I remember the first time I picked up a camera. I was excited, for sure, but after the excitement came a bit of panic.
I had no idea whatsoever how to use that thing, and with all the buttons, modes, and dials on it, I figured it would be a good, long while until I knew what I was doing.
I started with the "big boys" first - learning the camera modes, how to control aperture, shutter speed, and ISO, and finding my way through white balance and metering modes.
But one thing that I neglected to learn until much later on was how to use my camera's AF, AE, and FE lock functions.
In the spirit of helping you avoid the same mistake, let's explore these three lock functions and see what they can do to help you improve your photos.
What is AF Lock?
For starters, AF stands for autofocus, so the AF Lock function locks the autofocus on its current focus point.
This is a handy feature to use when you need to focus the shot and then recompose.
For example, let's say you're taking the portrait shown above, and the active AF point is the one in the middle of the viewfinder.
Instead of simply composing the shot with the subject in the middle, you can get the shot focused, hold down the AF Lock button to lock the focus, and then recompose the shot as seen above, with the subject shifted to the right of center.
See the value of doing so in the video below by Matt Granger:
AF lock can be engaged in other ways, too.
Perhaps the easiest and most-used method of locking focus is to depress the shutter button halfway.
Just like in the example above, that allows the camera to acquire focus, lock it in place, and gives you the ability to recompose the shot as you wish.
The problem that some photographers run into with this AF Lock method, though, is accidentally pressing the shutter all the way down, resulting in an unwanted photo.
To get around that problem, you can use what's called back-button focusing.
Back-button focusing is just what it sounds like - you assign AF Lock to a button on the back of the camera.
That means that the shutter button is responsible for one thing - firing the shutter - and focus locking is transferred to the button you've selected on the back of the camera body, like the Fn2, Fn3, or Fn4 buttons shown on the camera above.
Whichever way you choose to do it - via the AF Lock button, depressing the shutter button halfway, or using back-button focusing - locking the focus before you take a shot will not only get you images that are sharply in focus, but it also gives you more creative freedom regarding how those images are composed.
Learn More:
What is AE Lock?
The acronym AE stands for automatic exposure. Naturally, the AE Lock button allows you to set the exposure settings - aperture, shutter speed, and ISO - and lock them into place.
The question is, why would you want to lock the exposure settings?
One of the most common applications for using AE Lock is when you're taking multiple images that will be stitched together, like in a panorama like the one seen above.
In that situation, each image needs to have the exact same exposure, that way there's no weird darkness or brightness issues from one image to the next.
To do that, you simply dial in the appropriate exposure settings for the first shot in the sequence, engage AE Lock, and you can take the rest of the photos in the panorama with the confidence that each one will be exposed in the same manner.
AE Lock can also be useful in situations in which there is dim lighting.
Again, once you dial in the appropriate settings to get a well-exposed image, using AE Lock means you won't have to continuously adjust the exposure settings as you shoot in low light.
Of course, this works great assuming that the lighting conditions stay relatively constant as you're shooting. But if changes occur - it gets darker, for example - the exposure settings you've locked in will result in images that are too dark because they were locked in when there was more light available.
As a result, bank on AE Lock only being good for a few shots at a time. However, even if you can only get 2-3 shots, it's worth it to use AE Lock.
But perhaps the best application of AE Lock is quite similar to AF Lock.
As mentioned above, you can use AF Lock to lock the focus so you can recompose the shot as you wish.
AE Lock does the same thing, only it allows you to lock the exposure settings and then recompose the shot.
All you have to do is frame up the shot to get a meter reading off the subject, engage AE Lock, recompose the shot, and then fire the shutter.
Doing so allows you to maintain the initial meter readings, even if the act of recomposing the shot changes the exposure.
See AE Lock in action on a Canon camera in the video above by CanonUSA.
Learn More:
- Four Tips from the Pros for Getting More Out of Your Camera
- A Beginner's Step-by-Step Guide to Understanding Metering Modes