flourescent lights and the cmos

[pernell91]

I'm trying to find out exactly what types of flourescent lights cause problems for the CMOS chip and its shutter. What I tend to find in my searches is references to "old flourescent lights." Will the chip be affected by the daylight corrected normal flourescent bulbs I get at home depot? What about Kino Flos? I know I can change the shutter to 40 and 60 or something but I don't want to film everything at those speeds.

[Barry_Green]

If you're using a high-frequency electronic ballast (such as Kino Flos) then you can shoot at any shutter speed.

If you're using a magnetic ballast, then you're restricted to 1/24, 1/40 or 1/60th.

[seunosewa]

With CMOS cameras, the magnetic flos might give weird results at all shutter speeds, maybe?

[Barry_Green]

If they're out of sync somehow, maybe, but I've used CMOS cameras with magnetic fluos and at 1/60 or 1/40 it works.

[pernell91]

If they're out of sync somehow, maybe, but I've used CMOS cameras with magnetic fluos and at 1/60 or 1/40 it works.

okay, so does that mean if you have just a regular screw in light bulb lamp and put those flourescent twirly bulbs in that youll be okay with a rolling shutter? as far as i know that isnt even a ballast

[pernell91]

I really am having trouble finding the answer to this without taking a CMOS camera which I don't have and pointing it at typical household lamps with flourescent screw in bulbs. It may seem like a dumb question but anyone who knows the answer I'd be grateful.

[Barry_Green]

CFLs are self-ballasted, that's why the base is so big. And the answer is: it depends on the bulb. Some of them flicker to the point where certain people can see it; I mean, forget having a camera see it, the people can see the flickering directly. Not everyone, but some people are sensitive to it.

[pernell91]

CFLs are self-ballasted, that's why the base is so big. And the answer is: it depends on the bulb. Some of them flicker to the point where certain people can see it; I mean, forget having a camera see it, the people can see the flickering directly. Not everyone, but some people are sensitive to it.

Okay thanks, so if I'm understanding, then the typical lamp is not going to be a problem unless the bulb is itself a problem. And if my eye can't pick up a flicker, then it shouldn't be any worse on a cmos camera than it is to my eye, unless it happens to be some pre-1988 magnetic ballast lamp?

[Barry_Green]

No, I wouldn't say that at all. Any magnetic-ballast fixture could cause a problem, regardless of what lamp is in it.

And you may not be able to see the flicker. Some people can. I'd dare say that most can't.

If you want to avoid the problem, force the camera to 1/40th or 1/60th shutter.

[pernell91]

Okay thanks again for the info again, i don't want to keep asking dumb questions, but is it safe to say then that the typical lamp in your home uses a magnetic ballast then, and that is why there is a risk with any flourescent bulb?

[Barry_Green]

Older fluos were all magnetic. Modern fluos are frequently electronic but may also be magnetic. So there really isn't such a thing as "typical", I don't think.

[pernell91]

Older fluos were all magnetic. Modern fluos are frequently electronic but may also be magnetic. So there really isn't such a thing as "typical", I don't think.

hm, ok, i guess just point the camera, record, sample and see if it flickers in tests for the flourescent in question. thanks again

[Barry_Green]

Yep, that's the only way to know for sure.