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3 Steps to Actually Using Your Light Meter

Laura Beth Feb 25

Why are Handheld Meters Still Important?

Sure, the dirty secret is that a lot of us go days,
or even entire shows without consulting our handheld meter. 

LB Love DP - My Light Meter Most work is now digital, and most professional cameras have fantastic internal meters, so it is possible to skate by without a handheld meter.

BUT, the one place that a handheld, incident meter beats an internal meter, hands down, every time, is when you are pre-lighting a set, or lighting for a move where the camera will turn a corner… basically, anywhere the camera can’t see. 

The internal meters of your Red can’t leapfrog to the next set to get it lit in advance! 

Therefore, a professional cinematographer (and gaffer) needs a handheld meter.  We all know it.  We may not use it everyday, but we have it at the ready.

However, I know many aspiring DPs and gaffers who own a meter and never use it, because they don’t really understand how to use it.  They bought it because someone told them they should, but…  They don’t see how it fits in to their workflow on set, it’s intimidating, it slows them down… eh, fuck it. “The pros don’t always use them either.” Right?

You will need  your meter one day, so let’s get on it.  🙂  It just starts with practice and comparison.

Follow these three steps to start using your meter.  You can begin to intuit patterns as you “calibrate your brain” by comparing it against the internal camera meters you currently use to determine exposure.

3 Steps to Actually Using Your Light Meter:


1.  Enter Your Settings.

Your light meter needs to know a couple of things before it can give you accurate readings:
(If needed, read the instruction manual for your specific meter)

  •  Shutter Speed- How long will the shutter be open?  (How long will the sensor, or film, be exposed to light?)  Your meter may have settings in fractions, seconds, and minutes. 
LB Love DP, calculating shutter speed

Calculating Shutter Speed

***The meter will not have separate places for shutter angle AND frame rate, if you are running slow motion or “undercranking” you may need to do some math to determine shutter speed.

(Example: 180˚ shutter at 48 fps.  If the shutter is rotating 48 times for second, then it would be open for 1/48 of a second.  However, a 180˚ shutter means the shutter is closed for half of each rotation.  That means our shutter speed will be: 1/48 divided by 2 = 1/96.

Sometimes your camera will tell you shutter speed, but it’s good to know how it’s calculated so you can trouble shoot if something “goes screwy.”

  • ISO –  Make sure the ISO setting on your meter and camera match!  For film, the ISO is printed on the label on the can.  Most professional digital cameras now have an ISO setting in the menu or sometimes directly on the body.

If your digital camera doesn’t have ISO settings, you can determine its ISO one of 2 ways.

  • “Offset” Settings
LB Love DP, mattebox and filters

Are you using filters?

Are you using any filters?  In particular, ND, Polarizer, and Color Correction filters will affect your exposure, and therefore you need to account for this when you take a light reading.

For example, an ND.6 filter will cut out 2 stops of light.  You have the choice to keep that in your head, and remember to open up by 2 stops after you take your light reading, or you can plug it in to your digital meter so that it will automatically offset the reading by 2 stops for you.

If I’m using a filter consistently, I’ll opt for the offset.  But, if I’m regularly changing filters, I’ll usually just keep it in my head.  It’s entirely your preference.

Either way, you have to pay attention!

lightmetering2.  Measure.

Take an incident reading:

Hold your meter in key light, press the button, and see what it says.

If you are not using any filters, and don’t have any other reasons to adjust, that’s your T-stop!

While your meter doesn’t know what you are shooting (it actually assumes you are shooting a grey card), the idea is that if you place the “grey card” in proper exposure, then objects brighter than 18% grey will be placed appropriately brighter in your exposure, and darker objects will be placed appropriately darker.

In reality, it’s a great starting point.  You might just be finished!  Exposed!

3.  Think About It.

Your meter is properly set up and you’ve taken a reading in your keylight!  Now, you get to move on to the more creative, subjective part of determining exposure.

  • Look at the rest of the frame.  Take more readings with your hand meter, and compare them against your key light.
    Are the dark areas dark enough?  or too dark?
    Are the bright areas bright enough, or too bright?
    Does the range of exposure in important details, from light to dark, fall within the dynamic range of your camera?
    If the answer to any of that is “no,” adjust all the other light and shadows relative to your key.  Use the handheld light meter as your tool for measurement.
  • Internal meters on the Red Epic - histogram, "goal posts" and "stoplights"

    Internal meters on the Red Epic – histogram, “goal posts” and “stoplights”

    Check your internal meters.  You will almost always want to keep using internal camera meters, even after you learn how to use your handheld meter.  And why wouldn’t you?  It just means you have a built-in back up for checking exposure!

All of the different types of meters give slightly different types of information.  The more you learn about exposure, the more you’ll want (and be able) to consider as much information as possible when determining your best exposure.

  • Consider your subject.  Your meter doesn’t know what you are shooting.  In fact, it assumes you are shooting a grey card!  If you are shooting a white room full of white objects, you may choose to underexpose a little to help retain highlight detail.  If you are shooting a black room full of black objects, you may choose to overexpose a little to help retain shadow detail.

However, remember that adjusting your iris to blanketly over or underexpose the image only protects detail, it does not fix your lighting ratios.

Make sure that the black areas are black, and the white areas are white, and try not to use your iris to “fix” a lighting problem.  The lighting problem won’t go away.

For example, if  you have some important dark objects against a dark wall  and  you choose to overexpose in order to “see” the objects, you’ll likely just end up with the same problem in post.  When the dark wall is brought back down to the appropriate level, the important objects will be too dark again.

In this case, it is more likely that you need to adjust your lighting to create a value difference between the objects and the wall so that they appear to have separation or different reflectance values, and fit within your camera’s dynamic range.
We are seeing more and more extreme power-windowing attempting to bring impossible exposure ranges into a single frame.  Sometimes, it looks pretty fucking weird.

And sometimes worse: boring and flat.


Practice.  More Research.  Practice Some More.

After you’ve been using your meter a while, come back and read this article again.  Or re-read other research that you’ve found.  The more you practice, the more the research, tips, and tutorials will start to make sense!

Then practice some more… and research some more…  this is a never ending cycle in the career of a cinematographer!

Best of luck!  And let me know how it goes!  Subscribe to this blog for email updates!

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Copyright © Laura Beth Love and LBLove.com, 2015. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Laura Beth Love and LBLove.com, as appropriate, with appropriate and specific direction to the original content.


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  1. Paul Hara February 9, 2019

    Wonderful advice about when to use that expensive meter I bought!
    Thank you!


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