Whether you are using an entry-level DSLR like Nikon D3100 or a top of the line DSLR like Nikon D3x, there is a special button on the back of your camera labeled “AE-L / AF-L” that can be quite useful in many situations. After I wrote the Autofocus Modes article, I received several requests from our readers, asking me to explain what the AE-L / AF-L button does, when it should be used and how it can be combined with different autofocus modes. In this article, I will try to go through this button in depth and explain how I personally use it on my cameras.
1) AutoExposure-Lock / AutoFocus-Lock
The AE-L / AF-L button stands for “AutoExposure-Lock and AutoFocus-Lock” and its primary function is to lock camera exposure and/or focus. What does this exactly mean? If you are using any of the camera modes like Program, Aperture Priority, Shutter Priority or other scene modes, the button could be used to force the camera to use a certain value for shutter speed, aperture, ISO and white balance. Since in any of the automatic modes the camera uses its metering sensor to determine the optimal exposure, instead of having your camera re-evaluate the light every time you recompose, you could lock the exposure to a value you are comfortable with – hence the term “AutoExposure-Lock”. There are many cases where using this feature is very helpful. One example is when you photograph panoramas. It is extremely important to use exactly the same exposure from frame to frame in panoramic photography. If one exposure differs from another, it is practically impossible for panoramic software to stitch images together in a consistent, continuous form. Another good example is if you are photographing a subject with a constantly changing background and you want to expose the subject exactly the same way from shot to shot. Basically, any time consistency of exposure is required and you do not want to switch to a full manual mode, the AE-L button can be very useful.
What about AutoFocus-Lock (AF-L)? Similar to exposure lock, autofocus lock can be used to stop the camera from making the lens reacquire focus when you recompose. For example, if you are photographing indoors in dim environment, you will find that using the center focus point is going to give you the most accurate results. This is because the center focus point is always the most accurate, especially on entry-level DSLRs that only have one cross-type sensor. So if you want to use the center focus point to acquire focus, it does not always mean that you want to position your subject in the center. As soon as you recompose your shot and half-press the shutter button again, the camera will be forced to reacquire focus. If you shoot in “AF-S” or “Single Area Focus Mode“, you could continue half-pressing the shutter button without releasing it when recomposing your shot, which would not force the camera to reacquire focus. However, if the camera is set to “AF-C” or “Continuous Focus Mode”, then the camera will always continuously reacquire focus when you half-press the shutter button and recompose your shot. So if you do not want to deal with these situations, you could use the AutoFocus-Lock feature of the camera to lock the focus on your subject, then you could recompose the shot and take a picture. The focus will remain on your subject and will not change, as long as you continue to hold the button. Please note that you have to be careful when recomposing shots like this, because the focus plane that is parallel to camera sensor changes, which will often result in bad focus when using large apertures.
2) Default AE-L / AF-L Behavior
The default behavior of the AE-L / AF-L button is typically set to lock both camera exposure and focus. Entry-level DSLRs typically have a limited control over this button’s functionality, while pro-level DSLRs have many ways to control the behavior of the AE-L / AF-L button. For example, the Nikon D3100 only has 5 options for this button: AF / AE lock, AE lock only, AF lock only, AE lock (hold) and AF-ON (see more on these below), while Nikon D300s has all of these, plus 12 more ways to control the button’s behavior. So the number of ways to customize the AE-L / AF-L button will depend on the camera model.
3) Types of AutoExposure and AutoFocus Lock Modes
You might be confused when you see the different types of AE and AF options in the camera menu. Which one does what and what should you set yours to? Let’s go over each one, but first, go to your camera menu and Navigate “Custom Setting Menu”->”Controls”->”Assign AE-L/AF-L button” (on D5000, D5100, D90, D7000, D300s, D700, D3s and D3x) or to “Setup Menu”->”Buttons” on D3100:
You should see some or all of the below:
- AE/AF lock – the default behavior of the AE-L/AF-L button. Will lock both camera exposure (shutter speed, aperture, ISO and white balance) and lens focus. The feature will only be active while you hold down the button. Once you release it, the lock will be released as well.
- AE lock only – will only lock the camera exposure, so focus will be reacquired if you recompose the shot. Also only works while you hold down the AE-L/AF-L button.
- AE lock (Reset on release) – exposure will be locked once you press the AE-L/AF-L button and will stay locked until you take a picture, even if you release it.
- AE lock (Hold) – exposure will be locked when the button is pressed and will stay locked even if you take multiple pictures. The lock will be automatically removed if the camera is inactive for a time period set in the “Auto meter-off delay” menu setting, or can be also removed by pressing the AE-L/AF-L button again.
- AF lock only – only focus will be locked while the button is depressed. The lock is removed as soon as you release the button.
Please note that when the AE-L / AF-L is depressed and the camera is set to any of the AE modes, you will see an “AE-L” indicator in your viewfinder. If you set it to “AF lock only”, the indicator will not light up.
You might also find many other options under “Assign AE-L/AF-L button” such as “FV Lock”, “Live View”, etc. I won’t go over these, since these options depend on your camera and will also change the functionality of the AE-L / AF-L button. The only option I will mention, is “AF-ON”, because it is a very useful feature on entry-level DSLRs like Nikon D3100 and D5100. Since entry-level DSLRs do not have a dedicated autofocus “AF-ON” button, you can set the AE-L / AF-L button to acquire focus instead (which will de-activate focus acquisition when you half-press the shutter release). That way, you can acquire focus with the AE-L / AF-L button and take pictures with the shutter release. Then, you don’t have to worry about locking your focus when you recompose, since half-pressing the shutter release button will do nothing.
So, which lock mode do I personally use and why? When I use an entry-level DSLR, I either choose “AE/AF lock”, so that both exposure and focus stay locked together, or I set the button to “AF-ON” and use manual mode to keep my exposure consistent. On higher end DSLRs with a dedicated “AF-ON” button, I always choose “AE lock (Hold)”, so that only the exposure is locked – the camera will not automatically reacquire focus when the “AF-ON” button is activated. I use this feature quite a bit when taking panoramic shots and I like the fact that the exposure stays locked while I take pictures. Once I am done, I either press the button again, or let the lock time out. Turning the camera off also releases the lock. Oh, and if you happen to change your camera mode from say Aperture Priority to Shutter Priority or to Program, the exposure values will stay locked.
4) Exposure lock and metering
You might wonder about how to properly meter your camera before even locking the exposure. If you are confused about metering, I highly recommend checking out my “understanding metering modes” article, where I go through different types of camera metering modes in detail. Determining the correct exposure is relatively easy nowadays with modern DSLRs, because cameras are equipped with complex metering systems that use various algorithms and preloaded templates to accurately set exposure values. On top of that, plenty of options to control and fine tune the exposure are provided to end users – different metering modes can control the way exposure is evaluated by the camera, while exposure compensation can be used to override the calculated exposure.
Let me give you an example on how you can combine camera modes, metering modes, autofocus modes and autoexposure lock to take a picture. Say I am photographing my son at sunset on a beach, with the sun behind him and me in front of him. I am in Aperture Priority mode, where I set the aperture and my camera automatically calculates the shutter speed. I normally use Matrix Metering” mode, so the camera most likely would expose the background correctly, while my son becomes a silhouette (because the background is much brighter):
So if I wanted to expose my son correctly without worrying about blowing out the background, I would switch to Spot Metering mode and position the focus point on his face. The camera would then meter off his face instead, exposing him properly and not paying attention to the background. If I take a picture and he is still underexposed, I would dial positive exposure compensation to further brighten him up or if he is overexposed, I would dial negative exposure compensation. Once my exposure looks good, I would press the “AE-L / AF-L” button on the camera (which is set to “AE lock hold”) to lock the exposure and continue taking pictures without worrying about setting the exposure again. If he constantly moves while I take pictures, I would pick Continuous Autofocus Mode (AF-C) to track his movement.
Remember, all these tools are given to us to simplify our photography, so that we can concentrate more on capturing great images, rather than worrying about properly calculating the exposure. Once you learn how to use these different modes and features, you will be able to capture images the way you want to with ease.
Hope you find the above article useful. Let me know if you have any questions!
About Nasim Mansurov
Good! I hope always to have a printable version of your good articles. Thanks
Thank you Giulio! Soon, very soon! :)
I found the button helpful when I am on wide angle and in the place where there are some bright lights on the ceiling. Then I am setting up my exposure without all these bright points lock it by AE-L and recompose the frame. The lights becomes overexposed and it looks great. It is also possible in manual mode.
Tomasz, that’s a good way to use the AE-L button for sure, since you are exposing for the subject instead of the bright lights. Thank you for your feedback!
Hi Nasim, great article. Why have you stop mentioning the D5000? Just because Nikon has released the D5100? :(
Thank you Eduardo! No way, I simply forgot ;-) I fixed the article.
Eventually, I will stop mentioning it though, since it is replaced by D5100 now.
right on time!!! i have been trying to figure out these buttons. I have read the manual but for some reason, I just don’t get it. :(…Thanks for the great explanation and for pointing out some examples, it’s really helpful!!!
Thank you for your feedback Noreen!
Interesting article about something I never paid attention to. I printed it and will study it.
However, I will compare two processes: (1) setting my camera to manual v. (2) AE-L/AF-L approach.
I’ll let you know how I come out.
Peter, sounds good! Both ways work great and I do use both when I shoot.
My conclusion: I will probably rely more on the the manual setting for things like panoramas where you have plenty of set-up time, use a tripod, etc.. But, as APW below said, the “lock” approach does offer real advantages when recomposing images and not shooting manual. I intend to use it that way.
I also discovered something else on my D300 and D700…it has an AF-ON button near the AE-L/AF-L button!!! Very clever these Nikon engineers. Now thatIi know it’s there,I may find a use for it.
Good article. Made me discover some new shooting opportunities.
Nice article and definitely worth writing about. I use the lock all the time when recomposing images.
Thank you for your feedback!
Thanks Nasim,
like always it’s a delight to read your articles..
You are most welcome Daya!
another great read… thank you for posting….
Hi Nasim, I just wanted to provide one clarifying comment on this:
“So if I wanted to expose my son correctly without worrying about blowing out the background, I would switch to Spot Metering mode and position the focus point on his face. The camera would then meter off his face instead, exposing him properly and not paying attention to the background. If I take a picture and he is still underexposed, I would dial positive exposure compensation to further brighten him up or if he is overexposed, I would dial negative exposure compensation. Once my exposure looks good, I would press the “AE-L / AF-L” button on the camera (which is set to “AE lock hold”) to lock the exposure and continue taking pictures without worrying about setting the exposure again.”
At least on D700, you can also first lock the spot metered exposure (with AE lock hold) and after that, when it is locked, tweak it with exposure compensation. I find it easier to operate that way.
Thank you for great and informative web site.
I want to buy a flash for my d90. What do you recommend?
My kids play indoor soccer and I do a lot of indoor shooting.
Thank You.
“As soon as you recompose your shot, the camera will see that the area the center focus point is on has changed and it will force the lens to reacquire focus on the new area”
I am slightly confused. I have a D90. I mostly shoot in AF-S mode and in that mode this doesn’t happen. I acquire focus by half pressing the shutter button. After the focus is acquired, it remains locked as long as the shutter button remains half pressed. If I rotate my camera with shutter button half pressed, focus is not acquired again. Is my understanding wrong?
excellent help and opinion,very useful will try and apply,thanks
this is very2 important in photo merging, you have to lock both exposure and focus :)
Great article! Thank you :0)
I always use back button focus on my d7000 , it was a bit tricky at first but once i got used to it i find it much easier to focus , would not go back .
I am also shooting with the d7000 …. where is the back button focus? Do you mean AF-On? And if you use AF-On, are you using it in AF-S or AF-C? Thanks.
What exactly means “to recompose”?!!!
Just say you want to take a photograph of two people standing side by side and lets say your camera is on a single centered focus point, if you aim directly two the centre point your camera may focus on the backround behind the subjects causing the backround to be in focus and not the two subjects.
So what you do is turn the camera to say one of the subjects faces like the one on the left and half press the shutter to focus and then you recompose the shot turn the camera right slightly so that both subjects are centered in the middle of the shot then continue to press the shutter fully.
Or basically you aim the focusing point of the camera on the subject and half press the shutter then adjust the composition to where you want it then fully compress the shutter. Also handy when you want your main subject to be in focus but is not or you don’t want it in the very centre of your photograph and maybe off to the side perhaps.
I am new to photography. So, the AF-L/AE-L is not useful when shooting in Manual mode. If so, what should I do to lock focus and exposure in manual mode
Thanks for taking the time to explain this feature. I was reading a book and they were talking about Back Button Focus and I thought, “That’s what I need…where is it.” They then explained that it can be different for each camera and make; what?
Did a search on the web for “Back Button Focus with D5100″ and there was your article. Very easy to understand and even gave me some additional things to think about. I’ve seen the AF-L, AE-L on my menu and didn’t have a clue.
Again, thanks for an excellent article that fully explained the terminology to me.
Hi Nasim
I recently happened across your website (while searching for reviews of the 24-120/4) and have enjoyed reading the articles on it. However this one reminds me of a problem I have had with my D5000. I tried using the AEL/AFL button as AF-ON, but even after activating focus using the AF-ON button, the camera will refuse to take a photo unless the active AF sensor is currently in focus. So if you recompose in a way which takes the active AF sensor off the subject (which is the whole point of using AF-ON anyway), the camera still will not take the photo since it thinks it is not in focus.
On higher end bodies one could overcome this by selecting “release priority” not “AF priority” mode. However as far as I can see, there is no setting for this on the D5000. What am I missing?
BTW I am very impressed how you respond to comments on your website. I know it mus take a lot of your time to help us with our problems. So thanks in advance!
Andrew
Really useful information for me as I still confuse how to use this button properly. Great thanks for that !
Thank you so much for this article. I’ve tried to explain to my partner so many times why I use the ae-l/af-l button without getting it across properly. I gave him your article & now he gets it!
Great article! I do have two points of confusion though, if you don’t mind. I use the AF-on exclusively for autofocus, (disabled on the shutter) use focus recompose in AF-S, aperture priority mode. When I meter off the active focal point, then depress the AF-on does this not lock the exposure? I’m confused why I’d use the AE lock as well.
” On higher end DSLRs with a dedicated “AF-ON” button, I always choose “AE lock (Hold)”, so that only the exposure is locked – the camera will not automatically reacquire focus when the “AF-ON” button is activated.”
It will though, otherwise how will you acquire focus? It wouln’t IF you had chosen AF lock too.
Lastly, in the example of photographing your son at sunset, you’ve stated that you’d dial in exposure compensation. Does this have the same result as manually overriding the settings to ISO to achieve the desired exposure, (if one is well versed in full manual exposure) or is there another benefit to this method?
Really appreciate your time and expertise!
For the sunset picture, you mention you are in aperture mode and then state that if he is still underexposed you would dial positive exposure compensation. Am I wrong in thinking that is impossible if you are in aperture mode? I’m new to this so if it is a stupid question, I apologize.
You can dial in +/- exposure compensation while shooting in Aperture. Look for the square button with the +/- signs. As far as I know, the only mode you can’t use the Exposure Compensation is Manual ….. this is because there is no need since you are “manually” setting everything. Hope this helps. :)
Jajajaja, pendejos, y eso l son mui mui listos mientras yo ni si kiera se escribir
Hi, Nasim. Came to your site to reserch for a certains problem in my D3000 Nikon AF-S DX Nikkor lens.
Suddently it lost the autofocus. It just focus manually.
I’m trying like that:
LENS: “A” mode
SETTINGS: AF-A, Auto-area, AF-assist On, Matrix metering. It simply doesnt shoot. Or when it shoots, it doesnt focus automatically.
I think the lens is broken…
Would it be?
Cheers from Rio de Janeiro!
Hi there, just got myself a Nikon D3100 and reading the book confuse the heck out of me. So I found your site.. Thank you… It is slowly starting to make sense now. Awesome jobs, thanks for making it simple for us.
This subject cannot be explained better than this………. Many thanks
Superb article, this is how it should be written in manuals so that it supports everyone from enthusiasts upwards. I agree with Faisal above, it could not be explained better. Nice job and thanks.
Hi Nasim!
Thank you for yet another great article that clarified things for me. I tried to read in my Nikon user manual about the auto focus and the use of the AE-L / AF-L, but it just left me confused. Your article made me understand how to use this button properly. Thank you for taking the time and effort to write articles like this, I really appreciate it.
Great article. Very informative.
I have bookmarked your site and is the primary source of my better understanding of photography.
Thanks a lot. keep up the god work.
This was concise, clear, and to the point. Thank you!!! I will be back to your site to learn more about how to make the most of my DSLR!
I am 71 years young and I have been taking photos for a long time (my first camera was a Leica III c) but I am just starting bird photography and of course with digital cámeras (D300s, D7000, 300 f4, 80-200 f2.8 and 70-300 VR).
About the AE-AF lock. Nikon D300s manual suggests NOT to AE lock if you are using matrix (it says something like you may not obtain the results you want) I am confused about this, could you comment on that.
If using center weight or spot, would it not be easier to activate the AE hold function in the shutter so you hold both AF and AE by pressing the shutter half down, that way is easy to recompose. (that is the way I did it before matrix meters)
What is your experience with center weight in bird photography
I like very much your site and find it very useful
Regards
Hi Nasim,
Is there a way to assign AE-L (Hold) to the Fn button? I want to retain the use of AE-L/AF-L for AF-On, Shutter for Shutter.
Thanks.
Hi Brent,
Depending on the dslr that you have, if your camera allows you to assign things like AE-L (Hold) to the FN button. On my Nikon d7000, I am able to set the AEL to AF-ON then set the AE-L (Hold) as my FN button. On the d7000, you go to Custom Setting Menu / f Controls / f3 Assign Fn button to assign the AE-L (Hold) function. The AE-L (Hold) can also be found unter the Controls menu. Hope that helps. :)
Mr. Mansurov,
I’m a fairly new reader of your website. I first discovered you when looking on-line for lens reviews. I then wrote to you a short time later asking your advice on a D700. You were kind enough to respond and I followed your advice. I am now in the process of reading the articles you’ve posted in your photography tips. I’ve already reprogrammed the AE/AF button on my D700 based on this article.
I must compliment you once again on the great service you have provided to amateur photographers like myself with your website. You cover all of the basics and more and do so in a straight forward and easy to understand manner. I’ve been taking snapshots my entire life but decided to make photography my primary hobby when I retired two years ago. I’ve upgraded my equipment (Nikon D700, 24-70 lens, 50mm 1.4G lens, 28-300 lens) with your help and am now reading and taking pictures every day. You have become my primary mentor so I spend some time every day reading all the existing information on your website and looking forward to the new information you send on a regular basis.
I’m sure there are days when the amount of time and effort you and Mrs. Mansurov put into this website must be exhausting and overwhelming. Please know that what you are doing is helping countless people like myself to become better photographers. Your unselfish desire to help others by sharing information and inspiration is a credit to you as a photographer and as a man. Thank you again for sharing and caring.
John Adams
Hello Nasim,
Is there any way to slightly increase the default shutter speed across the board on AF in a D7000? I just got my camera and have already come across the problem you’ve had in low light. I read your posts on a forum and many other’s posts on the problem with AF. Or is this Nikon would have to recalibrate?
& Thanks for a very informative post. Nice :)
Hi
Nice article. I allways admire people that share the knowledge on the net.
One thing I like to add: How easy it is to set the shutter and aperture to manuel. You do not have to recompose and stuff.
When you get used to that, you find out that the shutter and the aperturecontrol become the fastest way to under or overexpose. And you dont have to move a finger:)
Thank you so much for this article. My camera was stuck in one of these modes and my wife and I were going crazy trying to understand why the camera would no longer auto focus during half shutter button press. We started to think the camera was broken. You have to love the wealth of information on the internet. This info was not in the manual! Thanks again!
-Joe
Your articles are very helpful. Reading the manuals only tells you what the camera can do. Your articles help you decide what you should do. I hope you write a book. I’ll be the first in line.
Regards,
Jerry
”On higher end DSLRs with a dedicated “AF-ON” button, I always choose “AE lock (Hold)”, so that only the exposure is locked – the camera will not automatically reacquire focus when the “AF-ON” button is activated. ”
I dont get that part ( the first part is fine about AE Lock Hold)
when ”AF-On”is activated that means you are pressing the button … thats means if you move the camera it WILL reacquire focus ?
Read more: http://photographylife.com/nikon-ae-l-af-l-button#ixzz2IqlnCoBE
Nikon D5100.
How do I lock the AE-L when filming?
Do I have to press and hold it? Is it the only way?
I want to film lights blinking , but the camera are workin against me, he he
Hi Nasim,
Thanks for this article on AE-L. Just what I needed. Always puzzled why I couldn’t get the exposure to stay just where I had set it to.
Thanks for information.
It is very informative.