Conventional Fixtures ETC Source Four Zoom Template Issue

[cantic1]

I have 6 ETC Source Four Zooms (15-30 degree). One unit in particular is giving me problems maintaining the sharp/soft focus of a template once it is inserted. For example - the gobo I was using was focused as sharp as it possibly could be, matching its counterpart. When the light first came up, the focus was fine. But after about 1 minute of being on (at about 60% intensity), the gobo lost its focus and would soften out. The other unit maintained its focus, so this obviously was a very noticeable issue.

Once the light was off for a scene, it would go back to its original focus when it was brought up again, but just as before, would lose its focus after about 1 minute of being on.

I swapped the unit out for another working zoom, and when I opened up the problem unit, I couldn't see anything visibly wrong. Has anyone else had this issue? I'm pretty certain it is some kind of heat issue, I just can't figure out exactly what.

 

[Phantom_Sandwich]

Just curious, are you using metal or glass templates?

 

[cantic1]

Just curious, are you using metal or glass templates?

Metal. They're standard Rosco Steel Gobos. Same pattern in both.

 

[Phantom_Sandwich]

Just a thought, but try swapping templates to see if it follows the fixture or template. My theory being it may have something to do with the heat causing the metal to warp a slight amount giving it a different focus. Are you using a sandwich style holder?

 

[cantic1]

Just a thought, but try swapping templates to see if it follows the fixture or template. My theory being it may have something to do with the heat causing the metal to warp a slight amount giving it a different focus. Are you using a sandwich style holder?

Ah, I'll give that a shot. I just find it odd that its only happening with one of the units. And yep, it's your basic Rosco sandwich style gobo holder.

 

[SteveB]

Sounds like the zoom lens train is slipping. This happens if the unit is focused at a steep'ish angle. I know there's a way to tighten the lens adjustment system, but the ETC website is in shambles right now and I cannot find the zoom manual.


Sent from my iPad using Tapatalk

 

[Phantom_Sandwich]

I was thinking the same thing as SteveB at first, but if its out of focus and then back into focus, I don't see how it would "re-achieve" proper focus. HOWEVER, definitely check into that as well, as my thoughts are just conjecture.

I have personally had problems with those sandwich holders and getting gobos to stay in properly, everything kept slipping. Thinking maybe the gobo has a little "play" with the distance inside the sandwich holder, from my experience, every mm counts when focusing. Found these bad boys from Apollo:

http://www.internetapollo.com/Products/View/1771.aspx

I haven't had a slipping or loose gobo problem since; so happy I found them.

 

[SteveB]

The gobo is going into the gobo slot ?, not the accessory slot ?. The gobo slot is right tight against and in front of the top shutter. I know, I know you probably know this, doesn't hurt to ask.

 

[RonHebbard]

I have 6 ETC Source Four Zooms (15-30 degree). One unit in particular is giving me problems maintaining the sharp/soft focus of a template once it is inserted. For example - the gobo I was using was focused as sharp as it possibly could be, matching its counterpart. When the light first came up, the focus was fine. But after about 1 minute of being on (at about 60% intensity), the gobo lost its focus and would soften out. The other unit maintained its focus, so this obviously was a very noticeable issue.

Once the light was off for a scene, it would go back to its original focus when it was brought up again, but just as before, would lose its focus after about 1 minute of being on.

I swapped the unit out for another working zoom, and when I opened up the problem unit, I couldn't see anything visibly wrong. Has anyone else had this issue? I'm pretty certain it is some kind of heat issue, I just can't figure out exactly what.

Hello c1;

Possibly a bench focus issue, with the problem fixture running a little hotter in the centre than the problem free unit.
I'm suggesting the gate temperature is hotter / more problematic on the troublesome fixture warping the gobo.

Toodleoo!
Ron Hebbard

 

[Kelite]

A warping gobo is my thought as well- standard Rosco steel patterns are just .005 thick. The intricacy of the artwork could worsen the problem as well.
A gobo holder that securely holds the entire circumference would likely help, and Phantom_Sandwich makes a valid point! And the SuperHolder has a lifetime warranty on the handle in case of drops-

 

[cantic1]

I like the look of those gobo holders! I'll have to check them out.

Thanks for all of the suggestions, everyone. I tested it with a few different gobos and am still having the same issue, so it seems to be a problem with the unit. Hadn't thought of the bench focus hot spot as an issue, I'll have to take a look at that next. Since the gobo loses focus, then goes back into focus after cooling down, I'm almost certain it has to be some kind of heat issue.

 

[Phantom_Sandwich]

A warping gobo is my thought as well- standard Rosco steel patterns are just .005 thick. The intricacy of the artwork could worsen the problem as well.
A gobo holder that securely holds the entire circumference would likely help, and Phantom_Sandwich makes a valid point! And the SuperHolder has a lifetime warranty on the handle in case of drops-

Keith, you should be advertising those things, I have been telling everyone about them, and every single person has told me they wish they knew about those a long time ago. After many years of slipping gobos (such a pain to have to go through all adjustments and SLIP!), I can finally sleep well at night (if I am not working...)

 

[Kelite]

< I can finally sleep well at night (if I am not working...)> So... if you're in the 'booth late at night and all's well, are you snoozing?

Good point though, Phantom_Sandwich. The tricky part of the whole advertisement scheme is figuring the return on investment with different media spots. These SuperHolders are indeed that, and they work very, very well. A number of rental houses have inventories of these US made gobo holders and we've had positive feedback.

I, sir, appreciate you offering these as a solution to the original poster. Well played!