What is a bench focus?

[Radiant]

We recently purchased a horde of old Altman instruments - 360Q's, fresnels, and some kind of radial ERS's. Other folks used them during October for our Nightmare outreach, and now I'm about to get my grubby hands on them to add into our main sanctuary. I've read here on CB about what's called a "bench focus", but I'm not sure what all this entails. I'm supposing this would align the lamp properly? How do I go about this?
I've never really given any instruments a thorough going-over, other than re-wiring a few PAR cans. I'd like to do a good job with these new tools, as I don't know the history of them, and I'll be hanging them over the heads of people I care about. What else should be covered besides aligning the lamp? What type of cleaning should I do? What can I ignore? I'm certain there's enough instruments for me to choose from that I can pass over anything that'd be out of my league, though I am desiring to expand my knowledge of these things and learn some new skills. I fully intend to ignore the radials, as I know the 360Q's should outclass them, and we'll have plenty to go around.
Along the same line, what is the proper long-life lamp for a 360Q? Nothing high-dollar, not the high-output version. We've apparently been using some type of 1kW lamp, and I know that's not right.
If I end up needing parts, what's a good source? I know I already need a couple of sockets for some other 360Q's.

Thanks for your help and patience!

[icewolf08]

You are right in your assumption that bench focusing is centering the lamp in the reflector. On the 360Q there are 3 screws on the back of the lamp cap that can be used to adjust the center. They are in a triangle pattern, and should be slotted head screws. There should also be a center screw that adjusts the depth of the lamp in the reflector. You have to use all 4 screws in concert. To bench focus, you should set your fixture up pointing at a flat neutral colored wall or drop and get the focus as sharp as you can. Then adjust the screws to create a flat even field of light.

As for lamps for the 360Q, there are many choices depending on what you need. You probably want to look into the GLA or GLC for your 575w choices or GLE and GLD for 750w choices. We have a bunch of threads on replacement lamps for the FEL, which is probably the 1kW lamp you have been using. Try a search.

[Hughesie]

i have heard of a bounce focus

[derekleffew]

Originally Posted by Hughesie89

i have heard of a bounce focus

Hughesie, don't complicate or confuse matters.

"Bench focus" is exactly as Icewolf described: optimizing the fixture's output by aligning the lamp into the focal point of the ellipsoidal reflector. But let me elaborate just a little. The Center Screw on the 360Q lampcap is a roundhead slotted screw which also has one or two hex nuts on it also. At 120° apart are 3 flathead slotted screws. On older fixtures all 4 screws can become almost welded in place, so it's not a bad idea the day before to apply a tiny amount of penetrating oil or WD-40 on the screw threads. Be sparingly with the oil, it's going to smoke and burn once the lamp comes on. The procedure is 1) loosen the center screw about 1/4". 2) if there is a defined hot spot or dark spot, loosen or tighten the three outer screw until you get it in the middle of the beam. 3) Then loosen or tighten all three screws the same amount to make the field as even (flat) as possible. 4) If the fixture is horizontal, the lamp and socket will want to sag due to gravity, so it helps to hold in the lower screw while making all adjustments. 5) It shouldn't take any more than about five turns either direction on any screw. 6) Once you're satisfied with the results, tighten the center screw, but don't be surprised of something moves out of whack when you tighten the center screw, just correct whichever screw was not in properly and re-tighten the center screw. Then tighten the hex nuts down to prevent the center screw from moving in or out. 7) Theoretically, this process should be redone every time you change the lamp, but that seldom, if ever, happens. Once a year is sufficient in most cases. 8) While the instrument is in the bench (actually a horizontal pipe about head high is the best) is a great time a)blow the dust off of/out of the fixture using an air compressor, b)to clean the reflector using Windex diluted half with water and a soft, lint-free cloth, and c) likewise the lenses d) best to do the cleaning before the aligning, so you won't have to wait for the fixture to cool down. Also the lamp need not be at 100% during bench focus, if you have a dimmer available, run it at whatever level allows you to see the beam clearly with the worklights on. If you're in a traditional proscenium theatre, a good way is to bring the First Electric in to about 5', and then focus your lights on the cyc. You can do an assembly line, so one's cooling wile you're working on another. Or if you have help, one cleans while another aligns, and then you switch.

"Bounce Focus" has two meanings:
1) Focusing a fixture from the ground, guessing at the pan, tilt, shutters, sharpness, etc., then running the electric back to trim. Make note about what you guessed wrongly, bring the electric back in and redo, repeat until satisfied. Also known as yo-yo focusing.
2) If using a "bounce drop"--a white surface upstage of a translucent drop or scrim, bounce focus would be lights facing US, even though they're lighting the drop DS of them. Often achieve a more even wash this way.

[gafftaper]

The search function will bring up all kinds of good stuff for you including the thread "Technique for Benchfocusing 360Q's?"

Out of the 3300+ posts, this old thread contains what in my opinion is Ship's greatest hit. An old thread well worth reading by even the old dogs. I saved that post in my files for teaching purposes.

[ship]

Choice of lamp is important and one to be considered within your situation to be considered within the bounds of how you use the lamps. Lots of choices in lamp and a good start in deciding the intent of long life. Next is to refine this concept in possibly by help by way of an electrician community member or the church maintenance people. For starters are your fixtures fed by way of dimmers or switches? Architectural or theatrical control? Very important for the choice of lamps if your fixture sees realistically a 115v or 120v loading, than beyond that voltage drop and dimmer chopping. Also what dimmer level those lamps most likely will stay at?

If at full most of the time, and especially if at 120v or near that, you won’t get as cost effective a lamp life out of a 115v lamp, instead a 120v lamp would be more cost effective in balancing output with expected lamp life. Have someone check with a multi-meter the voltage at the lighting fixture, this will tell a lot, as with knowing the system. Also if you frequently go thru lamps elsewhere and it’s not fixture lamp base or maintenance related the 120v lamp would also be a better choice in covering for say voltage spikes and other strangeness.

Next is luminous output. Want the expected output of the lamp in covering for it’s maximum need in output but making that lamp get closest to the wattage needed. 400w/115v and 120v, 500w/120v, 575w/115v, 750w/115v and 120v are all available as with a TBA 375w/115v. If it’s a short throw and you don’t need to blind people, perhaps a lesser wattage lamp would be more appropriate without need to dim it much in losing color temperature. Than of course, perhaps you need max output for what you can get given the longer life intent.

That’s for the axial Lekos lamps. For the other Fresnels and radial Lekos... such a lack of lamp choice is known to the industry and that’s all I can say for now. But I recently did have in my hand and play test an experimental model of one lamp and it’s gonna set the world on fire when and if it does come to market. It’s a now known problem and coming thanks to Controlbooth and my pushing of it by way of the idea. That and the head of entertainment with that company that is a theater person and got it. Wait on those lamps for higher output given a voltage status 115v or 120v. Long life versions of these new class of lamps will follow.


Onto stuff to do when hanging over the heads of people... safety cabling each and every fixture new to you or old is absolutely necessary for all fixtures no matter the type. After that, next important is never to hang the gel frame slot up side down. In servicing these older fixtures - recommended before you use them, if you have budget send them to an expert is the primary recommendation. It’s liability. Just as you don’t make your own safety cables, unless you have an expert on staff that can sign off for this new gear inspected based on experience - don’t use them, it’s not safe to just look about it and cover your rear in liability.

There is lots of little things to look for all I would hope would recognize, little cracks in the frame that could be important, corroded lamp bases, solidly rusted sheet metal screws that sheer on testing of them, trashed reflectors not as dangerous but important, broken clutch cams etc. Above the audience or a danger to those plugging the fixtures in, this much less asbestos whips, it’s still important for qualified service people to have a look at the gear before you use it.

Such people can have a look at your gear, tell you what to fix, teach you how and perhaps sell you the parts to fix it, that’s a concept of business model or more likely they will want to supervise and or do the work themselves which is just as responsible.

None the less, ya still don’t plug in high wattage lighting gear short of inspection by people qualified to inspect it. Can read all the stuff on this and other forums you wish but it while giving hints in what to look for still won’t as also hinted at allow for eyes on the project observations. I would overall recommend you negotiate a qualified service person from the retailer in your area or large lighting company come out to inspect the gear and teach a quick fix it class for you. Otherwise budget getting the gear into them. Better yet, get into that service station where they have the tools and parts to service the gear and learn under optimum conditions.

As for parts, Altman for the most part sells all the replacement parts to their gear and it’s often standard parts with other gear, and they for parts are available on-line or thru your local Altman dealer. If no longer available Altman can advise on replacement parts or post away in this and other websites posting advice in the limited parts no longer available.

On bench focus... been discussed a few times on this forum and other forums such as stagecraft. Read the manual you can get from Altman on bench focus - if having trouble finding it, go on line to the live help and have them direct you to that bench focus manual. Than also follow the advice here on frequently inspecting where that lamp is in relation to the reflector. This by way of opening up the fixture and having a look at the results of your bench focus. A lamp hitting the reflector, than especially being torqued against the reflector is a bad expensive thing. Best to look at lamp to reflector ratio and if not even pre-bench focus by way of what the lamp looks like in relation to being observed to be centered on the reflector frequently. At that point it’s more or less fine tuning that center and working on up and down within that centered opening you will find.

Finally, all lamps for the 360Q are within a range of reasonable price. For long life in 120v the EGE and EHD are where it’s at. At 115v, the GLA and GLE are where it’s at. Otherwise for 400w, GE/Thorn does the 115v and Ushio does the 120v.

[Radiant]

Much obliged for the tips and techniques for bench focusing. I'll be giving it a shot this weekend I think.

Ship, as to what we'll be using the instruments for, we're a "rock & roll" church (though lately with a slant towards Coldplay/Emo type music). Rich, broad color washes via a dozen or so 1kW PAR64s loaded with WFL's, and 2 Mac 600's. Punctuated with 3 (4 if I can get one back from the shop) Coemar LX 250's, and blinders on occasion.

I'll be using the 360's for face light on musicians on stage. Fairly short throws, I think 12-14 feet to the ceiling. I currently have only 5 ERS's, for the lead singer, background vox, bass, keys, and drummer. [If and when the lead stands on their spot. If they don't/won't, maybe I'll move the light, or maybe they stand in the dark. It depends how much time I have before service. They've been known to rehearse in one spot and perform in another. (I've been known to turn the F-100 all the way up!)] So, I'd like to add 2 to 4 more 360's to the mix, to cover all the positions the lead may stand.

Ship, you asked what dimmer percentage I run our current ERS's at. I have two different types: a pair of 360's, and 3 of another type that I honestly don't know what they are. (I'm still learning! Maybe they're Shakespeares?) The maybe-Shakespeare on the lead, without gel or diffusion, is run around 60% at most, with a very short throw. The maybe-Shakespeares on the drummer and keys, with lavender gel, are at 80%. The 360's on the background vox and bassist, with lavender gel, are at 100%, and the output is still lacking.

The fresnels will be to add additional color washes. I'm barely getting the coverage I want from the PARs, with only two color scenes, though I think I can stretch a third from it with some repositioning. Thus far, all the dimmer circuits are in use, save one that needs repair. But, we have dimmer boxes in this new/used package also. Leprecons, I think. So I'll add those in the mix, steal some power somewhere, and have new toys.

As to the safety of the new instruments, certainly they will be hung and cabled properly. My question is the lights themselves. How likely am I to come across asbestos? How will I recognize it? There is no budget to have these instruments rehabbed by a pro. (There is no budget for lamps and gel!) So I need to know what to look for before these are hung. One positive is that these are recent purchases from a reputable local supplier. I'll check with the fellas that used them last month and get the a rundown on general condition, and find out if they were rehabbed prior to us purchasing them.

[derekleffew]

Originally Posted by ship

...For long life in 120v the EGE and EHD are where it’s at. ...

ship misspoke. It's rare, but it happens.

"EGE" above should be "EHG".

EHG is the 750W, 120V and EHD is the 500W, 120V. Both have a life of 2000 hours, a color temperature of 3000K, and have been around since the late 1970s. The FEL is the 1000W, 120V, 300 hour, 3200K, but Altman 360Qs are NOT UL-Listed for that lamp.

[gafftaper]

If you aren't sure what those other "maybe Shakespeares" are just post a picture or two and we'll figure it out.

[Radiant]

maybe-Shakespeare

They look similar to a Source 4, but with fewer features... a little more streamlined. I know they have the beam angle printed on them in white lettering, if that helps. Really I should just run up the scissor lift and read the darn things.