How to:

[Charc]

How to: Bench Focus. Okay okay, so I feel like a newbie for asking, but I've never been taught, and I feel like no one at my school knows how to do it. I just "made" 10 instruments the other day. And I'd like to know that they left my hands correctly calibrated. Okay, let me explain my I say made. My tech. program is under funded, yet I feel like we unnecessarily purchase new instruments when we can't easily use we already own. So I spent an hour playing god, and throwing together a bunch of instruments laying around. There were a variety of problems, from faulty wiring, missing screws, and a fair amount of dead lamps. I was dismayed when I found out the "problem" in two instruments was no lamp at all! Well I'm still looking around for a couple of machine screws and I need to take a look at the wiring in a couple before I add a couple more to our roster. Anyways, I wondered what the general procedure was for this. Myself, and two friends, basically just made sure the instruments would turn on, had shutters that worked, yokes, c-clamps, lamps. I admit basic stuff, but it's not like anyone else was doing it. How should we go about bench focusing these instruments before they leave elec. storage *cough* fire escape stairwell *cough*. Any help would be greatly appreciated.

[Footer]

Well, you learned a lot by doing that and hopefully didn't make any magic smoke appear. Do a search on here, there are plenty of threads about benching just about any type of fixture you could think of.

[zac850]

What type of fixtures are these? Bench focusing is making sure that the lamp sits correctly in the reflector (the focal point of the elliptical reflector) so that the light is even with no (or almost no) hot spot. Each fixture has a slightly different way to do this.

In general, focus the light on a wall around 10 feet away. Turn the light on. Focus it sharp. Find a set screw on the back of the fixture that lets you move the lamp. Wiggle the lamp around until the beam is as flat and even as it can be. Tighten the set screw back down. Unplug light. Enjoy.


And, um, last time I checked you weren't legally allowed to store anything in fire escape stairwells, something about needing them to escape fires. Just sayin............

[Van]

Originally Posted by zac850

And, um, last time I checked you weren't legally allowed to store anything in fire escape stairwells, something about needing them to escape fires. Just sayin............

Hey Lighting fixtures need to escape the fire too. They're expensive and need to be protected !

[gafftaper]

Check out this thread. The question was specific about 360Q's but there's a lot of good info in there especially from Wolf and Ship that should just about answer all your questions.

[Charc]

Originally Posted by gafftaper

Check out this thread. The question was specific about 360Q's but there's a lot of good info in there especially from Wolf and Ship that should just about answer all your questions.

Thanks, that thread was really good. I believe we have mainly 360Qs, and some weird boxy ones I've been un able to name. (I've been told they could be "centurys"). The altmans have 3 screws to adjust, the other one has a couple knobs. I found it more difficult then I expected today. I set up a shin-kicker on a table, and tried to use that as a base for focusing, but couldn't really find a place to aim it. (Those emergency escape stairs are tricky that way. But on a serious fire safety note. People that I have to train/teach in some capacity always know where the extinguishers are and not to block the firehoses. I'm considering writing a memo about not wedging the fire doors. One was being held open by... an ellipsoidal until two days ago .) I tried the ceiling, and the wall, but there really isn't a great place to aim. I also found it hard to really get a feel for the hotspot. Probably because of my background, being peppered with gray specks.

On a side note. What are your opinions on cleaning? I instruments have never been cleaned. One I set in the "to focus" pile literally has cobwebs on/around/everywhere. I'm also thinking about cleaning the lenses. Suggestions here?

[Schniapereli]

See if you can find the manuals for your instruments. These will tell you how to best clean each part of your fixtures, and standard maintenance.

If you can, you can try carefully taking apart the fixture, and wiping the lenses with a cotton cloth. (make sure it is a fabric that doesn't scratch it. some dust cloths are good for this) There may or may not be something else involved with alcohol. Don't trust me though. Read the manual if you can find a hard copy there, or one on the internet.

[Van]

Do a Search on here there was quite a thread going a while back where people were giving thier opinions on the best way to clean fixtures.
Follow the manufactureres specs as best as possible. On lens I like to use isopropyl alcohol and coffee filters. Coffee filters are lint free and non abrasive. They work great for metalic reflectors as well. Do not clean reflectors unles you know what kind of reflectors your'e dealing with. The wrong chemical might remove a uv coating, the wrong cloth might scratch.