Traditional Light meter really not ideal for LED lights?

[Wenqi Wei]

Hi guys, I don't seem to find the answer anywhere else so I decided to post here.

My question is as the title suggests, in this era where LED dominates so many lighting scenarios, even those really high-end Hollywood productions, do these light meter, say a Sekonic 858, no long works with these LED lights? I can't imagine Hollywood DPs throw away their light meters and light only with in-camera or monitors' WFM/False color/Zebra etc.

I'm also aware that LED lights emit more blue lights and so on, but is that relevant here?

Please drop your comments and thoughts below, thanks! 

[Wenqi Wei]

I forgot to mention, what I meant was when these DPs/Gaffers tried to set up a scene or when they do pre-light or just in general maintain lighting consistence from shot to shot, not while shooting, which I believe they can sort of 'eyeball' the exposure. Any thoughts?

[David Mullen ASC]

I hardly use a meter but it's not because I don't think it would be inaccurate under LED lighting, maybe it would under a very narrow wavelength of saturated color. But even if it were inaccurate under that condition, it might be consistently inaccurate, enough to help with matching levels shot to shot. 

I usually have the DIT grab frames of the master and I then compare my coverage to see if the look has drifted in terms of balance, color, etc. But when lighting the coverage, I usually start by having the lens set to the same f-stop as the master and often I'm not changing the background lights, just the foreground.

But for pre-lighting a set before the camera would be there, you would work with a light meter or your gaffer might, at least to get to the base f-stop you hope to use. It's less critical today since digital cameras have a range of ISO settings they can work in.

[Wenqi Wei]

David thanks for your insight. Yeah I understand to decide the working stop, it would require a light meter. But I still want to know if I take a Incident reading under LED lights, is that reading still considered valid/trustworthy?

[Kamran Pakseresht]

Yes it works the same, light is light - I have been using my sekonic l398 with my aputure 200d light and it’s just as accurate as when I use it outdoors or really in any other lighting conditions.

[Joerg Polzfusz]

Hi!

All LEDs are emitting visible wavelengths. And the lightmeters are reading visible wavelengths, too. Hence, I don’t see any problems. (The lightmeters also don’t become inaccurate when you put colored gels in front of your halogen lamps - unless you are using orthochromatic films, infrared films/cameras or sensors that don’t react to certain colors.)

However, due to the spike in the blue wavelengths in many products, LEDs might have an impact on the color temperatures. But you would have to check this with a color meter.

Edited September 29, 2023 by Joerg Polzfusz

[Phil Rhodes]

Funnily enough I was just thinking of getting a better meter. I only have an old Sekonic L-398A, and much as it's a classic design, the direct approach of simply connecting a solar panel to a moving-coil voltmeter doesn't work at the sort of low light levels typical of current practice. The aim would be to improve consistency, given I'm more often working on a tiny crew without a dedicated DIT.

I don't want to spend a fortune but I think something is in order. Don't even really know what the field contains.

[Wenqi Wei]

Hey guys thank you all for posting.

Yes I always believe light meter should NOT go extinct just because of this new LED trend.

I had this thread because I came across this article the other day and began thinking: https://ledlightinginfo.com/can-a-lux-meter-measure-led-light I guess I will just take a grain of salt when dealing with this in the future.

Thank you all again, very much appreicated for the discussion.

[Adrian Sierkowski]

8 hours ago, Phil Rhodes said:

Funnily enough I was just thinking of getting a better meter. I only have an old Sekonic L-398A, and much as it's a classic design, the direct approach of simply connecting a solar panel to a moving-coil voltmeter doesn't work at the sort of low light levels typical of current practice. The aim would be to improve consistency, given I'm more often working on a tiny crew without a dedicated DIT.

I don't want to spend a fortune but I think something is in order. Don't even really know what the field contains.

See if you can find an L508 on the cheap or a Minolta IVF. I have both and they are lovely.

Be advised though they will be about 1/10th of a stop off as I believe Sekonic is set to 12% grey (or the Minolta maybe?) Though that's a trivial discrepancy.

As for LED lights; I have no qualms about getting light quantity on any format from any light with a meter. However, if I was shooting film with cheaper LEDs I would really want to use a high end color meter as in that particular case (where you can't easily see a final image) the discontinuous spectrum of some LED lights might be problematic if you're going for a neutral color look. If you're going for something "ugly" or "urban" or "rough" then this is much less of a concern (akin to the old days of pure sodium vapor lighting at night)

[Michael Hammond]

All I can say is what I've seen from experience, and that experience tells me the light meter I use is always right with LEDs. I haven't run tests but my footage and my false color in editing says it's all good.

 

[Ed Conley]

From the linked article:
'If you’re a keen gardener, then you’ll probably want a PAR meter instead. They’re more expensive, but they specifically measure the wavelength of light needed for plants to photosynthesize."

the article is directed at Grow operations ?