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Author Topic: Persistent focus problems, need advice Mark Farr-Nash Film Handler Posts: 40 From: Vernon, TX, USA Registered: Mar 2007 posted 04-24-2010 09:42 PM                        Hey folks, Been a while since I've been here. Things have been good, but I'm stumped with this one. I've got a scope lens that suddenly doesn't want to focus. It gets REAL CLOSE and then fuzzies up again. Here's what I've tried to do: I changed gates (on my machine, it's worked before with jumpy film) I loosened the lens and unwound my manual focus knob all the way back out again, and then centered it in the middle of the bolt, for the most amount of back and forth play. I checked the lens for a burn spot or a crack (and while I was there, cleaned it) I cleaned my glass plate (it was a little dusty) I have loosened up the gate a little bit (this isn't a pinching or a jumping problem, but I thought I would try it anyway) I have unscrewed the 2mm bolt that holds my outer focus ring in place and I have spent the last ten minutes trying to fine tune it from my REAL CLOSE position. I'm really at my wit's end. Up here in Vernon, technicians are four to seven hours away, so I'm used to doing this for myself, but I'm out of ideas. Any suggestions would be most helpful. Mark  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 04-24-2010 09:56 PM                     Make and model of the lens would help. If it is a schneider, particularly ones of the '80s and '90s, odds are, the elements inside have twisted. They will never focus after that until they are realigned on an optical bench. Schneider lenses of that era are notorious for this. I have not had that problem with the current generation of lenses or their integrated anamorphics, like the ES. Steve  |  IP: Logged Mark Farr-Nash Film Handler Posts: 40 From: Vernon, TX, USA Registered: Mar 2007 posted 04-24-2010 10:05 PM                        From what's on the front of the lens, the make is: ISCO-GOTTINGEN ULTRA ANAMORPHIC MC 2X 44857 Does that help? Also, do these things go bad, like grapefruits? Aside from cracking or browning, I mean.  |  IP: Logged Adam Martin I'm not even gonna point out the irony. Posts: 3686 From: Dallas, TX Registered: Nov 2000 posted 04-24-2010 10:45 PM                     Have you tried Focusing anamorphics?  |  IP: Logged Mark Farr-Nash Film Handler Posts: 40 From: Vernon, TX, USA Registered: Mar 2007 posted 04-24-2010 11:04 PM                        No I haven't. Thanks for passing this along. I'll give it a shot. Since then, I've actually changed my lenses back the way I had them. This cleared up the problem on my blurring movie in theater #2, but the focus issue moved back to theater #1. Here's what's interesting, though: now the problem isn't as noticable. It's more in focus, but now I've got what appears to be a barely noticeable halo around everything. It's as if it's trying to be 3D or something. And focusing it one way moves the images further apart. Focusing it the other way brings them closer together, but then can't quite seem to lock into focus. It's more noticable on the bottom of the picture, but it's still there. I'll run the loops tomorrow before the shows, but in the meantime, does that additional bit of into help?  |  IP: Logged Martin McCaffery Film God Posts: 2481 From: Montgomery, AL Registered: Jun 99 posted 04-24-2010 11:08 PM                        Have you looked through the lens with your eyes? The haloing sounds like water vapor may have leaked into the lens. Had it happen here once. You look through the lens and it appears either fogged or haloed. Anyway, it's an easy check before doing the above mentioned stuff. You'll have to send it in for a bench repair if it is water.  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 04-24-2010 11:25 PM                     Sounds to me like that anamorph has been dropped and has elements that are out of alignment. Send it in for repair or pick up the anamporph I have up for sale in the Equipment listings here.  |  IP: Logged Mark Farr-Nash Film Handler Posts: 40 From: Vernon, TX, USA Registered: Mar 2007 posted 04-26-2010 11:21 AM                        Update: I used my focus loop and followed the focusing anamorphoric instructions. Now, my loop is pretty damn old, but it seems to have worked just fine. I'll power it up tonight and see if it has helped. What's baffling to me is that it should all of a sudden be so OUT of focus. I've checked with my projectionists, and neither one had dropped the lens. There are no dents or scuffs on it. In fact, it's probably the only piece of equipment aside from the projectors and platter that they ARE really careful with. Is this something that happens over time, or do I just chalk it up to the charms and thrills of running an old theater?  |  IP: Logged Adam Martin I'm not even gonna point out the irony. Posts: 3686 From: Dallas, TX Registered: Nov 2000 posted 04-26-2010 04:24 PM                     Is the lens in a turret? Are the projectionists using the lens to turn the turret?  |  IP: Logged Mark Farr-Nash Film Handler Posts: 40 From: Vernon, TX, USA Registered: Mar 2007 posted 04-26-2010 07:00 PM                        I feel like a jackass not knowing to what that refers, but I'm contextualizing it and I'm pretty sure the answer is no. This is an old RCA projector that has the socket in front for the lens. It slides in, and then a couple of turns of a knob inside the housing locks the lens in place. A pin placed at the top of the housing on the outside keeps it vertically aligned.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 04-26-2010 07:52 PM                     If he's saying "RCA", bet that's the soundhead which may have an old Brenkhert sitting on top of it, or something else.. If so, it's prob an old flat-trap projector..wonder if the trap rails are getting worn to hold the film flat causing focus issues..or just a ton of build-up in the trap area which would prevent film to lay flat in the machine.... ..just some guesses .. (for when he said "RCA", first thing that came to mind was RCA 16mm units ...) _Monte  |  IP: Logged Mark Farr-Nash Film Handler Posts: 40 From: Vernon, TX, USA Registered: Mar 2007 posted 04-26-2010 09:07 PM                        Second Update: Ran the print tonight, and lo and behold, I correctly focused the thing! Picture looks great now. Now, all I need is a 2mm screw to replace the one that dropped on the floor and vanished... Wow, I used my diagnostic loop to correct the anamorphic lens, and last week, I changed the lamp out at the beginning of a show, in five minutes. ...does this make me officially a projectionist, now?  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 04-27-2010 12:49 AM                     ...more like a location booth tech/projectionist...  |  IP: Logged Sean McKinnon Phenomenal Film Handler Posts: 1712 From: Peabody Massachusetts Registered: Sep 2000 posted 04-27-2010 09:06 AM                        I beleive RCA sold a re-branded version of the brenkert (or maybe it was a simplex i don't remember)  |  IP: Logged Mark Farr-Nash Film Handler Posts: 40 From: Vernon, TX, USA Registered: Mar 2007 posted 04-27-2010 10:51 AM                        Monte, I can live with that! These forums have helped and continue to help me. Thanks to everyone who generously gives of their time and expertise to be here and post. It's places like this that re-affirm my faith in the Interwebs (and people, too).  |  IP: Logged

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