How to use a Light Meter for Cinematography

Hi my name is Sareesh Sudhakaran and in this
video, I’ll show you how to use a light meter for cinematography. There are two kinds
of light meters, an incident meter and a spot meter. I’ll be specifically referring to
the incident meter, and I’m assuming you know what it is. Otherwise first please read
the article about light meters I’ll link to below. So, if you’re a behind-the-camera-always
kind of videographer, you can skip this video. A light meter is only useful if you can tear
yourself away from the camera and walk into your scene to measure light levels. Also, for most videography work, a light meter
is overkill. Good cameras have zebras, waveforms and an in-camera spot meter. If you have an
external monitor you can also add other tools like false color and so on. What a light meter is useful for, is to save
time when you’re lighting scenes for fictional projects. When a cinematographer enters a
scene and starts to turn on a light one by one, he or she can walk around with the meter
and measure the values at different places and get an imaginary picture of where the
levels are. This also means a certain understanding of light, of the inverse square law and how
your camera reacts to light. It takes practice and experience. Luckily for us, we have monitors nowadays
and can learn faster. Just a few decades ago they had to wait for the dailies to see if
they screwed up. So, my opinion and advice is, invest in a
light meter only if you’re interested in lighting sets and locations for cinematography.
You can stand behind the camera and use a spot meter, but the tightest spot meter is
only one degree minimum. That seems small, but even at 6 feet, one degree is about 4
inches, and its not enough to tell you the contrast ratio between the key side and fill
side. With larger sets, it gets even worse. Also, you have to always be at the camera
position to get an accurate spot meter reading. If you move away from the camera access, the
reflectance of a surface might change. An incident light meter measures light as
it falls on a space, but doesn’t care what object it is lighting. If you’re lighting
a shiny ball, it will reflect more and be overexposed, and if you’re hitting the same
light on black velvet, you won’t get the same exposure. The incident meter will give
you the same reading though. It is telling you what your light is doing, and what you
can expect as your characters move within the scene. This means, the incident meter disregards
the camera itself. When you change cameras, you’ll notice they also meter differently.
That’s because companies have different formulas for metering, and they needn’t
agree all the time. It’s even worse nowadays because if you change from Rec. 709 to Log
to RAW, the contrast ratios change. Same applies to lenses. Change the lens, and you might
get different readings. With an incident meter, you are taking away not only what is being
lit, but the camera and lens as well. This allows you to focus one hundred percent on
the lights and what it’s doing. If you add a layer of diffusion, you know
exactly what it’s doing. Add a grid, you know what’s happening. The bulb is getting
old, you’ll know it. So you can walk around your set lighting the objects in relation
to each other, without caring about anything else. That’s the key takeaway here, the
incident meter allows you to quickly set the contrast levels between different parts of
the scene. With experience you’ll know how much your key light should be at for a certain
aperture and ISO, and the rest just falls into place. So how do you use a light meter? There are
three ways. One, you keep the dome out and point it directly at the camera. This will
tell you the general exposure of the shot, because the dome reads light from all angles,
except the backlight of course. But I find for cinematography this is the most useless
method, so I don’t advise it. Cinematographers set f-stops for aesthetic reasons first, and
everything else revolves around that. The second way to read the meter is to point
the meter directly at the light, and this is the method I use. It tells the meter what
each light is doing, and you get a general sense of the exposure of the scene. When you
have multiple lights, some of them will leak into the reading of this light, and you want
that, because that’s exactly what’s going to happen when your actors move around as
well. But sometimes, you don’t want that kind
of contamination. You just want to know what one light is doing. This is the third way,
where you retract the dome so it slips inside. This way, only what’s in front is being
read. One useful situation for this kind of reading is when you want to read light levels
for green screens or flat surfaces. So that’s basically how I use a light meter.
I use the dome recessed or exposed, depending on what I want, but it is always pointing
at the lights themselves. Sometimes I cover a region of the dome with my hand to block
a certain light from contaminating the reading, but recessing the dome is easier. Finally, what am I reading? I read f-stops
and lux levels. If you’re in the US, you’re probably used to reading foot candles. One
foot candle is 10.76 lux, so there’s no voodoo there. Cinematographers learn how to
expose for their cameras and lenses by using either foot candles or lux, and no matter
what camera or lens they use, or where they are in the world, they can light an entire
scene with just one light meter, and also get some well-needed exercise. I hope you’ve found this video useful. It’s
one thing to listen to me and yet another to try things yourself. If you’re serious
about your cinematography you owe it to yourself to invest in a light meter. I own the Sekonic
478D because it’s the only meter that can read high ISOs and frame rates that are important
for modern digital cinematography, especially with a camera like the Sony a7S. If you have any questions, please feel free
to ask me in the comments below. If you liked this video and want more, please subscribe
and don’t forget to hit the like button. To get more free stuff, visit the link you’ll
see in the description or in my blog. Bye now.

61 thoughts on “How to use a Light Meter for Cinematography

  1. So a t-stop is not the same value as an f-stop right, so how can you correctly expose and set ur lens if your meter is giving you a reading in f-stops but your using a cini lens which uses t-stops. Can the meter switch between them? Also love the videos keep it up.

  2. Hello. Thanks for the video. Very instructive as always.

    Could you show us how you would iluminate a set and measure it? BTW, my Sekonik 758 do not have the LUX part… so I have to measure in F-stops. Could you include some lines on that too, please? Thanks.

  3. DUDE, THANK YOU!!!! Working on becoming a narrative cinematographer this truly helped me figure out how and why and more importantly WHEN to use a light meter. Thank you!

  4. Great video!
    Well as a "serious" hobby, I am into Super 16mm cinematography with film. I use a brand new Sekonic L-398-A, a classic for cinematography. The modern top models are expensive! The camera's internal light meter is old and unreliable. Landscapes and high contrast outdoors situations can be tricky but I am getting the hang of it. Of course with negative I try to overexpose a little (=lower ASA/ISO rating) whenever possible (= when I'm 100% sure the highlights won't get blown – negative is very forgiving here) to reduce grain and get better shadow detail. Standard procedure and no problem with a one camera setup.
    I do have trouble with direct light sources though (no spot meter included) such as night scenes (almost everything is direct light) and of course sunsets. I use expired (get it often for free from fellow enthusiasts) film stock for experiences (on film this is a very slow process anyway), but unpredictable sensitivity loss makes it unsuitable for judging the correct exposure. Haven't found anything on direct light sources with an external light meter yet.
    I know this is a rather specific topic (using old technology as a personal passion – some well known directors and DPs still do) – any tips about judging exposure with direct light sources highly appreciated. Thanks so much in advance.

  5. I wanted to ask you something a bit aside from the topic of this video. Have you worked with steadicams/vest stabilizers? Would you recommend any for a 5DMk3? Cheers!

  6. Hi Sareesh,it would be nice to have a concrete case, a clip on Youtube to show us how you measure light and take decisions on a scene in real life.All the best,Christian.

  7. Ive subscribed your channel. Your videos are great. How about making a
    video for calibrating Sekonic Light meter, example L308. Thanks a lot.

  8. I enjoy your simple and clean cut presentation and easy to understand explanation in all your videos. Thank you.

  9. This channel is one of the most useful and insightful resources for filmmaking. Thank you for producing great work to learn by.

  10. Where can I learn about the ratio's between key and fill? I find videos telling me what a light meter does, and how to operate it but not how to actually read it or use it.

  11. Hey Wolfcrow,
    I have been quitely following your work and your channel, GREAT stuff
    From your previous videos I have come to understand that to expose LOG on the sony cameras one needs to look at IRE values on an external monitor.
    It would be great if you do a video equating F – Stop on a popular lightmeter to what F stop SHOULD be depending on IRE on the Sony Cameras,
    Thus those of use without external monitors always can just do with calibrating our light meters accordingly.

  12. Thanks for explaining so clearly. I have a request. I have been trying for more deeper explanation of identifying lights based on the foot-candles read outs. I have read that for a lot of gaffers its easier with foot candles. And I have been looking for more deeper understanding regarding foot-candles. Can you please explain?

  13. Great video. I felt there are some bad videos about using a light meter on YT. This confirmed my opinion on that and dispelled some myths. There are some posers out there with a devoted (blind) following. Thanks!!!!!

  14. hi, great video!! if im lighting a interior shoot ive set my aperture to f.11 what do i need to set my lights at using a light metre?

  15. thanks for this video! I recently used the new Kinoflo diffused LED lights; it's night and day compared to any other lighting set up and it is so easy to light. I've never been satisfied with the light from regular kinoflos & diva lights; it's great, but I went back to incandescent bulbs with muslin type diffusion. You may want to incorporate these lights into an upcoming blog article or video.

  16. This video is great, and can you plz explain which lightmeter is best for cinematography for low light and higer frame rate? Sekonic LiteMaster Pro L-478D-U or Sekonic Speedmaster L-858D-U and why?

  17. I really think this video is great, he speaks with authority, factual knowledge and does not waste time with needless conversation or silly jokes nor does it appear he is operating on a trial & error bases Great!!!

  18. Hi. Could you suggest a link to purchase a light meter. Seconic 478d is not available in India and the Seconic L478d available in USA on amazon doesn't seem to have a spot meter.

  19. Good, informative video, and correct information (unlike a lot of other videos on youtube). Thanks a lot. Just got myself the Sekonic L-858D.

  20. Just a clarification. Retracting the dome and pointing at the single light does NOT measure just that light. other lights that reflect off of nearby surfaces will affect an incident reading even with dome retracted.

  21. Which is better lightmeter for cinematography & still photography? L-758 DR Or L-758 Cine. Which One? Please reply.

  22. Would you consider making a video of how to use a light meter in the field or in a mock, real life scenario? All the videos I've seen are all theoretical and somewhat abstract and still don't clearly show how you'd actually use it when shooting.

  23. You are a very good teacher— extremely clear, and you provide a great balance between theory and practical application. Thanks!

  24. I always saw the 'light-meter reader' during filming, be he the DOP, Light Designer, or an Assistant Cameraman.. as the 'king of the shoot' on the sets. He controlls the team of light-boys, grips and electricians…he directs the Operating Cameraman what to adjust on the camera settings (f-stops)…! He positions and decides not only the placement of lights and its filters/ cutters/nets… but also the tone of make-up our heroines should have! ha ha! With just one powerful tool /weapon in his hand…the Light Meter !

  25. brother, you are awesome… I have watched the video when you release it 2 years back and watching it again today 2108/Feb/13…

  26. i never needed this meter and sold it,, cause it is usefull for portrait photography when you use flash or artificial light, but not to meter the scene you are showing us, by the way this scene is overexposed that´s prove you don´t know how to do a good exposure for a scene, your white have no information. Never use a meter like this to do that

  27. I have this light meter but i am not cinematographer but rather a photographer. My question is when using nd filters how do i set the meter in order to mesure the light? Thanks

  28. Voodoo? Where’s the actual learning part ? If you’re going to do a how to video, at least get off you’re ass and demonstrate something tangible we can use.😤

  29. hey wolfcrow, how you calculate the size of the spotmeter at a given distance, you said at 6 feet the surface is 4 inches, how do you get that? it seems that you don't need a spot meter, but to evaluate the contrast in a scene between the background and the foreground how to do you proceed?

  30. Love this video. Please how do you work out what your average setting will be in your camera based on say 3 lights you have measured in a scene?

  31. I was hoping to see a video about light meter basics and fundamentals, but this is not that video. Like so many other “How-To” light meter videos, there is no up close view of the light meter display, or display scales in the case of an analog meter.

  32. No. The two kinds of light meters are Incident and Reflective. The spot happens to be one kind of reflective meter. Most reflective meters are of a wide sweep, approximating the view of the human eye.

  33. Hi thanks for your videos! I'm thinking about buying the 478 D but it doesn't read the spot light. Do you think that's a problem?

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