What is Exposure? | Photography Definition, Tips, and Examples

This is a guide covering exposure.

In this glossary definition you’ll learn about:

No matter the number of years you have in photography under your belt, you must understand exposure.

Time to finally “shed light” onto the topic.

Let’s dive in.


What is Exposure?

The exposure definition in photography is quite straightforward, it’s the amount of light that enters your camera sensor or film if you’re using an SLR. To harshly oversimplify, it’s how bright your photo can be.

Photo by Leah Kelley

What Does Exposure Affect in Photography?

The exposure definition in photography is quite straightforward, it’s the amount of light that enters your camera sensor or film if you’re using an SLR. To harshly oversimplify, it’s how bright your photo can be.

Exposure is controlled by the three main pillars; aperture, shutter speed, and camera ISO. This may sound quite basic, but these pillars go a long way. Don’t forget that post-processing applications can also help increase/reduce exposure.

Does this topic bother professional photographers? Yes! Since every situation, scene, theme, and everything in between demands them to change their settings.

Achieving the proper exposure and mastering exposure will never be an easy feat. Simply achieving the right exposure doesn’t mean you have mastered exposure.

They should be perfectly balanced, as all things should be.

Got the sharpness but messed up the shutter speed? Try again!
Found the optimal shutter speed and ISO, but everything is still blurry? Try again!

You need the three settings to be just right. You need the correct depth of field, enough sharpness, nothing too much or too less.

To better understand the exposure meaning, it will be wise to understand what shutter speed, aperture, and camera ISO do. To support your knowledge, you will also need daily practice. Getting up and starting to lay out the foundations.

What is Photography Exposure Metering?

Exposure metering is essentially analyzing how properly lit an environment is. You can more accurately measure the exposure of a shot by buying the equipment yourself.

Unfortunately, the item can cost you as much as a DSLR would. The gadget is expensive and your camera already has its built-in metering modes. There’s nothing wrong with using what you have right?

These are the three common metering modes along with their respective use:

1. Matrix/Evaluative Metering

This metering mode is best to be used when your shot is well lit. It divides your LCD screen into several areas to count its exposure and proceeds to average it out. But, the center/focus area will take higher priority than the sides.

2. Center-Weighted Metering

There will definitely be times where the environment is against you, providing a difficult exposure situation. This is when you want to use the Center-weighted Metering.

As the name implies, this metering will only focus on the center of the frame. It will simply not care for everything outside the center, completely blurring it out.

This metering mode will give your subject the proper exposure while giving them a creamy background. A beloved mode especially fitting for portrait photographers.

3. Spot Metering

This mode will come in really handy when you’re in a tough “spot.”

As the name suggests, this mode only focuses on a little circle (size depends on each camera). Everything outside of it becomes irrelevant, like a tunnel vision.

It will meticulously calculate the exposure for that one small focus point. This mode is very useful when taking shots of small objects such as birds, leaves, flowers, frogs, etc.

exposure water
Photo by Ryan Stone

What are the 3 Components of Exposure?

In this section, we’ll talk about the three main components of the exposure triangle. Let’s start with shutter speed, aperture and end it with ISO.

1. Shutter Speed

In a nutshell, it’s the time your camera needs to take a photo. This ranges from 30 seconds, 10 seconds, 1/10 of a second, 1/15, 1/500 up to 1/1000-1/4000 depending on the camera.

While some cameras allow you to measure shutter speed in fractions, some models allow you to measure in full seconds too.

High-end camera models (Nikon D5, Fuji X-T2, etc) can even shoot at speeds of 1/8000 per second. But does this all really matter?

Well, there are two reasons: exposure and motion blur.


Speed matters. Shutter speed controls the amount of light entering the sensor, thus controlling the brightness.

Fast shutter speeds only let in a small amount of light, making your photo appear darker. If you don’t believe me, you are more than welcome to shoot on a hot sunny day. Your images would become overexposed as if you just looked into the sun.

On the flip side, a slower shutter speed will make the photo appear brighter. This makes it perfect for low-light photography at night.

Motion Blur

About motion blur, ever seen a picture of a waterfall so clear you could see its individual droplets?

Those types of photos will use a fast shutter speed. It makes high-speed subjects appear more clearly especially when using a 1/4000 shutter speed. As a comparison, your usual portrait would only need a 1/250 or 1/50.

While longer/slower shutter speeds emit motion blur, it still has its own use. It shows movement, the longer it gets, the smoother/lush the picture will become.

Don’t forget to bring a tripod, since it helps to prevent motion blurs.

2. Aperture

The aperture is basically the pupil of the camera, it also controls the amount of light that can enter the sensor. It changes the amount of light by using its aperture blades.

Aperture is counted as fractions. This system makes the f/1.4 larger than the f/22.

Larger apertures will always focus towards the foreground. This allows photographers to take extremely sharp photos up close while making the background appear blurry.

Larger apertures also allow more light to come in, making your photo brighter.

Smaller apertures behave in an opposite manner. They allow a minimal amount of light, making images look darker than they’re supposed to be.

However, smaller apertures produce a sharp image all the way from the foreground to the background. The thorough sharpness of the aperture makes it a staple for landscape photographers.

3. ISO

ISO is sometimes left out since it blatantly makes the image brighter. It directly makes the resulting image brighter and doesn’t affect incoming light, unlike the former settings.

But it may also become your only saving grace. More often than not, your only choice to capture an amazing photo after adjusting aperture and shutter speed is to bump the ISO up.

ISO mainly scales from 100, 200, and 400 up to 6400. Some cameras do possess the ability to go beyond the number, reaching a ridiculous ISO 25.600.

The higher you set the ISO, the brighter and noisier it becomes.

Noise is the “grainy” look that often appears on images with high ISO. But hey, a noisy image is still better than absolute darkness.

exposure sun
Photo by Joep Cox

What is Normal Exposure?

Normal exposure means the right combination of aperture, shutter speed, and ISO.

You should think of the game of finding the right combination of the exposure triangle by imagining moments when you fill a glass.

Take your aperture as to how fast the waters flow. Shutter speed is the time needed to fill it up. Finally, the ISO can be seen as the size of your glass.

Normal exposure also refers to your image not being under/overexposed by accident. The easiest way to check for this is by checking your histogram.

This may sound like a lot of work, but you just need to understand the basics when interpreting the histogram. In a nutshell:

  • If the graph doesn’t reach the highlights area, your image is likely underexposed.
  • If there is a spike at the highlights area, your image is probably overexposed.

Your job is to make sure that your image and main subject is properly exposed.

To improve the photo even better, consider shooting your images in RAW. The post-processing apps (such as Adobe Camera Raw) may be able to help you achieve a better image.

exposure cliff
Photo by Thom Holmes

What’s the Difference Between ISO and Exposure?

This is a good question.

The exposure definition translates to the amount of light that can hit the camera’s sensor. The amount of this light can be manipulated by changing your aperture and shutter speed.

On the other hand, ISO doesn’t really count as exposure. It doesn’t fit the description and it just works differently. While exposure can be manipulated by affecting the lens that captures the light, ISO just increases the brightness.

Let’s say you already have an image, you already finished adjusting the aperture and shutter speed but still can’t reach a good exposure. This is exactly when you want to involve your ISO.

The base ISO usually sits around 100, while you can pump it over 6400. This gives you plenty of room to brighten up your picture. The brightness is then increased based on the preview on the LCD screen.

The ISO method introduces noise while changing the exposure doesn’t add noise.

How Do I Get Perfect Exposure?

Yes, you can get a perfect exposure for that instance. The problem is, you will still need to change it every now and then for each photo.

Every scene, every subject, every theme will need different aperture and shutter speed settings. With this being said, I can’t give you a cheat sheet that guarantees a perfect exposure.

However, I can give you some recommendations to start off with. As someone who felt the pressure and confusion while starting out as a photographer, I know your troubles.

We just don’t know where to start. To sort this out, I prepared several general points where you can start at, before eventually mastering the exposures.

Landscape Photography

As you may know, landscape photographers need to adapt their settings based on nature itself. Here is the general guideline when taking photos:

  • Tripods become extremely important since you need to avoid blur.
  • Use the Aperture-priority mode. This mode allows you to manually select an aperture, while the shutter speed gets adjusted for you.
  • In general, you would like to shoot on f/8. But using smaller f-stops are also welcome if you’re aiming for a photo with more depth.
  • Don’t forget to adjust your ISO to its base value
  • Since you’re using aperture-priority mode, choosing the shutter speed shouldn’t be a problem. As long as the exposure is proper, all is well.
  • Be careful not to overexpose your image. In some situations, it would be much better to use negative exposure compensation on an image. Negative exposure compensation images are easier to fix in post-processing than overexposed images.

Portrait Photography

Since portrait photography is more focused on the client, less attention is given to the background.

  • You should shoot however you feel most comfortable with. Limiting your options will do more harm than good in portrait photography.
  • Choose the aperture-priority mode.
  • Opt for larger apertures such as f/1.4, f/2, or f/2.8 that gives the spotlight to your client.
  • Quickly change your shutter speed into something faster when you start encountering motion blur.
  • Don’t be afraid to use your ISO if the situation calls for it.
  • As with the previous recommendation, it’s better to use negative exposure compensation than having an overexposed photo.
  • Those two should be enough as reference points for your future settings. I also encourage you to start using manual mode after you understand how exposure works.
  • There are no universally used settings. So have fun and experiment with different settings for every occasion you come across.
@nate.joaquin on Instagram

Final Remarks

To recap this article:

  • Exposure is affected by aperture and shutter speed. ISO is not considered exposure since it directly increases brightness.
  • Photography exposure metering can help you calibrate the exposure of your shot. Each mode is made for specific situations and different focus points.
  • Normal exposure is considered when an image isn’t overexposed or underexposed. You can briefly check your histogram to confirm its exposure.
  • There is no such thing as the perfect-for-every-shot exposure. Each shot brings its own challenges. But the guideline and knowledge in this article should be enough to help you get started.

The process of mastering exposure is more of a trial and error process. The deeper you know how each setting affects one another, the better your exposures should be. The key is to simply keep practicing and studying.

Good luck!

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