fresnel tilt angles at DVinfo.net

Michael Best · March 20th, 2007, 05:02 PM

Hi - if ignorant to the obvious I apologize but my ARRI's show a diagram of limited tilt angles and suggest a potential fire hazard if exceeded. While I'm willing to yield I have a scene where I'd prefer some fresnel's shooting straight down, can anyone enlighten me.

Ralph Keyser · March 20th, 2007, 05:29 PM

What size lamps are you considering? The different manufacturers do have some differences in their case designs, and the designed airflow may not function optimally in the straight down position. I've done this a number of times with smaller fresnels of numerous flavors (arri, mole, ltm) without any problem, but doing this in combination with jamming them up against a ceiling might not be smart.

Michael Best · March 20th, 2007, 05:38 PM

Well to get specific I want to hang several Desisti 2K 320's from high up in the air in a large industrial setting, I intend to use some cheater plates that
I have attached to 4X6 section of wood that will be strapped to steel girders.
It was fairly critical to have them pointing straight down but I'm very concerned obviously. Oh and thanks very much for your post..

Ralph Keyser · March 21st, 2007, 12:38 PM

Have you considered PARs instead? A 1K PAR-64 will give you pretty good punch and you can pick your beam spread to some degree by using different bulbs, and PARs are perfectly happy straight down. PAR cans are really light too, which might make your life easier for overhead rigging. I'd share your concern about the 2Ks. That's getting big enough that I'd worry about pointing them straight down if the manufacturer doesn't allow it. I'm not sure about Desisti 2K's right off.

Be sure to let us know what you end up doing.

Boyd Ostroff · March 21st, 2007, 12:56 PM

Theatrical fresnels shouldn't have this limitation, they pretty much have to be pointed straight down when hung above the stage. Check the specs on your specific unit. The warning might also be related to the lamp itself as opposed to heat coming out of the instrument. Some lamps can fail if used in a position they weren't designed for due to the construction of the base, contacts, etc.

Seeing your post, the comment about using wood to mount the units above raised some red flags. I would avoid that for several reasons. First, wood can burn. Second, it can split and cause the unit to fall. Check with a theatrical supplier in your area. They should have a variety of fresnels and mounting hardware more appropriate for your use. Or if you're dead set on using a wood block, at the very minimum use a lighting safety cable through the yoke and around the ceiling truss so it will catch the unit if the block fails. In fact, these safety cables should always be used on any overhead lighting gear. They are very cheap insurance against a possible liability nightmare!

http://www.rosebrand.com/A_Com/showd...ctGroup_ID=251

Heiko Saele · March 21st, 2007, 01:53 PM

If it weren't for the wood, I'd say just try it. If the lamp explodes inside the fresnel then there's not much damage done, but if the wood starts to burn...

From what I know there's only one thing you should never do - use wood for lighting grips...

Michael Best · March 21st, 2007, 07:19 PM

Hey thanks so much for the responses, the wood is out, only an example, I won't have any trouble strapping straight to the girders, I like the par idea but have many 2K fresnels and prefer the control. It's funny, my ARRI 150's
shed this light on me and are even restrictive tilt wise with their stand mount bracket. I'll be a good 50-60 feet in the air and the 320's with a 10" lense give a nice controllable spread. Trial and error can be fun but your posts might save me some cash and liability. Thanks

March 20th, 2007, 05:02 PM	#1
Michael Best Major Player Join Date: Apr 2004 Location: Oceanside Harbor, CA Posts: 446	fresnel tilt angles Hi - if ignorant to the obvious I apologize but my ARRI's show a diagram of limited tilt angles and suggest a potential fire hazard if exceeded. While I'm willing to yield I have a scene where I'd prefer some fresnel's shooting straight down, can anyone enlighten me.

March 20th, 2007, 05:29 PM	#2
Ralph Keyser Major Player Join Date: Aug 2002 Location: Albuquerque, New Mexico USA Posts: 287	What size lamps are you considering? The different manufacturers do have some differences in their case designs, and the designed airflow may not function optimally in the straight down position. I've done this a number of times with smaller fresnels of numerous flavors (arri, mole, ltm) without any problem, but doing this in combination with jamming them up against a ceiling might not be smart.

March 20th, 2007, 05:38 PM	#3
Michael Best Major Player Join Date: Apr 2004 Location: Oceanside Harbor, CA Posts: 446	Well to get specific I want to hang several Desisti 2K 320's from high up in the air in a large industrial setting, I intend to use some cheater plates that I have attached to 4X6 section of wood that will be strapped to steel girders. It was fairly critical to have them pointing straight down but I'm very concerned obviously. Oh and thanks very much for your post..

March 21st, 2007, 12:38 PM	#4
Ralph Keyser Major Player Join Date: Aug 2002 Location: Albuquerque, New Mexico USA Posts: 287	Have you considered PARs instead? A 1K PAR-64 will give you pretty good punch and you can pick your beam spread to some degree by using different bulbs, and PARs are perfectly happy straight down. PAR cans are really light too, which might make your life easier for overhead rigging. I'd share your concern about the 2Ks. That's getting big enough that I'd worry about pointing them straight down if the manufacturer doesn't allow it. I'm not sure about Desisti 2K's right off. Be sure to let us know what you end up doing.

March 21st, 2007, 12:56 PM	#5
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,797	Theatrical fresnels shouldn't have this limitation, they pretty much have to be pointed straight down when hung above the stage. Check the specs on your specific unit. The warning might also be related to the lamp itself as opposed to heat coming out of the instrument. Some lamps can fail if used in a position they weren't designed for due to the construction of the base, contacts, etc. Seeing your post, the comment about using wood to mount the units above raised some red flags. I would avoid that for several reasons. First, wood can burn. Second, it can split and cause the unit to fall. Check with a theatrical supplier in your area. They should have a variety of fresnels and mounting hardware more appropriate for your use. Or if you're dead set on using a wood block, at the very minimum use a lighting safety cable through the yoke and around the ceiling truss so it will catch the unit if the block fails. In fact, these safety cables should always be used on any overhead lighting gear. They are very cheap insurance against a possible liability nightmare! http://www.rosebrand.com/A_Com/showd...ctGroup_ID=251

March 21st, 2007, 01:53 PM	#6
Heiko Saele Major Player Join Date: Mar 2007 Location: Wurzburg, Germany Posts: 316	If it weren't for the wood, I'd say just try it. If the lamp explodes inside the fresnel then there's not much damage done, but if the wood starts to burn... From what I know there's only one thing you should never do - use wood for lighting grips...

March 21st, 2007, 07:19 PM	#7
Michael Best Major Player Join Date: Apr 2004 Location: Oceanside Harbor, CA Posts: 446	Hey thanks so much for the responses, the wood is out, only an example, I won't have any trouble strapping straight to the girders, I like the par idea but have many 2K fresnels and prefer the control. It's funny, my ARRI 150's shed this light on me and are even restrictive tilt wise with their stand mount bracket. I'll be a good 50-60 feet in the air and the 320's with a 10" lense give a nice controllable spread. Trial and error can be fun but your posts might save me some cash and liability. Thanks