my profile | my password | search | faq & rules | forum home

» Film-Tech Forum ARCHIVE   » Operations   » Digital Cinema Forum   » NEC 1200 lamp adjustment

Author Topic: NEC 1200 lamp adjustment Richard May Phenomenal Film Handler Posts: 1057 From: Floral Park, NY USA Registered: Aug 2004 posted 01-30-2013 10:51 AM                     After changing lamps on 5 projectors at one location, I noticed the following. I adjusted the X,Y,Z controls in Z,X,Y order as said in the manual to get the highest readout. I went back and forth a few times to maximize the reading. On every projector the light reading was about 4 to 5 FL higher on the left side of the screen. The top and bottom readings were fine. What gives?  |  IP: Logged Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 01-30-2013 02:42 PM                     don't trust the reading. Unfortunately in my experience it is not reliable. It works perfectly on a Barco or on a Christie - verified with a meter - but it's not reliable on a NEC. NEC itself suggest on their manuals to find the highest reading and then check with a meter. I'd do it by eye: use the controls as you were doing with a 35mm, you'll see some shadows moving on the screen, optimize the position of the lamp so the shadows are not visible. You'll gain a lot of light.  |  IP: Logged Richard May Phenomenal Film Handler Posts: 1057 From: Floral Park, NY USA Registered: Aug 2004 posted 01-30-2013 02:45 PM                     That's what I figured. I did try it by eye quickly, but had trouble shifting the light toward the right side of the screen. I'll try it again.  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 01-30-2013 04:27 PM                     Does anyone know how this metering is actually done across the different brands? Single-sensor, multiple-sensor? Where? - Carsten  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 01-30-2013 09:55 PM                     A uniformity imbalance can be indicative a of a gain screen but more likely, in this case, that the "cold mirror" is not adjusted optimally to center the light from the reflector onto the integrator.  |  IP: Logged Richard May Phenomenal Film Handler Posts: 1057 From: Floral Park, NY USA Registered: Aug 2004 posted 01-30-2013 10:33 PM                     No gain screen here. It's weird that all 7 screens have the same issue. The light meter is working properly. You can see it just by looking at the screen.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 01-31-2013 02:21 AM                     Any silver Screens at your location ?  |  IP: Logged Richard May Phenomenal Film Handler Posts: 1057 From: Floral Park, NY USA Registered: Aug 2004 posted 01-31-2013 10:28 AM                     No silver screens. As I've found with most of the theaters I service that now have digital, the installers were in and out quickly. I've had to readjust things that the installers screwed up. They're the certified ones. What a joke.  |  IP: Logged Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 01-31-2013 12:20 PM                     It's a single sensor after the integrator rod, behind the fold mirror - just after the integrator rod) for a barco. Christie catch the stray light from the vane where the integrator rod is, by the fold mirror. I'm not sure about NEC.  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 01-31-2013 06:36 PM                     Wondering how a single sensor can meet the purpose? Not with a simple maximising approach at least. - Carsten  |  IP: Logged Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 02-01-2013 02:21 AM                     I was skeptical at first, then I did some measurements and Barco and Christie are spot on... Sure, they assume your cold mirror is properly aligned. Particularly Christie approach is stunning: a little box with a light sensor inside that catches the STRAY light in the cavity!! And it works!  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 02-01-2013 06:34 AM                     I can confirm that Barco and Christie's method works very well. NEC can actually mislead (brighter, more even light is attained by not using the built in sensor). Now some NEC's sensors are fine but you can't bank on it.  |  IP: Logged

All times are Central (GMT -6:00)

Printer-friendly view of this topic

Hop To: Select a Forum: Category: Operations -------------------- Digital Cinema Forum Film Handlers' Forum Large Format Forum Ground Level Feature Info, Trailer Attachments & REAL Credit Offsets Category: Community -------------------- Film-Yak Film Handlers' Movie Reviews The Afterlife Bob Maar's Joke-A-Thon Category: Classified -------------------- Equipment and Supplies Wanted/For Sale Help Wanted/Seeking Employment Category: System -------------------- Software Beta Testing Forum

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.