Welding Glass for Focus

I see a lot of theatre designers who have never tried to do a focus, outdoors, at 8 am, on an east facing stage. The only way to find out where you're at is to fire the buggers at 100%, don some sunglasses, and pray.

Although I've found that pulling the bulb housing out of a leko is a good way to focus them...the sun shines through the back and gives you a better idea of where centre is.
 
On a daylit stage (but not with the sun in your eyes) you can do a pretty fair rough focus without the instruments on. As long as they don't have gel in them, you can still see right down the reflector and and lamp, and line it up that way. I spend most of my time focusing staring into the hotspot at full. Partially because you can go very fast, and partially because I've almost never got anyone there to run the board while I'm on stage, so we just punch the dimmers into test focus.

Mostly I use welding glass for checking for problems in moving lights. Very nice to be able to stare down the front of a moving light to catch any wheels that are out of place, or to pull the side of and check color mixing with the intensity on.
 
Wow. I didn't realize there were opinions on whether looking into the beam is useful. I thought everyone did it! I just find it way easier to hotspot the fixture by staring into it, rather than looking at the pool around me and trying to center it that way. Especially if I'm close to scenic elements. Also, makes it possible to do some focus work with the worklights on and such.

In any case, just ordered a piece of #10 glass from McMaster Carr. Should be here soon.

Maybe Controlbooth won't have the answer since we probably don't have many optometrists among us, but the question still stands: Is what I've been doing bad for my eyes?
 
Short answer is; Yes.
Long Answer: It depends on the wavelength of the light emitted.

Light-Induced Damage to the Retina

Overall the transmission of visible light is significantly reduced in older lenses, especially in the blue region of the spectrum. Typical daily activities are related with exposures of the retina to light levels well below the threshold doses causing acute photodamage to the retina. However, direct gazing at the sun or artificial sources of intense visible or infrared light can easily lead to exceeding that threshold, and damage the retina.

Conclusion


Visible light reaching the retina is essential for visual perception, but, despite the retina being equipped with several mechanisms to protect itself, it is easy to expose the retina to light levels that exceed these natural defences and cause damage. The life-long build-up of oxidative damage, part of which is due to light-induced damage, can contribute to the age-related changes and degenerations observed in the aged retina

Intensity of the exposure, frequency of the exposure, the wavelength (both UV & IR) of the light entering the eye all contribute to retinal damage over a lifetime. It's not enough just to protect our eyes from UV A/B. The article is rather long, but quite fascinating.
 
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Seeing as focusing lights is generally done to create a look on stage, it actually seems counter-intuitive to look into the light as you focus. I have seen and done both, and I can certainly see the benefit if you had to focus on an outdoor stage in daylight, but indoors, i would look where the light is going. Since you have to look where the light is going to get your edge and shutter cuts (or barn doors, iris, etc.), why waste the time turning back and forth. Once you have looked at enough ERS units it is easy to see the hotspot or lack thereof. This of course is besides the fact that focusing lights should be less about staring down the barrel at the lamp and more about what that light looks like as it hits you and the stage.
 

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