

quote:
1.66:1
Paramount was the first to break with the traditional 1.37:1 aspect ratio with the release of Shane in 1953. The film, which was photographed conventionally, was projected with the top and bottom cropped to achieve a 1.66:1 aspect ratio and theatres used new larger screens to sell the "new" wide screen concept to the public. Paramount established 1.66:1 for their conventional cropped widescreen presentations.

Do you have the pillar-boxed "scope" version of GWTW, or is it one of the full image 1.37:1 dye transfer prints?

All of these would be shown with a vertical centerline that agrees with the SMPTE 35-PA (RP40) test film, which is 0.738 inches from the reference edge (soundtrack side) of the print.

Posted by Alan Gilbertson (Member # 242) on 12-04-2003, 02:36 PM:

Hi John, we have been told that GONE WITH THE WIND is 2:35 and SHANE is1:66 and the rest of the prints are 1:37

Posted by John Pytlak (Member # 331) on 12-04-2003, 04:00 PM:

"Some Like It Hot" is 1.85:1, not 1.37:1.

All have the same vertical center line.

Today, the "scope" area defined by SMPTE 195 is 0.825 x 0.690 inches, which works out to 2.39:1. Of course, your anamorphic print of GWTW is "pillarboxed" 1.37:1 inside this area.

Posted by John Walsh (Member # 168) on 12-04-2003, 05:19 PM:

What is the make of the lens you are using for 1:33? Also, how far off it it?

Posted by Mark Gulbrandsen (Member # 72) on 12-04-2003, 07:35 PM:

Gone with the wind is definately 1.37. The mid 50's print I owned had its own special aspect ratio as the frames were sometimes a bit shorter than normal, and the I.B. print of Shane I once had ran at 1.37 just fine. Not sure exactly where it should be projected but 1.37 looked correct to me. The DVD of course is there and looks good. Since Shane was filmed in 1953 before the advent of any 35mm Wide Screen process, and Cinerama was just appearing, 1.37 has to be correct. I really don't think 1.66 would look correct for Shane.

Mwahaaaaaaaahaaaaaaaahaaaaaaz TU-2000 [thumbsdown]

Just set up each film with that 95mm lens in the turrett individually using the height stopper and centering adjustments. Takes less than a minuite with RP-40! That turrett's a piece of junk!
Mark @ CLACO

Posted by Steve Kraus (Member # 476) on 12-04-2003, 10:27 PM:

Obviously the turret is not parking the lens so the optical centerline is aligned with the center of the film frame which is throwing the image slightly off but the aim of the projector is compensating. The amount of shift on the screen is going to vary with the focal length of the lens with a greater on-screen shift with a shorter lens. For example a 1mm error might move the picture over by 2 ft with the lens you use for 1.85 but only 18" with the lens you use for 1.37. Thus, when you pop out one lens and put in the other the picture will seem to move by 6" because it's not being shifted in this way as much as with the shorter lens.

You don't notice this normally because the offset is countered by the projector aim and the Scope mount has its own adjustments so that it all works out. As this is a limited event it should not be hard to make whatever adjustments are needed before each film.

Posted by Brad Miller (Member # 2) on 12-05-2003, 02:05 AM:

Steve has definitely pegged it. See if you can get yourself an Align-O-Tron and line up the turret stop with the center line of PA35 test film. This is becoming part of my standard routine now and the increase in sharpness is astounding! It will also fix your problem.