What is a Stop in photography? Is it the same as f-stops? How are they measured? Are they counted in the same way for different exposure adjustments? Are they useful?
These are probably the most common questions for those starting out in the world of photography. And they are great questions, not least because all the concepts of a good exhibition can leave anyone very confused.
For those who have already been presented with the term, the information that a Stop can mean double or half the light proceeds.
But you’ve probably never been told how it all works in terms of camera settings.
This article aims to show you how the Stop concept serves as a common currency for the exhibition, and allows you to fully control it.
And that this coin is much simpler than you think, as it is a tool for simplifying thinking.
From the start. What is an Stop in photography? And what is it for!
I am using the term “common currency” to describe what Stops are. And to better illustrate the analogy let’s imagine that we are talking about money.
If you sell chickens, I sell apples, and someone else sells bricks, as we all understand each other in doing business.
What if the person who sells the bricks didn’t value their chickens as much as I did?
Surely everything would be a big mess. And then the concept of money came up.
With this common currency concept, now we can all value our items based on them.
And as we well know, it is not today that depending on the concept of money, for more than one aspect of our lives.
In the same way that we entered an impasse with bricks VS chickens, in the photograph we have an impasse between the size of the aperture VS the shutter time for example.
Or how to value these two in relation to the sensitivity of our sensor, or film, to light?
It is not for nothing that here comes the concept of common currency, or Stops, which will balance everything!
This is all a prerequisite for mastering your camera and controlling its exposure.
Understanding this is a necessary precondition for mastering the camera and controlling the exposure process.
We hope that this will help you to better understand your exposure controls. First, let’s take a brief look at each one and show how they are measured at stops. After that, we will start using them together.
The shutter speed is a measure of time. As you probably already know, when you open the shutter, the camera is collecting, receiving, light directly on the sensor or film.
And to see better how it works I suggest you read this article here ;
The segments in this graph are 1 Stop increments. Again, a Stop refers to allowing twice as much light to enter, or cut it in half.
Remember that the shutter speed is a measure of time, so doubling the time the shutter is open is the same as doubling the light.
So, for example, a movement from 1 / 250th from a second to 1/125 is a change from a Stop.
You have doubled the time the shutter is open, so you have also doubled the exposure value.
Something that can confuse you is that your camera does not change the settings (each click on your dial) in 1 point increments.
Most cameras are configured to move in 1/3 point increments. So instead of going from 1/250 to 1/125, each click on the dial on your camera will only move part of the way.
And depending on how your camera is configured it can take up to 3 clicks on the dial to reach 1 complete stop.
Now let’s look at this in the concept of openness. As you probably know, the aperture is the hole in the lens that allows light through the camera, and that it is adjustable.
Making the hole bigger you allow more light to enter the camera; And by making it smaller you allow less light to enter.
Aperture measurements can be quite confusing. To begin with, this measurement is actually the size of the aperture compared to the focal length, where the F of a lens is the ratio of the focal length divided by the diameter of the aperture.
This makes it a reciprocal relationship or figure, which means that the larger the opening, the smaller the measurement will be and vice versa.
Second, different lenses have different maximum and minimum aperture values. With that in mind, here are the most common aperture values:
Again, remember that your camera is probably configured to change values in 1/3 stop increments.
So, for example, your camera does not go directly from f / 5.6 to f / 8.0. Instead, it will probably go from f / 5.6 to f / 6.3 then f / 7.1 and then f / 8.0, while you click the dial.
I am ignoring the concept of depth of field here because it is not important for the purposes of this discussion.
All that matters now is to convert these measurements into Stops. So, what we have done here is to convert a size measurement into a Stops.
This means that we can easily compare it to the changes in shutter speed as we saw above. We will also be able to compare it to the changes in the ISO.
Finally, we come to ISO, our third exposure control. This is a measure of the sensitivity of your camera’s digital sensor to light.
Making it more sensitive to light increases exposure, but it can also raise the noise level in your photos .
And the opposite is totally valid, decreasing the RISK decreases the sensitivity of the sensor as well as the noise level.
Here are the common ISO values in 1 Stop increments:
As you can see from the chart above, the ability to change THIS is quite limited.
Whereas there are 18 stops within the common shutter speed range, at ISO there are only seven
Today on the market there are cameras that manage to have an ISO adjustment at astronomical levels, such as ISO 12,800, 25,600 or even higher.
However, most of them end up bringing a lot of noise to the photos, especially at adjustments above ISO 3,800.
Anyway now all the settings speak the same league, STOPS, so it’s much easier to translate for each setting what you need.
It is different from the opening, understanding the adjustment of the ISO in stops is much simpler, so if I have ISO 100 and I want to raise a Stop, just set it to ISO 200, and so on.
Moment of truth, put it all together
Now that you are familiar with the Stop concept for each exposure adjustment, how about everyone together.
Now that we have covered the concept of stops for each of the three exposure controls, we are ready to talk about them together.
The key to understand here is that 1 Stop, is 1 Stop and that’s it. It will equal the aperture, shutter speed or ISO.
That said, raising a Stop at shutter speed is the same as opening the aperture at 1 stop, which in turn is the same as raising the ISO by 1 Stop.
But why is knowing what a stop in photography is so important?
Well the answer is simple, for absolutely every time you are going to shoot you will have to adjust your camera. And knowing this simple rule will give you more control over your exposure.
A beautiful example:
You want to increase the depth of field, and for this you know you need a smaller aperture. Only by choosing a narrower 2 Stops aperture, your image will be underexposed.
Using the Stop concept, just go to the shutter setting and allow more light to enter, that is, decrease the speed by 2 Stops, and you’re done. Only now your image is blurred, due to the very slow shutter.
Then, you can return the shutter to the setting it was in and use a 2 Stops setting on the ISO to solve the problem, or even set 1 Stop on each one, shutter and ISO.
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