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Author Topic: Xenon lamp alignment Matthew Taylor Expert Film Handler Posts: 186 From: Essex, UK Registered: Mar 2004 posted 04-02-2005 07:23 AM                     I'm hoping you can help me. I have got my small Cinemaccannica CX-450 working reasonably well with my Prevost P70. I'm certain I could squeeze some more light out of it with better alignment though. The facts are this; I don't have an 'alignotron'. I don't know the optimum distance between the lamp and the gate. To the best I can without the correct tools, how can I; a) align the lamphouse in relation to the projector both vertically and horizontally (the lamphouse is sitting on bits of wood at the moment) b) best focus/align the mirror once the lamphouse is in the correct position. I have looked at the archives and seen the 'string method' mentioned but found no reference to what it actually is.  |  IP: Logged Darryl Spicer Film God Posts: 3250 From: Lexington, KY, USA Registered: Dec 2000 posted 04-02-2005 12:37 PM                    I guess you could try to project the light to the screen with out the lens and make sure that the dark spot is as centered to the screen as possable then try and focus the light with the scope lens in placefor the brightest picture with just a bit of darkness in each corner of the screen. Making sure the light is evenly spread.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 04-02-2005 12:44 PM                     Cut out two disks that are the diameter of the ens mount and puch a pin hole in the dead centre (for this to work they have to be accurate) remove the lamp and in the cntre of the mirror is round tube look through the two pinhole to align the lamphouse so that the centre of tat tube is in line ith the pin holes then install the lamp and make sure it is visible on the same axis that will get you in the ballpark The original method for these was with steel rod and dummy lens  |  IP: Logged Jacek Dejnarowicz Film Handler Posts: 12 From: Mrzezyno, Zach, Poland Registered: Mar 2005 posted 04-03-2005 05:01 AM                     The optimum distance between the lamp and the gate depends on your mirror and lens. The lamp need to be at the first and the gate at the second focus of the mirror. And finally the size of focused light beam must be equal aperture of the lens. I don't know if it's clear cause of my weak english. I think the best way is to find specification of your lamphouse.  |  IP: Logged Darren Briggs Master Film Handler Posts: 371 From: York, UK Registered: Dec 2001 posted 04-03-2005 08:03 AM                        You can also focus the lamp on a wall by pointing the lamphouse at a wall, to ensure you have the mirror and xenon perfectly aligned. then mount the lamphouse on the projector ensuring that the image of the xenon is bang in the middle of the screen, or using the method using string works well.  |  IP: Logged Greg Mueller Phenomenal Film Handler Posts: 1687 From: Port Gamble, WA Registered: Jun 99 posted 04-03-2005 10:49 AM                        Matt If you send me a picture of your set up, maybe I can help you figure it out.  |  IP: Logged Matthew Taylor Expert Film Handler Posts: 186 From: Essex, UK Registered: Mar 2004 posted 04-03-2005 05:08 PM                     Thanks Greg, I will do. It may take a couple of days because I have to borrow my brother's digicam.  |  IP: Logged Gilbert Travin Expert Film Handler Posts: 101 From: Villeurbanne / France Registered: Jan 2004 posted 04-04-2005 07:03 AM                        Matthew ; You can use a laser pointer ... to align film gate and lamphouse. then you can align projector axis with screen axis. But the "great" problem with Prevost is to adjust correctly the turret because there are too many adjustments of the turret (I believe 3 adj. : lock position, 35/70 translation and each lens ...) : this operation will be long. If your mirror is designed for 16 mm operation, you will have "dark" zones on the two sides of the screen, especially in 70 mm . Good luck !  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 04-04-2005 09:25 AM                     The CX450 and CX900 are basically a 16mm design and a beam diffuser is required in the snood to expand it to 35mm  |  IP: Logged System Notices Forum Watchdog / Soup Nazi Posts: 215 Registered: Apr 2004 posted 09-13-2006 06:42 AM                 It has been 526 days since the last post.  |  IP: Logged Marin Zorica Jedi Master Film Handler Posts: 671 From: Biograd na Moru, Croatia Registered: May 2003 posted 09-13-2006 06:42 AM                     Good subject in topic, so I won't start another topic, I just gonna ask something. Can anybody tell me a distance from center of lamp to gate??? I using 900W vertical lamp with 350mm diameter mirror, bur mirror isn't problem because i have original holders for lamp and mirror conected together, I just must set that holder to lamphouse!  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 09-13-2006 10:27 PM                     quote: Marin Zorica Can anybody tell me a distance from center of lamp to gate??? ..that's kinda of a general question due to the fact that mirror "F" stop focal lengths are so different per each lamphouse make. Some have long focal mirrors whereas others have very short focal lengths - and some depending on bulb size as well, in as well as mirror diameters.. You would have to check what are the requirements for the lamphouse used with your machines..  |  IP: Logged Marin Zorica Jedi Master Film Handler Posts: 671 From: Biograd na Moru, Croatia Registered: May 2003 posted 09-14-2006 02:43 AM                     quote: You would have to check what are the requirements for the lamp house used with your machines.. Yes I know that but nowhere I can find answer! probably because lamp house was originally made for carbon arc's and then repaired for Xenon lamps. Does anybody know a producer of mirror that gives this kind of data for each mirror?  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 09-14-2006 08:20 AM                     Conversions were done by many different people as kits as well as factory jobs and the mirrors varied a lot depending on the source you would have to find out who did or make the conversion and ask them  |  IP: Logged Marin Zorica Jedi Master Film Handler Posts: 671 From: Biograd na Moru, Croatia Registered: May 2003 posted 09-14-2006 02:29 PM                     quote: Gordon McLeod you would have to find out who did or make the conversion and ask them hmmm...I thing flying to moon is simpler to do than that I figured out stuff, distance from gate to center of lamp is 71cm, and from lamp to mirror is 10cm!  |  IP: Logged

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