Sparking tungsten fixtures frequently

charlie ricottone · December 5, 2014

im shooting a music video this weekend where we will have 8 fresnels turning on and off around 80 times throughout the shoot, all cued by the song.

will sparking a fixture that many times in a short period deteriorate the lamp quicker than normal? i always have a couple of spare lamps in the kit, but should i have a lot more spares in this instance?

Edited December 5, 2014 by charlie ricottone

Brian Drysdale · December 5, 2014

The lamp life will be shortened if you switch on it off and off frequently as compared letting it run continuously. How long each lamp will last doing this over a shoot will depend on the age of the lamp and its use history .

Kenny N Suleimanagich · December 5, 2014

I always wondered how those fay lights used in live performance worked, the ones that go on cue. They always seemed to be on some kind of dimmer that worked quick enough to give the illusion of them striking on the cue. Maybe look into those? It’s basically your average fay-style light but rig-able to a DMX board or something of the sort.

Phil Rhodes · December 5, 2014

I was about to mention that - using a dimmer with a preheat function can greatly reduce the stress on the lamps. Often it's possible (or necessary) to adjust the preheat level to the point where the lamp's filament is just barely glowing, but not emitting any effective level of light.

This could be simulated using any dimmer - just don't turn it all the way down, but if it's cued, it seems likely you'll want a control desk and a rack of dimmers anyway, so you may get this feature for free.

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charlie ricottone · December 6, 2014

thanks everyone. that was really helpful.

charlie ricottone · December 7, 2014

just thought i would update for anybody interested. we ended up getting some cheap dimmer boxes and a bunch of spare lamps. everything went really well. we didn't need to replace any of the lamps throughout the day.

the one thing i would mention is that we rented a couple of 1k lowel dp's. they worked pretty well on dimmers, but near the end of the day started to flash around 20% brightness when dimming down smoothly. im thinking the bulbs were on their way out or the dimmer boxes were just made of cheaper components. anyways just thought i would mention it for anybody planning on using them for a similar application. maybe somebody has some insight as to why this may have been happening.