Bad Light - fluorescent bulbs gone bad (Part 1)
So... I have been trying out some different lighting techniques recently and I am more and more coming around to the idea of continuous lighting being awesome. Its not for every situation but I think for the bulk of my current headshot work, I could substitute the continuous lighting from florescent lights or LED packs with no downside.
There are a couple of pitfalls I ran into and I thought I's share them here.
With fluorescent lights, there seem to be 2 types you can buy in the hardware store.
1) The balast type
2) The electronic type
You will have to check the color temperatures of the individual light you buy and make note of it. In the small hardware I was in, I could find 3 different colour temperatures amongst the different manufacturers. Some are called “cool” or “warm” or “daylight,” these reference the colour of the light. Warm lights will look more orange, cool lights will look more blue. Daylight-balanced lights might actually look white, but they are usually the same colour as cool or blue lights.
Being impatient I bought 4 of the cheaper balast type tubes and rushed them home to try out. I taped them onto light stands and used my had as the all important model. The 1st picture looked great. There was a nice falloff and the light was beautifully soft. Then I kept my finger on the shutter button and shot a few more frames. Arse! This is what they talk about when they say colour change and flicker.
These are all from the same camera on Manual setting (ISO400 f4.0 at 1/320 sec) set to a fluorescent white balance. This was probably a second in difference between the first and last picture. Such a wild difference that it makes it unusable and a little bit frightening to think about the next time you are shooting in a room full of these. The only slight up side to this situation I could think of would be that if there are enough of them in a room that the flickers will be slightly out of synch and that would even out the color and intensity shifts. Then again, all AC grids will have a 1, 2 or 3 phase sine wave which may synch the color and intensity shifts which would only intensify the problem. I'd have to do more research on it.
OK so back to the drawing board.
