The post The Exposure Lock Button: What Is It and How Do You Use It? appeared first on Digital Photography School. It was authored by Simon Ringsmuth.

Nestled quietly on the back of most cameras is a button that is often ignored or misunderstood, particularly by those who have recently upgraded to a DSLR or mirrorless camera. I’m talking about the exposure lock button, which can be a tremendous asset for photographers who are looking for ways to get more control over their cameras (and their photography in general).

But what actually is the exposure lock button? What does it do? And what makes it so helpful for photographers?

In this article, I share all the details – so that, by the time you’re finished reading, you’ll know exactly how to take advantage of exposure lock.

Let’s dive right in!

What is the exposure lock button?

Using the exposure lock button helped me get the correct exposure for this picture of two students studying for final exams.

To understand what this button does, it’s helpful to know a bit about how your camera calculates the exposure using aperture, shutter speed, and ISO.

In Full Automatic mode, these settings are all handled by the camera itself. The resulting images are often pretty nice but can sometimes turn out too dark, too bright, or otherwise not exactly how you intended.

In Manual mode, you are required to set all three parameters yourself. (This can seem intimidating at first, but is quite easy once you get the hang of it.)

However, if you shoot in one of the semi-automatic modes like Aperture Priority, Shutter Priority, or Program, you have a high degree of control, but your camera figures out a few things, too.

In Aperture Priority, you set the aperture and ISO, while your camera figures out the shutter speed to use for a properly exposed photo. And in Shutter Priority, you set the shutter speed and ISO while your camera sets the aperture. In these so-called “creative” modes, the automatic parameters (i.e., the settings handled by your camera, not you) are constantly changing depending on where you point your camera. Your camera analyzes the scene, then adjusts its automatic parameters in order to get a nice, even overall exposure.

This is where the exposure lock button comes in. When pressed, exposure lock freezes the exposure parameters set by your camera until you take a picture. In other words, it locks your camera into its current exposure settings, and only releases it once the image has been captured.

You might be wondering: What’s the use in that? Isn’t it good to have your camera change its parameters to fit the scene?

Not quite. Exposure lock can be handy in a variety of scenarios. It’ll all make more sense when you understand how it can be used:

Why is exposure lock useful?

I didn’t have much time to get this shot, so using the exposure lock button was a quick way for me to get the image I was looking for.

I shot the picture below in Aperture Priority. I set the aperture to f/2.8, while my camera selected a shutter speed of 1/500s. Unfortunately, my camera was looking at the entire scene, not just the subject, and chose a shutter speed that resulted in my subject being far too dark. The tradeoff was that the background was properly exposed, but my camera did not know that I was more concerned with the teddy bear than the scenery outside!

I shot this in Aperture Priority at f/2.8. Because of the bright light through the window, my camera picked a shutter speed of 1/500s. The outside looks great, but my subject is horribly underexposed.

To correct the problem, I simply pointed my camera down at a darker spot in the foreground and let my camera select its shutter speed once more. (I kept the aperture at f/2.8.) Once the camera had chosen a shutter speed to correctly expose the foreground, I pressed the exposure lock button, and I held it down while recomposing my shot to match the original framing.

My camera selected a slower shutter speed of 1/30s, which I locked in. This resulted in my subject being well lit even though the background elements were a bit too bright:

By pointing my camera down, locking the exposure, and then recomposing, I was able to capture an image at f/2.8 with a shutter speed of 1/30s. The shutter speed was far too slow for the background to be properly exposed, but my subject looks just fine.

You might look at my photo and wonder where the background went, but remember what happened in the original when the background was visible: the subject was too dark. By locking the exposure such that my subject was well exposed, the background ended up far too bright. It worked out just how I wanted because it was the bear that mattered to me and not the scenery outside the window.

I could have also employed another method to get my subject properly exposed, such as center-weighted metering or adjusting my camera’s exposure compensation, but in this case, I found the exposure lock function to be quick, plus it made it easy enough to get the job done. It’s a handy tool to have in your back pocket for those times when you need to quickly over- or underexpose your shot because your camera isn’t giving you the results you want.

The Exposure Lock button came in handy here as well; it helped me get a background and a foreground that are well lit.

How to work with the exposure lock button on your camera

If you’re interested in trying your hand at exposure lock, most camera manufacturers make it fairly painless. 

On Nikon cameras, you’ll often find a button that reads “AE-L/AF-L” and is located about an inch from the right-hand side of the camera (on the back):

Most Nikon bodies have the exposure lock button in the top-right corner, but the exact location on your camera may be a bit different.

Canon’s button tends to be a bit smaller and marked with an asterisk:

On this Canon DSLR, the exposure lock button is in the upper right-hand corner (to the right of the AF-ON button). If you look carefully, you can see a hint of an asterisk on the top of the body.

Sony, Pentax, Olympus, and others have this button, too, but its exact appearance and location varies depending on the manufacturer and model.

Also bear in mind that the functionality of the exposure lock button changes depending on your camera (and depending on your camera settings). On some cameras, you must hold down the exposure lock button until you take the photo; on others, giving the button a single press will lock the exposure until you take a photo.

If you’re unsure about your own camera’s exposure lock feature, I encourage you to take a quick look at the manual (or do a few hands-on tests!).

Use exposure lock to your advantage!

The exposure lock button is a nice tool to have at your disposal, but it’s not quite the same as shooting in Manual mode while reading your light meter and histogram to make sure your exposure is nailed precisely how you want it. Still, it’s a fantastic way to adjust your exposure quickly without changing any metering modes or other shooting parameters. I often find myself using it when I need to over- or underexpose the scene in a pinch. Once you get the hang of it, you might find yourself using it in a similar fashion.

So give exposure lock a try. Figure out where the button is located on your camera, then spend a few minutes taking photos while locking the exposure. Though it’s not useful in every scenario, it can certainly help, so it’s a good function to understand.

Now over to you:

Are you a fan of the exposure lock button, or do you have any other photography tips to help your curious camera-owning counterparts get photos that are properly exposed? Leave your thoughts in the comment section below!

The post The Exposure Lock Button: What Is It and How Do You Use It? appeared first on Digital Photography School. It was authored by Simon Ringsmuth.