S4 Bench Focus Tips and Tricks

[uncmempm]

I am in the middle of the usual summer maintenance, and I could really use some tips/tricks to correctly bench focusing my S4's. I can never seem to get in right!!!

 

[gafftaper]

About the only trick is having the right place to hang them while focusing. They should be on some sort of rack or batten that is easy to reach. There should be some sort of white or light colored surface... a cyc is great otherwise a light colored wall. The instrument needs to be exactly perpendicular to the surface. You need to be able to see the entire pool of light as one perfect circle.

That's it. From there it's just...
1) sharp focus
2) loosen the outer ring to center the lamp and re-tighten.
3)Twist the inner screw to your preferred level of peak/flat. I like mine pretty flat as it keeps the light even and looks good on gobos, others like a peak spike in the middle. All depends on what you are doing with them.

Your done no real tricks. Now a discussion of Peak vs Flat preferences could be interesting and something new I believe. Anybody want to comment.

 

[derekleffew]

This document may be helpful: SourceFour Focus & Tuning.pdf. Here's a shortcut many people swear by: Remove the lamp cap and remove the lamp. Place the cap, socket side down on a table and press down hard. Tighten the center thumbscrew. Reinstall the lamp and lamp cap, and adjust as necessary.

gafftaper, the term is "cosine" not "flat": S4 Peak and Cosine Fields.pdf. I'd knock anyone upside the head who didn't keep their ellipsoidals as cosine as possible. Peak will cause you pain, every time.

 

[cdub260]

A trick I use on my Source 4's is to take the back half of the fixture, that's the reflector housing and lamp housing, and visually align the lamp at the center of the reflector. This does not complete the bench focus, but it gives me a good starting point.

 

[Lightingguy32]

cbub260, that is exactly how I bench (well center the lamps) in my units, for peak-cosine, I like cosine as well, it's a nice even beam.

 

[Lightingguy32]

Other than what has already been given I would probably aim the fixtures about 15' away from a flat white surface such as a scrim and do the benching from there. This way you can see the entire beam on a flat circular plane instead of the oblong beam you get when you are actually focusing a light.

 

[StradivariusBone]

Not to necropost, but I found this thread whilst looking up a refresher in bench focusing and sadly Derek's link to the ETC instructions is dead. I figure others might search for a similar thing in the future so here's an updated one to the S4 manual. Focusing is on page 9 of the pdf.