Triming a S4

If there is a ‘trick’ without turning ONthe light I would be very surprised. The reason you need to adjust the lamp is due to the filaments ‘sagging’ over time and needing to be re-adjusted to the correct focal point within the reflector. The lamp needs to be ON in order to do this.

When ETC hung over 200 lights in the atrium of Town Square in Middleton, I helped Fred Foster bench focus all the units. It is the best way to get flat fields…so if there is a trick…Fred was not using it J

you can get the caps close with some practice, when i am doing maintenance on our caps, for various reasons, i make sure that they are set to about the same neutral point in all 5 axis. then the cap is labeled " flat field please" so the tech know that cap has been apart and needs to be tuned when installed. we do this allot, generally every light, every focus.

here are some tips

point the light straight down if possible and run the barrel all the way out. you should see the four clips that hold the reflector casting shadows, you want to see them they are going to help you find the center.

loosen the wing nut and move the lamp so that all four shadows are the same, then lock down the wing nut. the lamp is center now.

next turn the small knob, you will see the shadows get darker and more pronounced on both sides, too far in and too far out. when they are the dimmest or go away completely the lamp is in the correct place in the reflector.

take the beam to sharp and feel the glory that is a properly adjusted s4!

I would love to improve my bench tuning skills.

But... Whereas most units are not used "straight down", is it wise to tune a S4 in such a position?

I would love to improve my bench tuning skills.

But... Whereas most units are not used "straight down", is it wise to tune a S4 in such a position?

The idea is to point it perpedicular to a surface - so sat on a bench pointing straight at a wall is just as good.

Pointing straight at the floor is a direction that you can usually do even when the light is already rigged, so it's a good way to do it.

I tend to peak/flat them as follows:

• Run it up to around 75% to full. (Depends how far away the floor/wall is)
• Adjust the centre knob until the light is 'donutted' - dark spot in the middle.
• Adjust the outer knob to get the dark spot dead centre
• Adjust the centre knob until it's flat or slightly peaked (as required)