Camera lens Aperture Complete Guide


Aperture is one of the three most important aspects of photography. The other two aspects are ISO and shutter speed. These three elements will determine the quality of the image you get when shooting in different environments. Understanding Aperture is a necessity if you are going to be using your DSLR camera.

What is the Aperture on a Camera?

Aperture is one of the most important aspects to master when taking photographs with your DSLR camera. The reason for this is because it has a direct effect on your image, it can either blur the background bringing your subject into focus or it can bring everything into focus on your photograph, this all depends on what aperture you are using. As you can see, getting the perfect shot depends a lot on your aperture.

The aperture of your camera is quite simply a hole in the lens which allows light to travel into the camera body. The larger the aperture, the more light is allowed to pass through and conversely the smaller the aperture the less light will pass through, and this will affect your image quality. Apertures are measured in f numbers, the larger the f-number, the smaller the aperture and vice versa.

Another important aspect that your aperture will affect is your depth of field. The depth of field is how your camera will focus on the subject you are photographing. The aperture will affect your depth of focus which in turn will determine how fuzzy or in focus your background picture is, and how sharp your subject will appear in your image.

An example of this is if you set your aperture at let’s say f/32 then you will get a great picture with both foreground and background in complete focus as your aperture is set at a small setting. And if you set it at let’s say f1.4 then you will focus on the subject such as a person or object and the background would be blurred out.

All lenses have a limit as to the size of the aperture available, a minimum and maximum aperture and you will have to read your lens manual to determine this. Remember the higher the f-number the lower the aperture and vice versa. Typically it is the maximum that is important as most modern digital cameras have enough aperture to allow for normal, everyday photography, such as your point and shoot versions.

The size of the circle will represent the size of the lens aperture. The large the f-number determines the size of the aperture. A larger f-number equals a smaller aperture. The iris of the lens which controls the size of the aperture is known as the diaphragm.  The sole purpose of the diaphragm is to limit the amount of light that is let into the lens through the aperture.

Therefore the smaller the aperture the less light the diaphragm will allow through. There is two type so lenses, namely fixed and zoom. Zoom will allow you to zoom in and focus on a subject you have selected. Most of the lenses have variable apertures, depending on how you are zooming. So if you are fully zoomed out the aperture will be the lowest number and if you are zooming in the number will increase.

Aperture Settings

Aperture settings will depend entirely on you and what kind of image you are looking for. For portraits, you would use a very low f-number which equates to a wide aperture, this will ensure that your backgrounds are slightly blurred and your subject is the focus of the shot. If you chose a middle of the road aperture such as a f/8 you will get an overall shot with nothing as too sharp and nothing to blurred.

Finally choosing a higher number, which equates to a lower aperture, you will get everything in sharp focus, this is the kind of aperture you can expect from your point and shoot a variety of cameras.
For landscape shots or nature photography, you will need to assess the lighting and more before selecting your aperture. Changing the size of your aperture will also affect the depth of your image.

How do F stops work on a camera?

Your f-stop number is the number that determines what your aperture is set at. A low f-stop number will open the aperture to its widest size. When taking close-ups and you want a picture that has very sharp focus you will want to use a low f-stop to open the aperture to its widest. An easy example to give you an indication of how the f-stop works on your camera is as follows:

You have a camera with a 100mm focal length. Your aperture would be set at 10mm which is a f/10 f-stop number. Remember that the higher the f-number the smaller the aperture. In point and shoot cameras your aperture is automatically controlled for you. Or you can set your DSLR to aperture priority or Av and let the camera control your aperture for you.

Which Aperture is Better for a Mobile Camera?

Here it is difficult to determine what the best is for your mobile’s camera. Some of your mobiles such as the iPhone, come with dual apertures so you can choose depending on what kind of depth of field you want. Mostly though your mobile phones do not have great aperture settings which means taking both distances and close up shots do not come out clearly, they have an average aperture and this is perfect for your arm’s length shot.

However, phones such as your iPhone 7 have two settings an f/1.8 which is for your zoom or telephoto lens on your camera and then the f/2.8 which give you a smaller aperture for close up shots. Combining these two will offer you a reasonably shallow depth of field effect and the best image you can expect from your mobile.


When choosing the right aperture is vital not only for your image quality but your depth of field. Getting that perfect sharp portrait image you will need a lower aperture that will fade the background and sharpen your subject. For landscapes it is not as easy, it depends on light and environmental conditions to get the right settings.