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Author Topic: Light meter Harold Hallikainen Jedi Master Film Handler Posts: 906 From: Denver, CO, USA Registered: Aug 2009 posted 01-30-2014 08:26 PM                        For QC checking, there's always the USL LSS-100. It is permanently mounted in the auditorium. You run a test DCP daily and get reports on luminance, color, and SPL from each speaker. See http://www.uslinc.com/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=58&category_id=18&option=com_virtuemart&Itemid=103&vmcchk=1&Itemid=103 Harold LSS-100 designer  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 01-30-2014 08:31 PM                        I have no idea where one would rent a screen luminance meter, but the device itself is easy to use and does not require training. The tough part is ensuring that the unit is in calibration and in good working order, since these are very sensitive devices and are also somewhat fragile (dropping one would probably an expensive mistake). How much is the LSS-100? It looks like a neat device. Does the screen luminance measurement work with film projectors, too?  |  IP: Logged Phil Ranucci Expert Film Handler Posts: 236 From: Carpinteria,CA, United States Registered: May 2006 posted 01-31-2014 12:30 AM                     I spoke with Photo research about their meters and was told they do rent them, no idea the cost/terms.  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 01-31-2014 07:13 AM                     Renting may be an option for color calibration meters, but for screen luminance checks and lamp adjustments on such a large screen venue, a brightness meter should be on location all the time IMHO. - Carsten  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 01-31-2014 10:10 AM                     I thought they had the aircooled classic machine not a GT I remember one imax booth where they had taken a piece of plywood that covered the port and had solar cells mounted on it where each of the holes in the punched test film were and had a voltmeter beside it so that they could balance the light repeatedly and they had a chart of what the voltage was in relation to a test with a calibrated meter  |  IP: Logged Ivan Plamondon Film Handler Posts: 42 From: Welland, Ontario, Canada Registered: May 2013 posted 02-03-2014 01:20 PM                     Harold, any idea on the cost of a LSS-100?  |  IP: Logged Ivan Plamondon Film Handler Posts: 42 From: Welland, Ontario, Canada Registered: May 2013 posted 02-03-2014 03:14 PM                     Gordon, our IMAX projector is a GT and also uses an air-cooled 7kW superior lamp that is installed horizontally. Casrten, in regards to your comment about affording our own light meter, we as a business have been affected like all others by the recession. Expenses are always a hot button issue. Our last meter broke back in 2004 I believe.  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 02-03-2014 06:35 PM                     Ivan, didn't want to insult you. Just thought that on such a projection system, a light meter should easily pay for itself by being able to utilize these expensive lamps to the max. That said - I just brought home two spot meters from my friend - a Gossen Spot-Master and a SEKONIC L-558. Let's see how they deal with our Ernemann flicker frequency. There is also a Minolta I can tryout later. - Carsten  |  IP: Logged Harold Hallikainen Jedi Master Film Handler Posts: 906 From: Denver, CO, USA Registered: Aug 2009 posted 02-03-2014 07:43 PM                        I'm told the LSS-100 lists for $750US. Dealers may discountbit. Harold  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 02-05-2014 09:28 AM                     Ivan - I checked the two spot meters, but they can't be used for film projection, they do not filter the flicker frequency properly. The Sekonic tries hard and delivers near realtime measurements, but it still jumps up and down. The Spotmaster is completely erratic, as it only does short time measurements and they jump all over the place. They are good for digital projection, but not film. Harold - the LSS-100 is certainly aimed at controlling digital installs - do you know if the luminance meter can cope with film flicker? - Carsten  |  IP: Logged Harold Hallikainen Jedi Master Film Handler Posts: 906 From: Denver, CO, USA Registered: Aug 2009 posted 02-06-2014 07:40 AM                        The LSS-100 integrates over 400ms, so variation due to flicker is minimal (I'll see if I can get some numbers). I've proposed a variation of 1% or less with a flicker frequncy of 48 Hz or higher and duty cycle of 50% or higher to the SMPTE 20F group on luminance measurement. Harold  |  IP: Logged Pete Naples Phenomenal Film Handler Posts: 1565 From: Dunfermline, Scotland Registered: Feb 2001 posted 02-06-2014 04:00 PM                     Carsten/Ivan. I have a Sekonic L558 cine that has been modified to properly integrate projector shutter flicker. I suspect it's running a modified firmware. Certainly put it against my SpecBos 1201 and the readings are close enough not to question the instrument. I don't really use it much these days as I tend to be working on D Cinema so the SpecBos is king. Next time I do have it out I'll see if I can find the details of the mod.  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 02-06-2014 04:49 PM                     That's interesting, Pete. For a second, I even thought I should suggest a modified integration time to Sekonic myself, as the Cine version already outputs cd/qm and fL, and has a dedicated option menu to support special settings like this. But actually I didn't think Sekonic would listen to me, escpecially since film projection will be considered dead now. Please get back to us about this. - Carsten  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 02-06-2014 06:24 PM                     So you have the twin rotor 3d machine?  |  IP: Logged Ivan Plamondon Film Handler Posts: 42 From: Welland, Ontario, Canada Registered: May 2013 posted 02-10-2014 02:13 PM                     No Gordon. Just a 2D projector, single rotor Grand Theatre Unit made in Cambridge, Ontario  |  IP: Logged

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