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14 – Language of Stop

Beginners should come back to this section later.

1 – Note

This language analogy makes it easier to understand an essential concept in photography.

However, the language of stop is this writer's concoction.

So, if you take a photography class, don't ask your teacher about it.

2 – Introduction

There is a "language" in photography that is called Stop.

Stop is "spoken" everywhere in photography.

3 – Encouragement

Again, because Stop is the language of photography, you'll be a better photographer if you can "speak" Stop.

I encourage you to read this section a couple of times.

You'll be rewarded with a better understanding of how your photography works.

4 – Definitions

The basics of the language of Stop are easy to learn.

One Vocabulary Word

The language of Stop has only one word: Stop.

Definition of the Single Word

The definition of stop:

A stop is a quantity of light.

Grammar of Stop

The "grammar" is very simple:

2X

When you add a stop of light, you're doubling the amount of light.

1/2X

When you subtract a stop of light, you're decreasing the light by half.

Let's see how you can put the language of Stop to work for your photography.

5 – Grammar Example #1

If you have a stop of light, you have a quantity of light.

Here, one stop of light is represented by a box.

If you add one more stop of light, the amount of light doubles.

If you add yet another stop of light, the light doubles again.

Let’s subtract some stops.

If you have one stop of light . . .

. . . and you subtract one stop of light, the amount of light halves.

If you subtract yet another stop of light, the amount of light halves again.

That's the grammar of Stop: 2X and 1/2.

We've been looking at Stop abstractly.

Let's see Stop in action with a photograph.

7 – Photograph Example

Here's an example of the language of Stop with a photograph.

Let's say this picture was taken at f/8.

To vary the exposure. we'll be changing the aperture.

The shutter speed will remain constant at 1/250th.

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f/8

The exposure on the next photograph was changed by one stop: f/8 to f/5.6.

The amount of light has doubled.

The photograph is brighter—by one stop.

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f/5.6

Here's the first photograph again, taken at f/8.

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f/8

The exposure on the next photograph was also changed by one stop: f/8 to f/11.

The amount of light was halved.

The photograph is darker—by one stop.

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f/11

Now let's look at how Stop is "spoken" by three countries on your camera.

8 – Three Countries

Stop is spoken by the three "countries" on your camera.

They countries are:

1) ISO

2) Shutter speed

3) Lens opening

Cameras have always had globalization.

The three countries are interdependent, and they all "speak" Stop to each other.

Let's look at how Stop is spoken in each country.

Stop & ISO

ISO is one of the countries on your camera.

ISO 800 is more sensitive to light than an ISO 100 setting.

You can take photographs in dimmer light more readily.

But you don't have a sense for how much more readily, unless you speak Stop.

Stop gives you the answer: 3 stops more readily.

Let's go from ISO 100 to ISO 800 using Stop.

ISO 100 to ISO 200

ISO Doubles

1 Stop More Sensitive

ISO 200 to ISO 400

ISO Doubles

1 Stop More Sensitive

ISO 400 to ISO 800

ISO Doubles

1 Stop More Sensitive

The total change is three stops.

An ISO 800 setting is three stops more sensitive to light than ISO 100.

So?

Stop & ISO Example

By understanding that an ISO 800 setting is three stops more sensitive than ISO 100, you now know that you can use a shutter speed that's three stops faster.

Let's say, with an of ISO 100, you're photographing a horse at twilight.

The horse is called Second Chance.

There's enough light to use an exposure of f/4 with a shutter speed of 1/15th of a second.

ISO 100 f/4 1/15th

1/15th of a second is a slow shutter speed.

Second Chance, the horse, will be blurry if she's moving.

And, you'll get blur from camera shake.

So, you switch to ISO 800.

The sensor is now more sensitive to light.

So, you can use a faster shutter speed—three stops faster.

ISO 100 f/4 1/15th
ISO 800 f/4 1/125th

Here's how to count the number of stops in this example.

ISO 100 to ISO 200

ISO Doubles

1 Stop More Sensitive 1/30th

ISO 200 to ISO 400

ISO Doubles

1 Stop More Sensitive 1/60th

ISO 400 to ISO 800

ISO Doubles

1 Stop More Sensitive 1/125th

Second Chance will be sharp.

That's because you're able to use 1/125th instead of 1/15th.

You were able to change the shutter speed by three stops because you changed the ISO by three stops.

Now, let's look at how Stop is spoken in the country called aperture.

10 – Stop & Aperture

Aperture is the second country on your camera.

If you change the aperture by one stop, the light either doubles or decreases by half.

How many stops difference between f/4 and f/22?

The aperture is getting smaller, so the amount of light will decrease.

f/4 to f/5.6

One Stop Less Light

f/5.6 to f/8

One Stop Less Light

f/8 to f/11

One Stop Less Light

f/11 to f/16 One Stop Less Light
f/16 to f/22 One Stop Less Light

By going from f/4 to f/22, there are five stops less light reaching the sensor.

Let's look at how Stop is spoken on the last country, shutter speed.

11 – Stop & Shutter Speed

If you move the shutter speed one stop, the light reaching the sensor either doubles or decreases by half.

How many stops difference between 1/500th and 1/60th of a second?

1/500th to 1/250th

One Stop More Light

1/250th to 1/125th

One Stop More Light

1/125th to 1/60th

One Stop More Light

There are three stops difference between 1/500th and 1/60th.

There are three stops more light reaching the sensor.

We've looked at how Stop is spoken within the three countries.

It was mentioned earlier that the countries trade stops back and forth.

12 – Trading Stops

ISO, aperture, and shutter speed, "trade" stops between each other.

The photographs below look the same, exposure-wise.

That's because aperture and shutter speed traded stops.

q
f/5.6 1/4000th
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f/8 1/2000th
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f/11 1/1000th

The above photographs look the same because the same amount of light—the same number of stops of light—reached the sensor in all three photographs.

Yet, the apertures and shutter speeds below each photograph are different.

Again, aperture and shutter speed traded stops.

Below, bar graphs are used to represent the amount of light that reached the sensor.

You can see that the bar graphs are the same length.

That's because, as mentioned, the same amount of light reached the sensor in each photograph.

But, less or more light came through the aperture and the shutter, depending on how the two countries traded the stops between themselves.

q
f/5.6
1/400th
q
f/8
1/200th
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f/11
1/100th

The exercise on the next page will help you to fully understand Stop.

13 – Moon Exercise

A flower bed was photographed with the light of a full moon.

The photograph looks like it was taken in daylight—because daylight was used.

That is, the sunlight reflected off of the moon was the light source.

We expect light from the moon to be blue.

That's because film makers use a blue filter for day-for-night scenes.

q

Click Photograph to Enlarge

The exposure was as follows.

ISO 1600 f/8 60 Seconds

How would the above numbers change if we "trade" stops between the three countries?

Let's change the ISO from 1600 to 100.

That's a four stop change:

1 Stop 1 Stop 1 Stop 1 Stop
1600 to 800 800 to 400 400 to 200 200 to 1002

We have to trade four stops.

Let's trade between ISO and aperture.

The new aperture is f/2.

1st exposure: ISO 1600 f/8 60 Seconds
2nd exposure: ISO 100 f/2 60 Seconds

We traded four stops from the ISO to aperture:

f/8 to f/5.6 to f/4 to f/2.8 to f/2

The ISO is now four stops less sensitive.

The aperture now gathers four stops more light.

1 Stop 1 Stop 1 Stop 1 Stop
f/8 to f/5.6 f/5.6 to f/4 f/4 to f/2.8 f/2.8 to f/2