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Author Topic: Achieving uniform focus Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 05-12-2004 06:24 PM                     My biggest beef with the Schneider PC adapter, other than the cost is the poor method of clamping the lens. I have had scope lenses drift ever so slowly out if they are stored on end. Steve  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 05-12-2004 09:41 PM                     Steve, I assume you mean the black PC corrector...... My beef is that when the clamping screws are loosened a scope lens, ok any lens, will sag downward making alignment a very trying thing to achieve. The little adjustment eccentric is also a waste of time and money as any very fine setting with it is impossible to acheive.... one touch and the pictures in an entirely different placec!! Mark  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 05-12-2004 09:41 PM                     Steve, I assume you mean the black PC corrector...... My beef is that when the clamping screws are loosened a scope lens, ok any lens, will sag downward making alignment a very trying thing to achieve. The little adjustment eccentric is also a waste of time and money as any very fine setting with it is impossible to acheive.... one touch and the pictures in an entirely different place!! Mark  |  IP: Logged Ken Lackner Phenomenal Film Handler Posts: 1907 From: Atlanta, GA, USA Registered: Sep 2001 posted 05-12-2004 11:46 PM                     I wasn't really looking for specific answers, it was just a general question. We have Simplex 1060 projectors in some houses, and Century SA's in others. The lenses are Schneider. The screen size, throw, and angle will be different for each house, and I don't know that information. [ 05-14-2004, 01:16 AM: Message edited by: Ken Lackner ]  |  IP: Logged Michael Schaffer "Where is the Boardwalk Hotel?" Posts: 4143 From: Boston, MA Registered: Apr 2002 posted 05-13-2004 12:27 AM                        quote: Ken Lackner We have Sinplex 1060 projectors That sounds like equipment for a multi-screen porn house! The theatres Frank describes sound like they probably had very steep stadium seating. If you are sitting above the screen looking down, that is OK I think, but not if you are sitting lower than the screen looking up.  |  IP: Logged William Hooper Phenomenal Film Handler Posts: 1879 From: Mobile, AL USA Registered: Jun 99 posted 05-13-2004 03:58 AM                        quote: Michael Schaffer The theatres Frank describes sound like they probably had very steep stadium seating. If you are sitting above the screen looking down, that is OK I think, but not if you are sitting lower than the screen looking up. They're old legit theaters ca. turn of the 20th century that had projection equipment added. Most vaudeville houses (for example, Lansburgh's Orpheums) pretty much were of similar plan. I can't find a decent section of one online, & seating charts are usually distorted in scale. There's a sliver of the New Amsterdam visible in a picture at its site here . Typically they're spoken of as following "European opera house" design, but their design evolution in the US was pretty specific. The best description I heard was from Rene Brunet who called the type "a vertical theatre" or "vertical hall" (now I hear & see it in use in a lot of places. Originally built for stage productions, the seating on the floor was not as deep (still spacious, though), & they had 2 or more balconies (loges, mezzanines, people will call them what they want even though loges & mezzanines have other, specific meanings). The balconies were fairly steep, but it worked out as very good for proximity to the stage & sightlines, resulting in very good, intimate seating even as you got up to the top balcony. Overall they were more square or undersquare than what the theater & movie palace plans evolved to. By the end of the silent era, big movie theaters with balconies tended to be longer with a sea of seats on the floor in front of the balcony, & with a less steep balcony. Smaller theaters were appreciably longer than wide, too. The reason can be guessed from previous discussion here: for film, less keystone & more straight-on view of the screen in the balcony. (European design, which was actually based on English & European design & was what US theaters followed in the 18th & 19th centuries, was not as vertical or intimate. The construction was a buncha seats on the floor, that whole area of floor seating called the pit, then a row of boxes running around the back & side walls, & then usually galleries above the boxes. The galleries & boxes at the back did not come so close & were not as intimate with the stage, as the large 'pit' a.k.a. floor seating was mostly in between. In the US, the 'vertical' design evolved as pulling balconies more & more over the 'pit' or floor seats, cranking the balcony angle, stacking 'em up.) Going from something like the New Amsterdam or aone of Lansburgh's Orpheums (pre-film vertical theaters built for live productions, legit or vaudeville), to the Chicago (1921, built for film, not quite as vertical, but still wider than long) to houses at the end of the silent/movie palace era (spectacular things like the Los Angeles, UA, or spectacular late-20s Loew's & Paramount theaters), they stretched out & squashed flatter. The longer they get, though, the less enjoyable they are for live shows, until you get to some which have the show a block away from the back rows. There's an excellent middle period particularly of Thomas Lamb's ca. 1926 theaters that are smack in the middle & to drool over for live or film use. These were things like those of Thomas Lamb's with the later Adamesque interiors (all very handsome & formal) before his sudden design freakout of spectacular things like the Loew's Jersey, 72nd Street, Louisville, etc. which by then were deeper & shorter. So the older, wider-than-long theaters did resemble stadim theaters in plan as you noted, but not in section. The projection booth was put wherever, usually winding up in the top balcony. Some built-before-movies theaters had projection booths which moved several times from the 1st balcony, to second, to top during their film days). Hey Frank, if they haven't completely sealed the Liberty for renovation yet, see if you can absentmindely wander in like you're lost & get a picture of that lovely projection booth it had last installed. Asbestos panels, hung from the ceiling.  |  IP: Logged Ian Bailey Master Film Handler Posts: 317 From: Nambucca Heads, Australia Registered: Jun 2003 posted 05-13-2004 08:25 PM                     Adam I just can't understand how a mis-aligned lamphouse can affect focus.I would assume it would effect the amount of light on the screen but can it cause a focus problem like I have now in my small auditorium where the picture is out of focus in the right-hand bottom corner compared to the rest of the screen?  |  IP: Logged Ken Lackner Phenomenal Film Handler Posts: 1907 From: Atlanta, GA, USA Registered: Sep 2001 posted 05-14-2004 01:15 AM                     quote: That sounds like equipment for a multi-screen porn house! My bad. Post edited to correct typo.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 05-14-2004 09:37 AM                     Ian said "Adam I just can't understand how a mis-aligned lamphouse can affect focus.I would assume it would effect the amount of light on the screen but can it cause a focus problem like I have now in my small auditorium where the picture is out of focus in the right-hand bottom corner compared to the rest of the screen" The optical train of the projector is two have much like the way the sound system has an A and a B chain The lightsource and its optics project a convergin beam of light at the apperture that converges at a distance in front of the apperture and i a pin hole was placed in the lensmount you could focus a image at a distance dependent on the reflector alone The projector lens also has a point of convergance depending on its focal length and the axis of these two systems must be in line for either to work properly. Certain lens / reflector combinations are more sensitive than others  |  IP: Logged Ian Bailey Master Film Handler Posts: 317 From: Nambucca Heads, Australia Registered: Jun 2003 posted 05-14-2004 07:39 PM                     Thanks for the information Gordon.  |  IP: Logged

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