Measuring Light and Achieving the Correct Exposure

Get the measure of light with this simple class.

How do you measure the power of the light from your studio lighting to ensure perfect results? Do you apply visual, theoretical, histogram or light meter readings to achieve the best results?

Karl discusses the best ways to measure light and achieve the desired exposure as well as the limitations of the above methods and why it’s important to truly understand light if you want complete creative control.

In this class:

  • Different methods for measuring light
  • Light meters — what use are they in digital photography?
  • Assessing exposure visually
  • Combining aperture and shutter speed to achieve desired exposure
  • Reading histograms
  • Correctly exposing for different textures

Questions? Please post them below.


  1. Gary Stasiuk

    These lighting classes are great. So far I know most of your presentation but you literally go through everything in great detail so any vacant holes are filled. Such a great resource. I have a strobe meter which I haven’t used since rekindling my studio lights and going digital. I realized, while watching this that I should sell that thing before it is completely worthless. Enjoying your content and most importantly, learning.

  2. Hi Karl, thank you so much for these classes – they are fantastic.

    I shoot mostly digital, but I’ve recently been more curious about film photography. I’m wondering if you would recommend getting your strobes dialed in with a digital camera and then adjusting the settings to match on your film camera to achieve the same exposure (as opposed to using a light meter)?

    1. Hi Casey, that’s one way of doing it but film doesn’t always come in the same as digital. So for example you could be shooting 100ISO EKTACHROME and 100ISO on digital but they’d look differerent because of latitude of the shadows/highlights and even the exposure may vary. If you’re going to shoot film it is best to use a lightmeter and run tests on the film and lights and light-meter measurements and note down the results for future reference. Back when we used to shoot film we also had polaroid backs for the medium and large format cameras, so we’d swap backs and shoot polaroid tests until in the ballpark. The polaroids were pretty well balanced to match the film but not 100% either. You have about 1-2 stops latitude of error with negative film and about 1/4 stop latitude of with transparency film. Meaning you can still get a good print out of negative film if your exposure is a little off but not so much with transparency film.

      1. Thanks so much for your thoughtful reply Karl. That’s helpful to keep in mind – so much more to explore with film as well!

  3. These videos are absolutely brilliant and worth every penny, I’ve learnt loads already. I first got into landscape photography a few years back and spent most of the time trying to just capture natural light, on the few occasions where I actually needed to use lighting I was pretty much clueless!! I was sceptical about clicking on this video as the thought of using a light meter also seems odd to me, though after the first few minutes you’ve grabbed my interest again!! Thanks so much, and keep up the great work!!


  4. Hi Karl,

    Many thanks for your amazing classes, I am learnings lots from you and today, after this chapter I decided not to buy a light meter, thanks for the advise. I am still a beginner and I am having problems with the settings of the camera to use the lights. In this chapter, you didn’t say anything about shutter speed and that is one of my main problems. Did you use HSS?

  5. Hi Karl, good explanation.

    I suppose to use a light meter is like using TTL in the flash. You can use it as a start point and after it you change the parameters to obtain the result you want.

    Regards from Spain.

  6. Not used a flash meter for a long time but when I did – 1980s/90s, the advice was around direct or reflected meter readings. Would a flash meter work more accurately if it measured reflected light in the way the camera does?

    1. Hi Matthew, no not really although flash meters can measure incident or reflected, the reflected setting is still based on the same 18% grey reflectivity as camera light meters so it will struggle with pure white or dark black objects. The best advice if you wish to use a light meter is simply use it to get you in the ball park and then put it down and focus on using your eyes and creative vision to make the rest of the decisions.

  7. Hi Karl,

    Really loving all your classes and learning so much every day!

    I do believe that sometimes too much technology can hinder your creativity. My question for this class is, does this mean we should not reply too much on the light meter in the camera as well? I just started using manual mode after taking your course, and when I set the aperture and don’t use the light meter, I really have no idea what shutter speed to use, so I usually read the meter, and take a test shot first. Sometimes even when the meter shows perfect exposure, the photo is actually over or underexposed, so I will then adjust the shutter speed regardless of what the meter says, and I believe after shooting manual for a while I will be more familiar with what shutter speed to use even without reading the light meter. I wonder is this is the right way? Thank you!

    1. Hi Miya, glad you are enjoying the courses. Yes it’s absolutely fine to use the camera’s built in light meter to get you in the ballpark and then work it out from there. Like you say at some point in the future you probably won’t need it as you’ll start guessing what it needs to be and as you also said you’ll often find it’s not accurate anyway so simply use it as a guide and nothing more.

  8. derrick_connell


    I joined today, and this was my first video. I have a light meter and have been feeling guilty about owning it and not using it. I have been using my own eye and aperture, and this video has reinforced my choice.

    Time to head back to the camera store and sell my light meter!

    I am very excited about the possibility of creating images similar to the examples you provided in this module. The paint photo is stunning – and something to aspire to.

  9. Agree with the points–only thing is that I shoot with 8×10 Large Format, and by virtue of using film for the kind of work that I do, a light meter is necessary.

    On that note, what kind of tips in terms of measuring/metering light creatively can you share given that I am shooting table top still life.

    Appreciate it, and +1 to creative intent at the forefront of making decisions.

  10. Of course, I agree a light meter is imprecise, which is why I’ve always preferred using a spot meter (and I still do as I mostly use B&W film), but I disagree with the statement that it gives you the “wrong” exposure; just like a spot meter, it gives you the aperture, for the iso, time selected, and current flash power/ambient light, in order to correctly expose a middle gray card, nothing more, nothing less. Once you understand that, how all these parameters relate to one another, and understand the zone system, you can make all the creative decisions you want, and combine multiple readings to evaluate contrasts, these decisions have never been taken away from you. And I have to say this is one of my great pleasures in photography, but I certainly am awfully old fashioned 😉

    But yes, with modern digital cameras, thanks to histograms, light meters are unnecessary, there’s no debate here, and shooting tethered is even better when one can.

  11. “You need to think of lighting as a column control on your music system…turn the power up and it gets louder, turnout down it gets quieter….” BOOM!!! #moneysworth #Brilliant
    LOVE this course

  12. I’ve never had a light meter but for some reason decided this week that I was missing out on something.

    So of course I went online and ordered one.

    I’m sure I’ve watched this video before but thankfully at some point today, I happened upon it again and it reminded me that I don’t need a blasted light meter.

    Was able to cancel before it shipped and saved myself a couple hundreds which can now go towards some other gear …… 🙂

    1. Hi Simon, if you mean the 30×120 softbox pointing at Stiffanies neck and side of her head, then yes that is flash as well.

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