What Is F-Stop? Definition & Best Practices in Photography

As a beginner, you may feel discouraged by the technical terminologies you came across. Don't.

These technicalities are easy to understand and will boost your performance as a filmmaker or photographer.

Today we will be addressing one of the numbers of your viewfinder: The f-stop.

Before you start learning about f-stop, you should know all of the basics of photography. Read our article to learn everything you need to know.

What is f-stop?

F-stop is the number you see changing as you adjust the size of your aperture. In theory, it is the ratio between the lens, focal length and the aperture circle diameter. Consequently, it will affect the focus and exposure of your image. If you prefer to simplify, you can look at F-stops as units of measurement that let you know the size of the aperture. The f-stop will appear in your screen/viewfinder as f/number, like f/1.2, f/8, f/32, etc.

Aperture and f-stop

Aperture, ISO and shutter speed are the elements that constitute the exposure triangle. In other words, they work together to produce a properly exposed image. Aperture and f-stop are two very close concepts and are often used interchangeably.

Aperture is the lens pupil diameter through which light enters, while f-stop is about how much light you allow to hit the sensor via such aperture opening. Since f-stop = focal length/diameter, smaller f-stop numbers (1, 2, 3, and 4) translate into a larger aperture.

Most common f-stop values

• f/1.2
• f/2.8
• f/4
• f/8
• f/11
• f/32

The f-stop aperture scale

The F-stop scale helps you to measure and understand the aperture size. Consequently, it guides you in terms of exposure and focus. In this numerical list, each step down allows half as much light to enter:

• f/1.4 (very large opening of your aperture blades, lets in a lot of light, shallow depth of field)
• f/2.0 (lets in half as much light as f/1.4)
• f/2.8 (lets in half as much light as f/2.0)
• f/4.0 (lets in half as much light as f/2.8)
• f/5.6 (and so on)
• f/8.0
• f/11.0
• f/16.0
• f/22.0
• f/32.0 (very small aperture, lets in almost no light, deep depth of field)

f/1.2-f/2.8

Larger apertures allow more light in, making them advantageous in low-light situations. The shallow depth of focus makes the subjects stand out while the backdrop gets blurred. F-stops in this range are also often utilized in portrait photography.

f/4-f/8

These apertures offer a great middle ground. The depth of field is not as shallow (allowing more items to be in focus at varying distances), and there is still enough light. Besides, it usually allows more contrast.

f/11-f/32

At f/11 and higher, you obtain a wide depth of field, meaning that nearly everything in your frame is in focus. If you want to capture subjects at various distances, increase your aperture to ensure nothing is missed. Unfortunately, it also means sacrificing the amount of exposure. This range is perfect for scenes with a lot of light and landscapes.

What effects do f-stops have on an image

F-stops will determine the amount of light and the amount of clarity or blur present (the depth of field).

The bigger your f-number (narrower aperture), the greater the depth of field. When capturing a landscape, for example, having a higher depth of field is advantageous since we want to incorporate a large area with many elements on the horizon.

When we only want to isolate one subject in a photo (such as in a portrait), we utilize a shallow depth of field to make that subject stand out from its surroundings and backdrop.

Moreover, a lens with a larger maximum aperture allows more light to enter the camera, which has many benefits. Since the aperture is only one of the elements of the exposure triangle, increasing the light entrance through it means you will be able to play around with the other two elements. In other words, it concedes you to shoot with a faster shutter speed and lower ISO for any given lighting scenario.

Go into depths with the aperture

By the end of this, it is safe to say that you understand f-stops. Yet, it does not end here. To master exposure and focus, complement your knowledge by learning more about aperture. Go into depths with aperture.

F-stop FAQ

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