Probably one of the most misunderstood terms in beginner photography is “stop.” Imagine hearing, “I need three stops of brightness. Stop ISO 200 to 400, stop speed 1/60 to 1/30, and stop (f-stop) 5.6 to 4.” It’s statements like this, and the mathematical explanation, that make most people leave their camera on automatic and never venture into manual modes. The reality is that the math and “how it works” don’t really matter.

A 9 year old may understand how to use a microwave, but 1 in 5000 people (if that) actually understand how a microwave works. Many professional photographers have no idea of ​​the inverse square law and how it works to calculate aperture size. However, each of them understands how the stops are used. On the other hand, there are quite a few nerds out there who can recite the math, but can’t control a camera at all. The purpose of this article is NOT to explain how stops work, but rather to explain how to use them to become a better photographer.

One of the main reasons why the term halt is so confusing is that it has multiple meanings (only two of which are relevant to this article). This is going to be a bold statement and I’m probably going to get hate mail for saying this, but the ONLY IMPORTANT thing that really matters about the word tall (as far as taking better photos) is that it indicates that something is bent or cut. to the half. At our photo studio in Nashville and Louisville, we have all kinds of books and charts that talk about stops, but at the end of the day, a stop is that simple.

Memorize this: A stop means doubled or halved. 1 stop-up means duplicate. 1 stop down means cut in half. 2 light stops up means FOUR TIMES the amount of light (double, then double again) and 3 light stops down means 1/8 of the light (cut in half, then in half again, then half for the third time).

As an example, imagine you are out in the sun and you need a pair of sunglasses that will block exactly half of the sun from hitting your eyes. You might say, “Hey, I need a pair of sunglasses that block 1 step of light.” After you put them on, the sun is still too bright, so you say, “Actually, I need a pair that only lets in a quarter of the light.” In other words, two light stops. The first stop cuts the light in half, and the second stop cuts that half into another half, resulting in a quarter of the original. 1/8 is down 3 stops, 1/16 is down 4 stops, and 1/128 is down 7 stops.

In photography, this is exactly how we talk when we talk about adjusting the light. If we need to double the amount of light entering the camera, we “stop” the light by one stop. If we need to cut the light in half, we “stop” the light at a stop. If we want to let in 16 times the amount of light that’s already coming in, we need 4 steps of light (first doubles it to 2x, then doubles it again to 4x, then 8x, then 16x). Remember, each stop doubles or cuts the previous one in half.

The main reason photographers use this terminology is to have a common language for measuring light settings that everyone can agree on. (Again, I’m simplifying here, and I’ll get more hate, but I’m not a purist and this is the easiest way to understand this.)

How to really apply “one stop”.

There are three main controls on a camera: ISO (sensitivity), Speed, and Aperture. They EACH have different sets of numbers, but the only thing they have in common is that increasing or decreasing each of these controls has the effect of doubling or halving the final light. Tattoo this statement on your forehead and internalize it; This concept will completely revolutionize your ability to understand how to control the light in your image (let’s be real, without light, all your images would be pitch black and people would make fun of you).

ISO is how sensitive your camera’s film or sensor is. It is usually measured in 100, 200, 400, 800, etc. 3 light stops down (cutting your number in half 3 times from 1600 to 800 to 400 to 200).

Shutter speed is how fast the aperture opens and closes. So 1/30th of a second is twice 1/60th of a second. Because the opening is open twice as long, it lets in twice as much light. Therefore, 1/30 is one stop above 1/60. 1/240 is 4 stops less than 1/15. (Again we go from 1/15 to 1/30, then from 1/60 to 1).

Aperture is the opening in the camera that allows light to enter and is measured in what are called f-stops and the numbers are shown in a series such as 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22. Again, forget for a moment why these numbers are in this series, and remember that 11 is two steps away from 22 (here, a smaller number means a larger opening and more light). 5.6 is 4 stops below 1.4.

Putting it all together

Understanding that all three controls are in “stop” increments is the key to lighting. If you take a photo at ISO200, 1/60 and f8 and need the image 4 times brighter, you now understand that there are three options: 2 stops from ISO200 to ISO800, 2 stops from 1/60 to 1/15, or 2 stops up. from f8 to f4. Each of these decisions will have a creative visual effect, but they will all have one thing in common: allowing four times the light into the final image.