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Author Topic: Barco light sensor Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 05-02-2015 04:14 AM                     Sure Steve, that's what I do. But what if you turn up servicing the projector and the lamp is due to be replaced and all you get on screen is 12fL? Can you tell the Christie to aim for a higher LiteLOC number for when the lamp is replaced or upgraded? I installed a Barco with a 3kW lamp, light level was about 56fL. The customer purchased that machine in case they wanted 3D. The machine arrived with a 3kW lamp from Barco. I told the customer to install 2kW lamps instead. I did the colours, defocussed the lamp a little to have a more reasonable light output and then set the CLO to 14fL. The projector was running the 3kW lamp at min power. When the 3kW lamp was replaced with a 2kW one, CLO simply adjusted to 14fL. Sure, they may have not been precisely 14fL but close enough. Had it been a Christie... I couldn't have done that. I would have probably disabled the LiteLOC altogether. Agree on everything else!  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 05-02-2015 11:37 AM                     Not so...defocus the lamp/lower the power until you get your light meter to read 14fL...then set the Lightloc there. If you want you can let it go back up to the original reading on the over-sized lamp...LightLoc will try to turn the lamp down within its range and, like the Barco, never get there...when the new smaller lamp is installed, it will still try to hit the target number you set up originally...just like the Barco. In truth, what Barco has is the ability to assign a meaningful number (Foot Lambert) to the internal number. Christie has a pathetic calibration procedure that can only be meaningful for one format (I tend to use FLAT as my calibration point). However, since they use Max/Min as their set points, they presume a linear scale, I guess because 14fL is never 14fL...I've occasionally tried to get it to read right but just didn't find the time worth it. There is nothing to stop you from creating LightLoc files for 12fL, 13fL ...etc of each format too...you just need to do it with a calibrated meter to find what the LightLoc number is.  |  IP: Logged Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 05-02-2015 11:42 AM                     Steve, That is correct - even though cumbersome. But the most common scenario is the other one: servicing a machine with an old lamp which does not reach 14fL anymore.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 05-02-2015 01:25 PM                     Okay...so how is that different than on a Barco? If the lamp doesn't reach the target level it doesn't reach it. The only difference is that you can specify your desired level in fL.  |  IP: Logged Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 05-02-2015 05:47 PM                     That's exactly my point. I described two scenarios: 1) the lamp is due to be changed - or overdue - and light levels in the room are only, say, 12fL. On a Christie you cannot tell LiteLOC to aim for 14fL. On a Barco you can. 2)The lamp cannot reach 14fL and you advise the customer to upgrade to a bigger one. You don't want to go back just to set light levels, do you? Just dial 14fL on CLO and when the new lamp is fitted it will be driven to the proper level with reasonable accuracy.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 05-03-2015 11:43 AM                     But you did calibrate the Christie sensor to some light level, right? So lets say you set Flat to 12fL and set LightLoc your example. You can then increase the power until it reads 14. Then increase the power until it reads 2fL more then call that setting 14fL. Likewise for Scope...if it normally reads something like 19fL with the old lamp...increase until it reads 21fL and make a new setting. It isn't rocket science and in neither case are the light sensors as accurate as recalibrating with a proper light meter but sufficient for your customer to keep the light good and in the safe operating range.  |  IP: Logged Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 05-04-2015 03:02 PM                     Maybe I'm on the wrong end of the stick here. What if your lamp is producing 12fL at max power because it's an old lamp?  |  IP: Logged Jay Glaus Expert Film Handler Posts: 123 From: Pittsburgh, PA USA Registered: Dec 2010 posted 05-05-2015 12:05 AM                        Just an update… Aligned the lamp on the screen using a light meter, and the number was pretty much rock solid. So, that has pretty much told me the bulb does not have much wander or flicker, but I figured it didn't. I've been told to unplug and plug back in the CLO sensor, and see if that changes anything, if not, I may end up changing it. The 32B is 3 years old and we haven't run anything smaller than a 6.5k bulb in her, I've heard the sensors can cook over time.  |  IP: Logged Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 05-05-2015 11:41 AM                     the light sensor is BEHIND the fold mirror, it receives the 'leftover' from it. I don't think it can overheat.  |  IP: Logged

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