What is Depth of Field?

DOF Explained


Depth of Field is the range of distance that appears to be acceptably sharp in your photograph. What does that mean? Well, when the background of your image is blurry you have a shallow depth of field. This is because the point you are focusing on that is in focus is quite small. On the other hand, if you take a picture of a landscape and the whole thing is in focus from front to back, that is what we would call deep depth of field. That's when most or a large area of the image is sharp and in focus.


When you focus on something, the area in front of the subject is out of focus, and the area behind the subject is out of focus. The aperture controls how deep or shallow the area of IN focus is. This is where we get to that professional photographer signature look of the out-of-focus background. Remember, the size of the aperture is measured by what is called the F-stop. The larger the aperture, the smaller the F-number, the shallower the depth of field is. This means that f/1.4 is going to give us a much blurrier background than f/8.  Using the aperture (f-stop) of your lens is the simplest way to control your depth of field as you set up your shot. 

But there are other things that will factor into depth of field.  For instance, the closer your subject is to the camera, the shallower your depth of  field becomes. So then, moving further away from your subject will  make your depth of field deeper.  Then there is focal length. Simply put it is the capability of any particular lens to magnify the image of a  distant subject. This can seem a bit complicated, but here is  the basic rundown -  the longer you set your focal length the shallower the depth of  field. Let's say that your subject is about 30 feet away. and you are using a focal  length of 50mm at f/4 you will have a certain depth of field and  If you  zoom into 100mm from exactly the same spot, the depth of field changes will now be shallower (more background blur). 

So in summary, depth of field can be determined by your aperture, your distance from the subject you are photographing, and the focal length of your camera lens.