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Reading a Light Meter: Tips and Tricks


Many of you have asked me, why in this new digital age is a light meter necessary? When everything is immediate, as well as right there on an HD monitor for your review, WHY the light meter? I have mentioned in the past that Roger Deakins feels like he can be much more of a risk taker with digital. What you see is what you get. RIGHT! He has a point. When you are infusing LUTs (look up tables) on your monitor and lighting to those specs, why would you need that old light meter that reads the values of illumination?

“Building Light Memory”

The light meter is essential for matching and to get your head around light ratios as a young cinematographer. If you look on the monitor and you like the way it looks, the mood and the color tone, then get in there and read those levels and read the color temperature. These are all building blocks of your memory of light.

“Mental Snapshots”

From the time that I wake up till the time I rest my head on my pillow, I never stop looking at light. Inspiration is everywhere. I take snapshots, little instagram shots and store them in my mind. Now you have images to pull from when you are lighting a scene. Say you went to a really trendy bar and you loved the light and mood. Store that mental snapshot. When you are set to light a club/bar scene, use that mental snapshot if it fits the story and emotion of your creation. Download it into your lighting, levels, color and mood.
Lighting snapshots


Training your eye to all the ratios that you like and want to deploy comes with experience. But matching is a huge issue, especially when shooting a feature or a short film. Why? Well, so many times you are asked to go back and do pickups. Maybe you missed a shot, or you screened the movie to an audience and they were confused on some things. You need to go back to the location or the set and duplicate the light. If you did not take light meter readings or mark down the color temp of your camera, you are flying blind. I go in there once I have lit the original scene and grab as many readings as possible to help in this process. Now you have your edit, so you can go back and look at the levels and try to match what you originally shot off a monitor. Why not have this as a tool to help in this process?

“Light Meter Calibration”

Before setting off on a project, I always make sure that my light meter is accurate. The best way to simply do this is to send it to Quality Light and Metric in Los Angeles. HA HA!!! Or if this option is not available, then the tried and true spot meter test will suffice. The Sekonic L-758C is the ultimate meter because it is two meters in one. You are able to read the incident light levels with the ball and the spot meter function gives you the ability to read points of light, the wall and buildings in the deep background to make sure there is enough fill level, grey cards, etc.

Let’s try this. Take one light and aim it at an 18% grey card. Once you have done this, you can now read the grey card with the spot meter. Turn your incident spot selector dial to spot meter mode and fire it at the center of the grey card.
turndial incident
Once that level is acquired (we got a 5.6), you now turn the incident spot selector dial to incident meter mode and now read the key light that is aiming at the grey card.
turndial spot
Incident card
Our reading came up 4.0 9 10ths, which is basically a 5.6. So we now know that our meter is calibrated perfectly.

“The Process of Reading Light”

There are many tried and true ways to read a light meter. Let’s first set up your meter so that it matches the ISO to your camera’s ISO, the frame rate you are shooting and your shutter speed.
Setting ISO 320
Setting ISO 500
shutter speed
Ok, we have our meter set to the correct ISO, shutter speed and frame rate. Now we are going to discuss how to read light. I have tried to include everything you will need to know on how you aim your meter and how you position your hand.

“Day Exterior Work”

Reading Sky Light
To read ambient sky light, I hold my meter straight up at the sky.
Reading Sky Light
Cupping Sky
Then I cup my hand around the ball.
opposite sun
This is how I keep my balance when the sun is dropping and I need to manicure the top light fill levels. This is so essential when you have lost the sun. Say you run out of time and you now have to cheat a close-up or an insert. This will give you that level to be able to create it with artificial light.
The other reading you have to grab before the sun escapes and pounds itself into the horizon is your ambient fill light level that is opposite the sun. You need to capture this level to again match all the sunlight that is bouncing off walls, trees, etc. while the sun is setting and to also use if you have run out of light.
light bouncing
To do this reading you turn your meter opposite to the sun. Then shade the sun off the top of the ball and cup your hand around it slightly. The final reading to achieve is what the sunlight is reading. Turn your meter towards the sun and hit the button to get this reading.
sun reading
I cup the ball slightly to take out any unnecessary bounce light and sky top light.
cupping outside
I find it absolutely essential to calculate in my head what the stop difference is between the sunlight and the ambient fill light. This ratio between the two exposures will be how you balance the light as the sun sets as well as using this ratio to light any close-ups or inserts that you might not have had the time to grab while the sun was up. Trust me. This will happen to you because it has happened to me about a thousand times. You cannot stop the sun from setting. I have tried all my life to achieve this, but have failed.

“Interior Stage Work”

Reading a Key Light
demo set-up
We have designed a lighting set up to help you see the subtle nuances that the light reflects into the incident ball. Our fill light is slightly cooler and a circle bounce which will be easier to see. The key light is a rectangle source and slightly warmer in tone.
ball reflections
Our backlight is one of my baton lights and this will reflect 12 bulbs in the ball.
backlight demo
When reading a key light, you aim the light meter directly at the source. Put your meter right next to your actor or stand in’s face and cup your hands around the ball so that it is not getting influenced by your fill light or backlight. I look into the ball to see if I am seeing the fill light reflected in it. If I do, I cup my hand in a way that blocks this so that my reading of the key light is accurate.

Cupping your hand around the light ball is an art in itself. If you cup your hand too much, it restricts the light meter reading.
reading key
Sometimes I just put my hand up to block the other light that I do not want to influence the meter, so that I can take in as much of the key, back or fill light as possible for an accurate reading.
blocking reflection
This is one way to cup your meter.This is cupping your ball to read only the key light and taking the fill light and the backlight off the ball.
cupping the ball
This is another way to cup the ball, surrounding it a little more.

“Reading a Fill Light”

Reading a fill light is just like the key light. Look at the reflection in your meter and make sure the only light that you see reflected is the fill source. I have made it a little easier by making the key light warmer than the fill light. That way we can show the coolness is all that is hitting the incident meter’s ball, as well as the shape being round, not a rectangle.
fill light reflection
Fill Reading
Now you have the basics of reading light and my technique. Reading light is so essential to your creation as a cinematographer. Now get out there, read light, and take those mental snapshots. Stay tuned for a post on how to read a color temperature meter.

The Sekonic L-758Cine DigitalMaster Light Meter is my choice, but there are other Sekonic light meters at different price points to get you started. Links to B&H are provided below.

Sekonic L-398A Studio Deluxe III Meter
Sekonic L-398A Studio Deluxe III Meter
Sekonic Illuminometer i-346 Light Meter
Sekonic Illuminometer i-346 Light Meter
Sekonic L-308DC DigiCineMate
Sekonic L-308DC DigiCineMate
Sekonic Litemaster Pro L-478D Light Meter
Sekonic Litemaster Pro L-478D and L-478DR Light Meter
Sekonic L-758Cine DigitalMaster Light Meter
Sekonic L-758Cine DigitalMaster Light Meter


Thanks to Filmtools Rentals for supplying the Sekonic L758Cine Meter.
Shot at Revolution Cinema Rentals in San Fernando, CA.
Thanks to Paskal Lighting for donating all of lighting and grip equipment.

Model: Monette Moio

Author: Shane

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  1. Great article! Having used light meters for many, many years I knew much of what was said, Still there was a tip I had not been using! Thank you!

    I have had a Sekonic L-398 Studio Deluxe since the seventies always ready never not out of batteries ;) Great piece of kit!

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  2. Thanks Shane for the info. Wished I had this yesterday as I did my first lighting scene ever on a corporate. I had to balance 2 dedo’s and a softbox to tungsten lighting in a hospital office but somehow it was nicely lit but lacking depth, if that makes sense. I think I will try and find a used light meter if that’s wise.

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  3. Awesome stuff Shane, thanks for sharing. I have a Luxi that I use with my iphone for a cheap light meter.

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  4. Though I can light decently without a light meter I find my workflow is much more efficient with one. Having the light meter allows me to explore the set untethered to camera or monitor. If you depend solely on the monitor and waveform you are limited to where the camera is positioned at that moment. Something which (even though a lot is planned in advanced) unnecessarily limits room for creativity and adapting quickly on set. With a light meter I can relight or tweak while the camera is being repositioned or if there is some sort of technical difficulty.

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  5. Wow, I never knew there were so many ways to cup balls.

    All joking aside, thanks for providing everything you do on this site Shane. It’s been really helpful for someone like me who tries to absorb as much as I can while I get my feet in the industry.

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  6. Amen Brother! Love seeing this article. Ultimately a light meter is a tool that encourages previsualization as opposed to a kind of “plug ‘n chug” approach you may get by lighting to monitor; you end up with the look you want instead of a look that’s ok, but maybe not what you had imagined.

    Thanks again for the inspiration.

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  7. one thing that is most impotent is how you calibrate the meter to specific camera ISO and specific gamma?
    i know that different gammas at different cameras put the 18% grey in different places at the scope.

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  8. Hey Shane, thank, as usual for the great info!
    Question: I imagine you more-or-less know what kind of aperture and/or shutter speed you want going on for a scene before you shoot, and the ISO is usually a derivative of the other two factors(please correct me if I’m wrong)- is there a way for say just reading the meter at 100 ISO F2 180 shutter angle(example), and then plugging the resulting reading into a formula with the desired aperture or shutter speed to get correct exposure with those settings?
    Hope this wasn’t too confusing…..

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    • Mind when comparing both incident and reflected light on a 18% grey card, that its reflectance actually is still 18%. If the readings don’t match, it doesn’t necessarly means your meter is not properly calibrated. I’m posting this especially for students. Sometimes in schools, cards are old and their characteristics change in time. Compare light meters and ask the card to be changed if necessary.

      Also, when using a video camera with a built-in autoexposure system, mind that these systems are not necessarely calibrated for an 18% value so that checking the exposure on such a card won’t work (usually you can set this in the menus)

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    • Eli — If I understand your question, you’re asking about exposure values. Each f-stop number, for example, is the equivalent of doubling or halving your exposure depending on the direction you’re going. So if you wanted to open up your aperture one stop (more light coming in) you’d cut your exposure in half to keep the exposure value the same. You can do the same with ISO — each doubling or halving of an ISO number is the same as opening or closing one stop. So if you were one stop underexposed at ISO 100, f4, Shutter Angle 180, you could double the ISO and leave your f-stop and shutter angle alone. (This beautiful bit of mathematics, of course, fails in the face of noise at high ISO values, which will make your image fall apart.)

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  9. Shane, thanks for the info. I noticed the two shots of you turning the dial to the appropriate mode are inverted (1 and 3). The dial setting in image 1 doesn’t match the dial in image 2. The dial in image 3 doesn’t match the dial in image 4. They seemed to have been misnamed so they’re correct in sequence but incorrect as far as the images go.

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    • Thanks for pointing that out, Brian. We’ve got them moved around correctly in the post now.

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  10. Shane-

    Instead of cupping the meter ball, have you tried just leaving the lumisphere retracted and aiming towards the light source you are trying to meter. What are you thoughts on that method?

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    • benj, I am fairly old school with this. I have trusted my readings the way I have been doing it for over 20 years and I expose based on that. These are the things that if the wheel is not broken don’t fix it kind of things

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