What is A-DEP on a Canon camera, and how do I use it? :: Digital Photo Secrets

What is A-DEP on a Canon camera, and how do I use it?

by David Peterson 11 comments

Here’s the predicament. You’re taking a picture of your family in a dimly lit room, and you want everyone in the shot to appear completely in focus. If you use the highest f-number aperture available, you know you’ll be able to get the shot just right, but there’s a problem with that. It might make your photo turn out dark. Is there a way to solve this problem? Let’s have a look at Canon’s solution.

[Family photo by: Ariane Hunter]

A-DEP Mode

It’s called A-DEP mode. The term is shorthand for Automatic Depth of Field, or just Automatic depth. With A-DEP mode, you tell the camera which parts of your photo need to be in-focus, and the camera picks a corresponding aperture guaranteed to get everything just right.

Before we get into a little more, let’s back up for a second. How does all of this work? On a very basic level, it comes down to the aperture. That’s what determines how much of your image is in focus. The aperture is the hole that light travels through to form an image on your camera’s sensor. The aperture setting is determined by the aperture value on your camera, usually denoted by an F followed by a number like F5.6 or F16.

When your aperture is fully open (a low F number), or as wide as it can get, you get the benefit of more light. This allows you to take better pictures in dimly lit spaces.

Unfortunately, this benefit comes at a cost. You get less depth of field, which is the amount of the scene that’s in-focus. More of the background and foreground get blurred, so you have be very selective about what you’re focusing on.

As you close off the aperture (higher F number), more of the scene comes into focus, but there’s a cost for that too. Less light passes through the aperture, and your images end up darker unless you also decrease the shutter speed to let in more light. And decreasing the shutter speed can lead to blurry images.

What Canon is doing with A-DEP

By now, you should start to see a pattern emerging. There’s this constant tradeoff you have to make between the depth of field and the amount of light you allow into your camera. Wouldn’t it be nice if you could only let in as much light as you need to just get the important parts of your image in focus?

With A-DEP, you can pick exactly how many of these
flowers you want to appear in focus.
Photo By: Luis Argerich.

That’s the basic premise behind Canon’s A-DEP mode. You use the system by picking a point in the foreground, then picking a point in the background, and refocusing one more time before you take the picture. A-DEP mode figures out exactly which aperture you need to use to get everything in between those two point in focus. This is the most efficient way to pick an aperture. It wastes the least amount of light.

Is it good for every photographic situation?

Arguably not. Some photographs don’t need to be taken with A-DEP mode. You can assume, for example, that you’ll want to use the smallest aperture possible for a landscape photo. In that case, you want to get everything in focus, not just whatever occurs between two points.

It’s also difficult to use A-DEP mode when you don’t have any other points of reference. A good example is a portrait of someone standing a few feet in front of a wall. Without anything behind or in front of the person (aside from the wall), you have no basis for figuring out the maximum depth-of-field necessary for the shot. You might as well just pick a wider aperture with the intent of blurring out some of the background.

Watch out - A-DEP is an automatic mode

A-DEP mode is an automatic mode, which means it doesn’t just pick the aperture for you. It also picks the shutter speed you’ll be using. A lot of photographers have expressed frustration with this because A-DEP will often pick a rather slow shutter speed when there isn’t much available light. Remember, at shutter speeds lower than 1/60s, there’s a strong risk of blur from camera shake.

A stunning high dynamic range landscape.
I would advise against using A-DEP mode
for specialist photos like this one.
Photo By: Peter Sieling.

If you’re going to use A-DEP mode in low light, be sure to bring a tripod or a flash. That’s your only guarantee of getting a shake-free image.

What results have you gotten with A-DEP mode? Was it useful, or did it just waste your time? Let me know.

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  1. Donezeco paparazzi says:

    I came up with analogy camera canon AE1, I have nikon D5000 as my first Digital (A) mode is good in production, my canon 600d also good but am have problem with my canon 6d am still waitn for EF lens to come in pls how is the production?

  2. Donezeco paparazzi says:

    Am a professional photographer from east Nigeria i was train up with M mode about two months ago i have now been using this AV mode is a good one mainly on a hot sun it don't stress me again. +23486590404

  3. WA McCormick says:

    I am not an experienced photographer, and my question about the article is how do you "pick a point"? Some of the comments leave thinking that I center on the closest point and half click to get that point referenced, then focus on the furthest point and do a second half click to reference that point and finally center the image and do a full click. Is that correct?

  4. Prabo says:

    I used A-Dep on my Canon EOS w/out knowing what it does because It got me very good pictures. Thanks for explaining what it does.
    I observe that when I use A-Dep my pictures have a blue tint compared to a fully auto picture I take on the same object or scenery. This is especially true when I take landscapes. Also the image size on the SD card is pretty large. Anyone else observe these? any reasons? Thanks. Prabo

  5. Dominick says:

    Yeah, sorta bummed that the 60D doesn't have A-DEP like the Rebel XS; I actually would use it on occasion and would get the results I desired. I was incredulous at first not seeing it on the dial, so I scoured the manual and eventually turned to forums & blogs. Guess it really wasn't used by enough folks to warrant inclusion :/

  6. Steve Williams says:

    I am fairly new to photography but I'm have had lessons. I recently shot a wedding inside a building with minimal light. I used A-dep setting and it worked well without the dreaded flash. I hate flash! Flash destroys pictures, unless you have more of a professional flash set up. Just like the articles stated its good for focal points of focus in low light. It was a learning experience but with a little lightroom my pics should be great. great post THANKS

  7. Adrian says:

    A-DEP doesn't work quite like David suggests, I wish it did I would use it a lot more. Unless I am missing something, David is describing the older DEP mode - my EOS10QD (yes a film camera from about 1990) had exactly this - you focus once on the closest item, once on the furthest and the third time to finish. It also had A-DEP where it uses all the focus points and tries to get them all in focus in one hit. Later cameras at least 20D and 40D) only have the A-DEP which I find pretty much useless. Please someone tell me I am wrong because I liked the old DEP mode using only a single focus point

  8. Jay O says:

    Canon's 60D doesn't come with A-Dep. I suppose they felt it wasn't as popular as other shooting modes and saved some space by eliminating it from their controls/features. Any other tips to accomplish the same results without a dedicated this shooting mode?

  9. Marlise says:

    I use A-Dep a lot of the time during my photography, it makes it easy to get every photo's exposure perfect without having to waste time setting it to the right exposure. Love this function, and if you just pay attention to your shutter speeds when using A-Dep you will not get blurred photo's cause you'll be prepared enough. You can also always just up the ISO if you see the exposure is a little low.

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