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LED lighting at a Dentist office

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Jeremy Doyle
LED lighting at a Dentist office
on Nov 14, 2014 at 6:42:21 pm

Yesterday I was shooting at a dentist's office and I experienced this from the overhead light that the dentist uses to shine on the patient. How would I have compensated for this short of just having them turn the light off?



In the wide shot it's much more subtle, but the close up...

I was shooting an Sony EX1R at 1080 30p. Shutter turned off.

Jeremy Doyle
http://www.jeremydoyle.com


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Todd Terry
Re: LED lighting at a Dentist office
on Nov 14, 2014 at 7:14:45 pm

Well, you said shutter turned "off"... so I'm not sure what means exactly, because you are always shooting at some shutter speed.

That's a pretty weird effect... but no doubt due to some sort of phasing.

That's one clear case for shooting in clearscan mode, and dialing in the exact shutter speed (which would be designated in Hz rather than in fractions of a second) to get the phasing to stop.

Sorry, I'm not familiar with that exact camera (I'm a Canon guy) so I don't know if it has a clearscan mode... but if not, you'd need a camera that does.

Or... yes, I'd just turn the light off. That's what we always do for dental or medical, but usually because the surgical lights aren't pretty lighting, and overblown. But then again we're always "faking" it and shooting procedures (dental, surgical, whatever) that aren't real. That looked more like a real scene where a real dentist was doing real work on a real patient... and I'm sure they'd want their light on.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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Jeremy Doyle
Re: LED lighting at a Dentist office
on Nov 14, 2014 at 7:19:30 pm

By shutter off, I meant it was in default mode, not one that I dialed in. It does have a clear scan mode.

I've just not experienced something that to my eye is a white light and to the camera is a rainbow.

Jeremy Doyle
http://www.jeremydoyle.com


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Todd Terry
Re: LED lighting at a Dentist office
on Nov 14, 2014 at 7:44:09 pm

Your camera can likely fix that in clearscan mode then.

Switch it to clearscan and start with a shutter speed of about 60.00Hz. Then dial it up and down until the phasing is no longer visible.

One warning caveat, though, I notice in the wide shot a visible computer monitor. It might phase at a different rate than the dental light. If the monitor and the light appear in the same shot, correcting for one might make the other one worse. You might need to adjust your framing or blocking so that you are only seeing one of those at a time. Or, if that is a computer monitor, you can go into the settings and find a screen refresh rate that matches the light (just remember to put it back, or they will call and yell at you). I didn't really notice any issues in the wide shot though.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com



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