Guest lightnix Posted May 2, 2006 Share Posted May 2, 2006 This is something that's been bothering me for some time, but has caused some issues for a colleague recently in the shape of a dissatisfied client who didn't like the "fuzz" around their gobo-projected logo (even with a doughnut). He is responsible for a fair stock of lamps, including a number of S4 zooms, both 15-30 and 25-50. Over the years (just like other profile spots) their sharpest focus has gradually developed a haze around the edge of the beam, making them increasingly unsuitable for text / logo projection. A number of things have been tried, including asking the manufacturer and... Doing the lamp alignment "by the book" (whatever that means)New lenses (the old ones had the AR coating taken off by the Wrong Kind Of Cleaner - be warned!)New reflectorsLamps from different manufacturers ...all to no avail. More irritatingly, there are two "special" zooms which can still be focussed as crisply as ever and have suffered no ill effects over time (these are hidden in a secret place, away from the daily hurly-burly). Does anybody have any clues as to what is going on? One thought that just entered my head is that maybe the black paint on the inside has faded / changed somehow, so that it's more reflective, although this is pure conjecture. Link to comment Share on other sites More sharing options...
woody74 Posted May 2, 2006 Share Posted May 2, 2006 Does anybody have any clues as to what is going on? One thought that just entered my head is that maybe the black paint on the inside has faded / changed somehow, so that it's more reflective, although this is pure conjecture. I've run into this, and one solution is to take the back-cap completely apart, lube or graphite the mechanical parts of the focus, and put it back together. The cap has two parts (one circle inside another) and they should move fairly independantly from each other. That last part sounds vague as I read it, but hopefully the take-apart-put-together bit helps. -w Link to comment Share on other sites More sharing options...
ampcats Posted May 2, 2006 Share Posted May 2, 2006 In the past I've always put it down to filthy lenses, but it seems to be fairly common... I know to somebody it is sucking eggs, but for those that don't know... the source 4's bulb focus knobs are 2 part - grab the outer knob, turn anticlockwise (loosen) 1 turn, this unlocks the position (y and z axis as viewed from the side). hold the inner knob and move it (don't turn) so bulb is centred in the reflector. tighten the outer knob. this locks the y and z axis turn the inner knob to adjust the x axis (how far into the lamp the bulb is) the coating inside seems to last well, but would be interested to hear if ETC have anything to say about it... Link to comment Share on other sites More sharing options...
woody74 Posted May 2, 2006 Share Posted May 2, 2006 I'll add: doing all this while shooting at a smooth, flat surface perpendicular to the axis of the fixture. And if you unscrew the smaller knob first to give yourself an obvious hot-spot, it's easier to center the lamp. After the fact, flat field is about two turns counter-clockwise of full tightened (small knob again). All of this is well and good, but if the focus has been messed with multiple times, things can get out of alinment internally and, by taking it apart, you have a chance to re-seat everything back to neutral. Ours are going on 5 years old, and they get about 300 days a year use; they get to the point where you get halo-ing at the bottom of the field and no amount of focusing and aligninig will correct it. And in some, we'll get shadows from the clips holding the lenses in...so we call the technique "reseting the cap". -w Link to comment Share on other sites More sharing options...
Guest lightnix Posted May 3, 2006 Share Posted May 3, 2006 Thanks for the input chaps, but as mentioned, this does not appear to be a line-up issue. My colleague has been in touch with ETC about this more than once and everyone is satisfied that the line-up has been done correctly; it's actually the lack of a solid answer from the manufacturer that led my to post this (mainly to satisfy my own curiosity). Link to comment Share on other sites More sharing options...
woody74 Posted May 3, 2006 Share Posted May 3, 2006 and everyone is satisfied that the line-up has been done correctly Absolutely; and you can flat field and refocus until you pass out, but I'll put money on my solution: take it apart, graphite, and reassemble. Got a pay-pal account? -w Link to comment Share on other sites More sharing options...
MattH Posted May 5, 2006 Share Posted May 5, 2006 I have read an ETC tech document (I think it was supplied with some new reflectors), that states that there is a maximum optimum live for a reflector, after which point performance drops off. However, I know of two S4's that exhibit the halo and lens clip problems and have not improved despite new lenses & reflectors. I thought this was due to their age (original source fours), but maybe this is not the case. Would ETC care to provide any thoughts on this? Matt Link to comment Share on other sites More sharing options...
Stu Posted May 5, 2006 Share Posted May 5, 2006 However, I know of two S4's that exhibit the halo and lens clip problems and have not improved despite new lenses & reflectors.I reckon about 10 out of my 12 S4 36s are giving me this problem, no matter how much I take them apart and put them back together it doesn't solve it - also have tried the resetting of the lamp base. Would ETC care to provide any thoughts on this?Would love to know how I can solve it! They are fast becoming quite embarrasing.... Stu Link to comment Share on other sites More sharing options...
ampcats Posted May 6, 2006 Share Posted May 6, 2006 QUOTE(MattH @ 5 May 2006, 11:08 PM) ...(I think it was supplied with some new reflectors).... it is in Source 4 Reflectors price comparison it says... The Source Four Ellipsoidal and Source Four PAR MCM reflectors should perform within specification for a minimum of five years and the Source Four PAR EA should perform for a minimum 7 years .... well remembered MattH.... I reckon quite a few S4's are hitting the age limit now... doesn't seem to help Stu though... Link to comment Share on other sites More sharing options...
Stu Posted May 6, 2006 Share Posted May 6, 2006 well remembered MattH.... I reckon quite a few S4's are hitting the age limit now... doesn't seem to help Stu though...Thanks for the link, interesting read. I replaced a broken reflector last year in one of our S4 36s, so I'll dig it out (I bet it's in the rig this week tho!) and see if that one is any better off - should be by the theory anyway. Stu Link to comment Share on other sites More sharing options...
ampcats Posted May 6, 2006 Share Posted May 6, 2006 Stu - would be interested in your findings... Link to comment Share on other sites More sharing options...
MattH Posted May 6, 2006 Share Posted May 6, 2006 Having re-read the topic title, it made me think that what is at stake is not just a sharpness issue. Infact, with ours a hard edge open gate looks fine, it's when you start shuttering that you get double edges at the corners of the cuts. When you throw the focus, you get the lens clip image and any cuts in the field distort, rather than become soft edge. This problem seems to be most prevelent when using 36 degree lenses, because of the two lens system seems to amplify the aberation. Consequently, soft edged cuts are always acheived by focusing hard with frost... m Link to comment Share on other sites More sharing options...
Stu Posted May 8, 2006 Share Posted May 8, 2006 Stu - would be interested in your findings... I had a chance today to go through all of our S4 36s - the one with the brand new reflector is optically far better than the other 11 (which have reflecters dating back to purchase, circa 1997)... I took one of the worse culprits completely apart (including the lamp base) and rebuilt it to no avail. One thing I've just thought off that I might try tomorrow is putting the new reflector assembly onto the 36 lens tube with the 'worse optics' (for want of a better way of putting it) and see if that improves it, or anything similar. Stu Link to comment Share on other sites More sharing options...
Guest lightnix Posted May 8, 2006 Share Posted May 8, 2006 ...with ours a hard edge open gate looks fine, it's when you start shuttering that you get double edges at the corners of the cuts...Yes, same here - fine with an open, hard beam. It's the shuttered, irised or gobo hard edges that show the halo. How easy is it to replace the gate assembly in an S4 spot? It's about the only thing that hasn't been swapped out so far :( I had a chance today to go through all of our S4 36s - the one with the brand new reflector is optically far better than... I might try... putting the new reflector assembly onto the 36 lens tube with the 'worse optics'...Stu - would be interested in your findings...Waiting with baited breath here, too. Thanks for all the input so far :o Link to comment Share on other sites More sharing options...
Stu Posted May 8, 2006 Share Posted May 8, 2006 Yes, same here - fine with an open, hard beam. It's the shuttered, irised or gobo hard edges that show the halo. How easy is it to replace the gate assembly in an S4 spot? It's about the only thing that hasn't been swapped out so far :(Thats what happens with ours too. Our S4 10s and 19s are fine tho, mind you they are much newer (2002ish I think, sorry I can't be precise but they pre-date me) and are the Mk2 versions. Very intrigued by all of this :o When you say the gate assembly, do you mean the shutter blades etc? If so easy enough, remove the lens tube then undo the 4 screws on the tube, and the 4 springs holding the shutter plate in. The tube should then split in half and you can remove the plate etc. Hope I've got what you meant! I'll let you know when I know anymore. Stu Link to comment Share on other sites More sharing options...
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