Getting out of Auto – Understanding Aperture Priority.

I talk to a lot of people who want to get out of shooting in Auto mode to gain more control over their settings, but don’t know how to do so. The main obstacle preventing them from doing so is confusion surrounding the function of each camera mode and also a fear of permanently stuffing up the camera settings.

In the next few posts, I’ll do my best to explain the various shooting modes that exist on most cameras. These are: aperture priority, shutter priority and manual.  These may be labeled differently depending on the camera manufacturer, but essentially, they all perform same the function.

It’s shouldn’t be intimidating and by the end of the series, you should develop a sound understanding of each of the camera modes, when to use them and how to set it up for the particular type of shot you are trying to achieve.

What is aperture?

In a nut shell, aperture is the opening and closing of the blades in the lens to control the amount of light that enters. Having the camera set at aperture priority allows you full control of how much light is allowed let in.

In camera speak, having the aperture “wide open” is when you have the most amount of light being let in. Conversely, when you have the least amount of light coming through the lens, it means that you have a narrow aperture.

You’ll read in literature or on videos, the aperture settings as being referred to F-stops. i.e f2.8, f8, f14 etc. Where the greatest confusion surrounding aperture settings is that the wider the aperture, meaning the more light that the lens lets in, the smaller the F-stop number becomes. It is confusing at first, but after a few tries, you do become used to it.

aperture settings

The circles represent the size size of the aperture.

Aperture and depth of field.

The aperture also allows the ability to control the depth of field on your camera lens. Depth of field is the the distance between the closest and farthest areas in the image that remains in focus. A shallow depth of field is when a limited distance remains sharp, whereas a wide depth of field is when most of the image from front to back remains sharp.


An example of a shallow depth of field where a small area of the image is in focus to remove the distracting background. Aperture setting is set at f2.8.

The camera lens cannot see everything in focus like the human eye can, so we must tell it at how much of the image should be in focus. This allows for greater creativity and also separation of the subject from the background, which makes gives more of a three dimensional look to a two dimensional image and also adds a creative flair to it.

When should I use it?

You should be thinking about depth of field all of the time. Personally, I have it on aperture setting 99% of the time that I shoot. The easiest question to ask yourself is, “How much of the subject relative to the entire scene or image do I want to be in focus?”, and then experiment with your settings from there.

How should I use it and what is a good aperture setting?

There’s no right or wrong answer to this, but it will come to the single most important question that you should ask yourself every time before you press the shutter button: What is my main subject, and how much of that main subject do I want to showcase in relation to the overall scene? This would apply all of the time whether you’re in aperture priority mode, program mode, auto or shutter priority mode.

The simplest rule of thumb that I tell most people are as follows:

f2.8 for a shallow depth of field for maximum separation between subject and the background.

If you’re shooting an object or a person, and you want a clear separation of the subject from a distracting background, then you will want a shallow depth of field. This will require an f-stop value as low as your lens will allow you to go. Most mid to high range lenses will go down f2.8 and kit lenses will go down to f3.5.  I’ve seen photographers use this method when it just possible not to have control over the location of the shoot, so they use it to blur the background out.

aperture priority

If you have distracting elements in the background, set your f-stop value as low as it goes. In this case, f1.8. For a scenario such as above, make sure that both people are standing as square to the camera as possible, otherwise one person will be out of focus.

f5.6 for more context.

If you want the background to show context still, such as a well known entrance to a building, then set it at around f5.6. The amount of blur will require some experimenting but also the distance between the subject and the background will have an effect on it. The closer the subject is to the camera and further away they are from the background, the more blur there will be. Make sure to have your lens zoomed in and the focusing points right on your subject so it can determine what needs to be in focus.


Here, I wanted the statue to be sharp and in focus and the church spires to retain some detail by using f5.6 aperture setting.

f8 to keep everything in focus.

For buildings and landscape photos, you want as much detail as possible from the front to the end of the image. Most lenses have a “sweet spot” between f8-f11 where everything will have its maximum sharpness from the centre to the edge of the image. You can check by taking a series of tripod mounted shots from f8-f11 and examine the pixel quality. If you’re lazy like I am, set it at f8 and you should be  fine.

camera aperture settings

f8 will ensure that the entire image is sharp from centre to the edge of frame. Image of Lotfollah Mosque in Isfahan, Iran.


One Response to Getting out of Auto – Understanding Aperture Priority.

  1. Mick January 24, 2015 at 12:32 am #

    AP is my jam!

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