Re: Can an anamorphic movie still looked vertically stretched when projected with an anamorphic lens?

lchiu7@xxxxxxxxx wrote:

>This is a new multiplex so I would assume that they had the chance to
>build the booths in the right place.

Depends on who built it and who outfitted the booth. There have been
a lot of theatres gone belly up, and a lot of lenses and equipment
recycled. Forty year old projectors that have been rebuilt are
common, and work just fine.

>I hadn't considered keystoning -
>that might be an answer. At least I feel somewhat more relaxed that the
>problem I saw isn't just my imagination!
>
>The alignment of the image on the screen is also a potential factor.
>The actual movie screen appears to have a 16:9 AR. So when they show a
>scope picture the curtains come down to matte the screen to a scope AR.
>Now if the projector were aligned to project a perfect 16:9 image, and
>then a scope film showed, you would expect to avoid any keystoning, the
>matte to be achieved by cropping an equal amount from the bottom and
>top of the screen. In fact I am pretty sure it's achieved by only
>matting the top. This might mean that the projector lens has to be
>aimed slightly down which could cause the slight elongation.

Not really. The top masking goes down, the lens and plates get
changed, but the projector angle and lens angle are never changed.
Lenses are mounted so that they only fit in the barrel one way. There
are offsets that are used in extreme situations, but that wouldn't
happen in a new multiplex. The aperture hole in the plate only gets
filed after the projector has been installed, screen and masking
mounted, and lens chosen. The hole is rarely a perfect rectangle, but
is designed to keep the picture from bleeding more than a couple of
inches into the surrounding masking. Depending on the lens and angle,
the hole can be a trapezoid, barrel shaped, or narrower in the center
than at the corners. In this case the hole is probably centered a
little higher and the picture cropped a little to allow the transition
from flat to scope without having to rack the framing on the
projector.

>For a theater with a full 2:35.1 screen that mattes on the side when
>showing 16:9 movies, I guess you would not see this problem? Just
>speculation on my part anyway

Side masking is preferred, yes. I've never seen side masking that
didn't adjust on both sides, and that does resolve a lot of potential
problems.

The way that you or the projectionist or installer would discover what
is going on is run a test loop of film that shows the correct aspect
ratios.
.

Relevant Pages

  • Re: Do achromats shift an image?
    ... them apart to get the entire image within the confines of the lens. ... from the line of the projector lens. ... It sounds like your projector has offset. ... If you tilt the optical axis of these lenses off of the ...
    (sci.optics)
  • Re: Another Question - Projectors
    ... Some projectors have options on the lens you can buy. ... short throw wide angle lens available as well as a wide angle zoom ... lens that replaces the standard lens. ... could put the projector back another 5' if I had to. ...
    (alt.tv.tech.hdtv)
  • Re: Projection Optics
    ... The light from the projector lens would enter the ... 2)It needs generous eye relief so the exit pupil of the telescope (which is ... As for the mirror, I think just a simple piece of thin, uncoated glass would ...
    (sci.optics)
  • ripping and reusing the sensor out of a digital cheapie
    ... to create a telecine machine for transferring Super8 film to a digital ... the sensor being located as close to the film projector gate as ... possible with the minimum of lens inbetween? ...
    (uk.rec.photo.misc)
  • Re: tv license question (a new one!!)
    ... OK, so instead of drilling a big hole in the wall, the projector is ... neighbour's house, with the projected image exiting from the far end ...
    (uk.legal)