Exposure

Exposure in photography is the cornerstone of capturing the essence of a moment, intertwining light, and time to paint with pixels and film...

What is exposure in photography?

Exposure is the amount of light that reaches your camera’s sensor through the lens which then affects how bright or dark your image turns out. Our goal as photographers is to take images that are well-exposed.

Importance of exposure

If your images aren’t properly exposed, then they will either be underexposed or overexposed.

Underexposure vs. overexposure

If your image is too underexposed then it will be dark, and if your image is too overexposed then the highlights will be blown out and your image may look faded. For example, here's an image I took making it underexposed and then overexposed:

Often, you may see images that are purposely underexposed or overexposed to create an artistic effect, which is popular on social media. In fact, I used to purposely underexpose my images just a little bit and post them on Instagram to create that moody look that is popular:

This is fine to do if you are intentionally doing it and you are doing it solely for your own creative purposes. But if you photograph clients like I do and you will be delivering photos to them, then it’s best that you capture a well-exposed photo because your client may not like the artistic effect you were trying to achieve.

Now, in order to understand the concept of exposure, you need to understand the exposure triangle.

What is the exposure triangle?

The exposure triangle is made up of three different settings that affect the overall exposure of your image – aperture, shutter speed, and ISO. All three of these elements act like three cogs in a wheel; if you adjust one, then the other two will will be affected.

For example, let’s say you’re taking a picture of a really fast subject like a car. In order to freeze frame the car you will need to use a very fast shutter speed, but this will let less light into your camera sensor.

In order to balance out the exposure, you will need to use a wider aperture (lower f-stop number) and a higher ISO. That’s just one example of how changing one setting will affect the other two. Let’s look at all three settings individually to get a better understanding while using that analogy.

Aperture

Aperture, specifically the aperture blades in your lens, can open or shrink which affects the amount of light that passes through the lens, affecting the overall exposure of your image.

Depending on you aperture setting, your aperture blades will either shrink letting less light pass through or widen letting more light pass through.

The lower the f-stop number (ex. f/1.8), the wider the aperture (more light), and the more shallow depth of field (background blur). For example, here's an image I took using f/1.8 for a shallow depth of field:

The higher the f-stop number (ex. f/16), the more narrow the aperture (less light), and the more narrow depth of field (everything in scene is in focus).

For example, as a portrait and headshot photographer, I’m often using lower f-stop numbers so I can have more shallow depths of field, creating that bokeh, background blur effect behind my subjects. Here's an aperture/f-stop chart for you to reference to better understand:

Shutter speed

Shutter speed is the amount of time your camera’s shutter is open which affects how long light can hit the sensor.

Shutter speeds are measured in fractions of a second such as 1/250 or 1/1000 of a second.

One reason to control shutter speed is that it allows you to let more or less light into your camera sensor depending on the time of day and light availability.

If there’s less light in your scene such as during sunset or at night, you’ll likely use a slower shutter speed to let more light in. If there’s a lot of light in your scene, like during midday, you’ll likely use a faster shutter speed to let less light in.

Another reason to control shutter speed is for motion effect, when you want to intentionally capture a motion blur image or a fast freeze frame shot. If you want to purposely capture motion blur, you’ll likely use a slower shutter speed.

For example, many long exposure photographers keep their shutters open for minutes or even hours (using a tripod of course).

If you want to capture a freeze frame effect of a fast subject, you’ll likely use a faster shutter speed like 1/1000 of a second.

As a portrait photographer myself, I often try not to go below 1/150 of a second because I’ve found that if I go lower, I can introduce some camera shake and blur into the image because of how I shoot handheld.

ISO

ISO is the sensitivity of your camera’s sensor to light.

ISO’s are measured in flat numbers such as ISO 400, ISO 1600, etc.

Higher ISO numbers means your sensor is more sensitive to light which will make your image more exposed if not balanced properly. Higher ISO numbers can also introduce digital noise, making your image look grainy so that’s something to watch out for.

Because of this, you’ll want to know the ISO level your camera can handle before it starts introducing significant digital noise and try to stay under that level if you can. Here's a very high ISO image taken at ISO 16000. Notice the noise:

Here's a lower ISO image taken at ISO 2000. Notice it's less noisy:

Lower ISO numbers mean your sensor is less sensitive to light, which will make your image less exposed if not balanced properly. I usually adjust my ISO last out of all three settings, especially if I am getting close to the limits where grain and digital noise will start to be introduced.

Sometimes, you have no choice but to have noise in your image, and it’s easy, especially now, to remove it in post-processing, but I found that having it noise-free straight out of the camera always looks better.

So knowing when to adjust each of the three settings is just dependent on remembering what each setting is primarily used for.

Just remember:

• Aperture affects depth of field
• Shutter speed affects creating a motion blur or freeze frame effect
• ISO is raised higher when you are satisfied with the depth of field and motion effects achieved by your aperture and shutter speed settings but still need to adjust the exposure.

We’ve discussed the three settings that affect exposure, now let’s put it all together and go over all the steps and tips I recommend using when you want to achieve the right exposure.

How to get the correct exposure?

There are 7 steps you need to follow and be aware of to get the right exposure in any scene.

1. Understand the exposure triangle

The first step is to understand the exposure triangle. We covered it earlier, but take the time to fully understand each setting – aperture, shutter speed, and ISO so that you can quickly adjust your settings on the spot on photoshoots.

2. Use the right metering mode

The second step is to use the right metering mode. Cameras offer different metering modes such as evaluative, center-weighted, and spot metering that allow you to measure the brightness of the scene.

You’ll want to be familiar with these different metering modes and then select the one best suited for your photography purposes. For example, I mostly photograph portraits and headshots so I like using spot metering.

3. Shoot in manual mode

The third step is to shoot in manual mode. Manual mode will allow you to have full control over your aperture, shutter speed, and ISO settings.

4. Start with aperture and shutter speed

Once you’re in your photoshoot location, I’d recommend starting first with aperture and shutter speed. This will allow you to dial in your desired depth of field and motion effect goals.

5. Adjust ISO as needed

After you are satisfied with your aperture and shutter speed, adjust your ISO settings to make them higher if you still need more exposure in your image.

6. Check exposure meter

Once your settings are dialed in, put your eye in the viewfinder and get ready to take a photo and look at your exposure meter which is usually on the bottom. This is the meter that shows a scale running from -3 to +3, with the “0” in the middle representing what the camera believes to be the correct exposure.

For example, in my exposure meter here, you can see the photo is underexposed at -2.

By looking at this line and marker, you’ll get a good idea whether your photo is properly exposed or not. If it’s overexposed or underexposed, then make the proper adjustments to your aperture, shutter speed, or ISO. If you're shooting in an automatic exposure setting, then you can use exposure compensation.

7. Check the histogram

Lastly, if you really want to check whether your image is properly exposed, look at the histogram within your camera. You can usually access the histogram using the playback function of your camera. Please check your specific camera settings, but I can access my histogram by clicking “Info” while an image is being played back.

The histogram shows a distribution of brightness levels in your image from the blacks on the left to the whites of the right.

If your image is well-exposed, then the image will typically be balanced spread across the histogram without big spikes on either end:

Here's an example of that same scene underexposed. You can see this with a shift to the left (shadows and blacks):

Personally, I don’t always check the histogram after each image I took especially if I’m on a client shoot because this would be terrible for the client experience. I usually just set my settings based on experience and then just confirm that it’s properly exposed by looking at the exposure meter and by doing a visual check in the playback area!

In conclusion, the best way to understand and get the proper exposure is just by practicing. The process of mastering exposure is more of a trial and error process, but it is one you must take the time to learn on your journey of learning photography.

Take photos in different lighting conditions with subjects moving at different speeds. Play around with aperture, shutter speed, and ISO to see how it affects your images. After a while, you’ll become more experienced and know right off the bat the ballpark range that your exposure settings should be at based on your current lighting.

Good luck, and have fun!