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SLRs - the unRF For those of you who must talk about SLRs, if only to confirm they are not RF.

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This is a bit weird
Old 03-29-2017   #1
Shac
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This is a bit weird

I'm sure one of you at least can explain it but this morning I had a strange experience. I was checking the metering accuracy of a new-to-me body against some I had already. Every meter acted strangely - some read outs flickered (R7, F3, EL2), others gave a strange read out (F2AS). Only the M6 seemed OK.

Finally figured out the cause. I'd recently replaced my kitchen lights with LED units. Move away from their influence and presto! no meter problems.

However, it's not all LED lights. My Dracast LED studio light causes no such problem. So I assume unlike the kitchen ceiling lights it has some kind of "supressor".

Any suggestions welcome (other than to not photograph anything in my kitchen )
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Old 03-29-2017   #2
Timmyjoe
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The newer lighting sure does effect photography. Used an LED light source with my shutter speed tester and it threw it all out of whack. And the new lights (not sure if their LED) in high school gymnasiums cycle through white/orange/green. They look like white light to the naked eye, but when shooting high speed sequences, the first image is white, second orange cast, third green cast, then back to white and repeat.

Not sure there is much we can do about it, just the nature of the beast.

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Old 03-29-2017   #3
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There are a lot of reports how Chinese-made, el-cheapo LED lights interfere with FM/AM radio and all sorts of other electronic devices. Apparently, installing ferrite chokes on the cables as close to the LED as possible helps.

I recently replaced the driving lights on my Jeep with LEDs and now the reception on my car radio is very poor.
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Old 03-29-2017   #4
Shac
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Thank you both. The kitchen lights are cheapish ones made across the Pacific.
I guess it's not surprising that the Dracast studio lights are OK
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Old 03-29-2017   #5
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LED lighting is a real problem, especially with cheaper ones. You can actually see artifacts with the naked eye if you wave your hands fast enough under them. This effect was already there with fluorescent lighting, but with LEDs it's even worse.

Recalling that there was something about that with my DSLR, I dug up the manual, and lo and behold, there's even a flicker reduction setting there. Apparently the camera can recognize the 50/60Hz cycle and adjust itself to prevent banding in movie/live view. Seems it doesn't know what to do for stills though..
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Old 03-29-2017   #6
Steve M.
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Your last question is your answer. Unless you are photographing the bulbs or are otherwise close to them, you will have no problems.
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Old 03-30-2017   #7
Shac
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Thank you Peter
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Old 03-30-2017   #8
sevo
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Thanks to their lower power requirements and DC operation, the electronic ballasts in LED lamps are creating much less problems than the electronic ballasts in CFL lamps and modern FL tube fixtures did - my encounters with flickering LED light are rare, while that used to be given with fluorescent lamps of all types and generations.

In your place, I'd go over the kitchen installation - chances are that you use a dimmer incompatible with the lamps used. Just like fluorescent, LED lamps are a complex load, and as such not dimmer proof unless explicitly stated.
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Old 03-30-2017   #9
farlymac
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LED powered road signs are another quandary. I go with the slowest shutter speed I can manage, depending on the type of camera.

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Old 03-30-2017   #10
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An eye opening thread. I thought they were more constant it sounds.....

Does speak well for shooting B&W all the time....

Any of the more knowledgeable folks share a link where we can learn more about the nuances of LED lighting?

Thanks.

B2 (;->
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Old 03-30-2017   #11
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Largest problem is that they are not driven with a DC current, so in reality they go on and off at high speed. No problem for the eye if above 50/100 Hz but a camera that goes to 1/1000 sec is faster. The same can happen with "white" leds that are not made with an UVled and a phosphor but that consist of a red/green/blue led. Nice because you can adjust the colour (temperature). But if they are cycled then you get that different photos will have different colours.
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Old 03-31-2017   #12
sevo
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Quote:
Originally Posted by Spanik View Post
Largest problem is that they are not driven with a DC current, so in reality they go on and off at high speed. No problem for the eye if above 50/100 Hz but a camera that goes to 1/1000 sec is faster.
The higher frequency, the smaller the converter can be. Usually LED converters are using 35-50kHz - that is still out of the range where RF shielding is mandatory, and high enough that even the first subharmonic is not audible any more. At that size, it is trivial to filter to pure DC, so well-designed and -made lamps should not flicker at all, at any frequency (none of the replacement LED bulbs and tubes here do). But cheap ones may be poorly filtered or use no proper conversion.
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Old 04-01-2017   #13
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Fascinating.
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