They don't seem to do it as badly. I've taken a few slow-shutter speed shots of gear for the b/s forum here, on my CF-lighted dining room table, and haven't really noticed it. Interesting question.
I will do a test for you on Tuesday when I get back to my lab at school. The "big tubes" do pulse at 120 Hz; sounds like a Light Saber when probed with a fiber-optic optical receiver. They definitely shift their incomplete spectrum during the transition.
The ones I have in my sockets do have a 60hz refresh rate, and I think that may be fairly typical across the board. Shows also on the box a 2700K (soft white) WB Temperature, the ones in the garage I use the 5600K (daylight). Indoors where I "Know" there is the use of CFL and/or Mixed lighting, I use a very low power of flash to to even out the light mixture and if my shutter speeds are in excess of 1/100 the effects of the cycling lights are not noticable or distracting...
I will do a test for you on Tuesday when I get back to my lab at school. The "big tubes" do pulse at 120 Hz; sounds like a Light Saber when probed with a fiber-optic optical receiver. They definitely shift their incomplete spectrum during the transition.
Edd
I thought lights in the US cycled at 60HZ and in Europe 50HZ?
Yes, Compact Fluorescents use an electronic ballast that operates at about 20,000 HZ or higher, so unless you are using faster than 1/20,000 exposure, you are ok. Modern ballasts are also electronic and work with 32 watt T8 tubes to give flicker free light.
As to color, they are available in a wide range of color temperatures. They do not usually have a high CRI, but you can get 98% CRI T8 tubes which are wonderful, I buy them by the box of 25 and use them extensively for photography.
scalesusa wrote:
... They do not usually have a high CRI, but you can get 98% CRI T8 tubes which are wonderful, I buy them by the box of 25 and use them extensively for photography.
Where do you get them (the 98% CRI T8 tubes)?
BTW, another related situation (relevant to the original post) arises when shooting under fluorescent light with a computer-monitor included in your frame. The refresh rate of the monitor combined with the cycle of the fluorescent light from the larger tubes can become tricky!
I believe that these are the ones. It says they are being discontinued, I should buy another case, I guess. They have had a long life so far without discoloring.
I'll have to double check and make sure these are the same ones.
I find the 5000 K color to work very well with all my digital cameras.
I have a lighting table with 12 48 inch lamps, a 4 tube fixture standing vertically on each side angled 60 degrees toward the rear, and four tubes above. I also have white fabric over the fixtures which diffuses the light, so I get no reflections. This is used for product photography, not for people.
That graph looks like a small ripple on a 1V signal and perhaps you have exaggerated it to make it look awful. But that's very different from a lamp that goes all the way to 0 on every cycle.
The CFL pulse, not turning completely off during the transition during the zero crossing regions. The lamp was sampled with a fiber-optic receiver that has a 100MHz bandwidth, used for analog testing purposes. We broadcast full-bandwidth color video over it so, WYSIWYG!
The circuitry converts 60 Hz AC to DC and then chops up the DC into little pulses.
So your graph of the light output shows the small 60 Hz residual that remains after the AC is rectified. And it shows the tiny, very fast pulses riding on the AC ripple. If you had measured the electronics, you would have seen a high frequency square wave with the little bit of 60 Hz on it.
There should be no visible flicker because most of the 60 Hz has been filtered out. I don't know why you call this "older style" because it's new style. There are no zero crossing regions because it's basically a DC voltage.
We paid less than $3.00 for each of the CFL's, so these may not be representative of what "quality" products are out there. Nevertheless, it was clear, both from a purely visual and audible standpoint (we ported an output to an amplifier/speaker), that 120 Hz pulsing was present. I would like to see some high-end units, just to satisfy my interest in the differences.
So, to answer the OP's question; yes - but it depends...
Take a picture that proves your claim. If you're correct that should be trivially easy. You have not done that. Nobody in the world has done that.
The answer to the OP's question is NO. Your own data proves the answer is NO.
You made up a story about zero crossing regions without proof, and with data that contradicts your claim. To say nothing about the beat frequencies where I am biting my tongue to keep from screaming.
Back in the 60s an integrated circuit with two transistors cost so much that only NASA or the military could afford them. Now, with $3, you could buy enough of them to pave your driveway, or buy a CFL bulb with a rectifier and frequency multiplier.
