Key Terms: Aperture, Shutter, and ISO (Camera Lesson 01)

Summary: Ryan covers the first three crucial camera terms: aperture, shutter, and ISO.

Length: 8:32 minutes

Video Lesson

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“Are you ready to go out and start shooting in 4k, while you over crank at 36 frames, on an 85mil, at a T4?”

Camera jargon can sounds like a foreign language when you’re just starting out- Fortunately it really isn’t that complicated – anyone can learn it. In this video I’ll be covering the first three of what I consider to be the six essential terms you need to know.


The aperture is the hole or opening in the lens that controls how much light ends up on the sensor. It is the ratio of the focal length of the lens, over the size of the aperture. You control the aperture either by physically moving the lens, or by dialing it in with a wheel on the camera. As you change the aperture, you are changing its size, which is why the numbers change too. It is expressed in either F-Stops or T-Stops.

When it is expressed as an F-Stop, it’s telling what the mathematical equation is at that point. T-Stops, on the other hand, are a physical measurement of the transmittance of the lens; so how much light it is actually letting through. Because F-Stops are a ratio and not a measurement, there can be variations in exposure levels when using F-Stops. If you want everything to match perfectly in exposure level, then you want to use lenses that have T-Stops, since that is an exact measurement of how much light is actually being let through.

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Depth of Field, Part 1: How Aperture and ISO Affect Focus
Your Guide To High Speed, Part 6: Five Tips For A Successful Shoot
Your Guide To High Speed, Part 5: Lighting Six High Speed Sets
Your Guide To High Speed, Part 4: Common Lighting Problems
Your Guide To High Speed, Part 3: Camera Operation & Workflow
Your Guide To High Speed, Part 2: Frame Rate
Your Guide To High Speed, Part 1: Introduction
12 Crucial Questions Before Lighting Your Set (Cinematic Lighting Lesson 15)
Negative Fill: The Best Kept Secret (Cinematic Lighting Lesson 08)
12 replies
  1. masterlegend
    masterlegend says:

    I have a “gain” setting and it is measured in decibels. Is this equivalent to the ISO setting and how would I convert that if it is?

  2. Will
    Will says:

    Hey Ryan & Tim, really enjoying the first lessons on the course. As per your recommendations I’ve invested in a Sekonic l-478dr and am just trying to find my way around it. I’m shooting on a GH3 with a older Nikon photo lens so I’m manually changing the f-stops on the lens.

    On the camera lens I’m using the F-stops go f2, f2.2, f2.5, f2.8 etc

    On the light meter (using the T function) the F reading is a large 2.0, then a small number next to the 2.0 such as 2.0 (small 6) and then the next large number is 2.8

    I assume these smaller numbers are increments of light change between the stops?

    My question is:

    Is there a way to change the light meters setting to match the 1/3 stop markings on the camera? so they also read f2, f2.2, f2.5, f2.8 etc

    Thanks for your time.


    • Ryan E. Walters
      Ryan E. Walters says:


      Thanks- glad you like the lessons, and congrats on getting the meter. 🙂

      You are correct- the small number is an increment- it is actually 1/10 of one stop. So a read of 2.0 4 is 2 and 4 tenths of a stop.

      To get your meter to match the reading on your DSLR, Press the MENU button, select #3 (Custom Setting), Select #1 (Increments of T+F) and then change it from 1 stop to 1/3 stop. Now it will read like your DSLR read out.

      Happy Shooting. 🙂


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