When you start taking pictures, any type of pictures the first thing that you get to understand is how the depth in a photo works but contrary to popular belief depth of field is actually the area in focus. The subject no matter where they are in a picture or if a landscape is the subject any part that is in focus, while the other parts are not, is the depth of field.
Coming to understand the shallowness and the deepness of it the tricky part; when the subject in the photos is focus and the areas behind and forward are not it makes for a shallow depth while the greater the area in focus the deep the depth will be.
The depth is the always there, even when everything is in focus (f.22) there is still depth in the picture, it’s just very deep. There are several things that effect and influence the DOF however and these things manly include
- Focal length
When the distance from the subject is greater the depth will be different as compared to a closer distance, perspective along with the depth are effected when a person moves closer to the subject. Let’s say that the aperture is wider and the lens is 50mm, when the distance is further the same depth of field will become even deeper when you start to move closer to the subject.
Aperture is what mostly controls the deepness and shallowness when taking a picture, after the lens is fixed and the subject is places; aperture is used mostly to control the area which will be in the focus and which parts won’t be. The focal line starts to widen and get deeper when the aperture is lesser (e.g f.2.5) and the depth starts to become deep and wider when the aperture is increased and focus is on more wider and sharper (eg f.22) .
The next thing that effects the depth of field is the focal length, the lens that is used in a shot will distinguish what type of photo will come out, if the greater the focal length of a lens the wider the depth will start to get, you can take more shallow depth pictures with a 85mm than you can take with a 300mm. portraits usually need more shallowness to create that blurry effect behind the person called bukeh so for portraits the lens that allow more shallowness will be used like 50mm or a 85mm.
The topic of lens usage is itself so complex and deep that it will be covered in another post but for now, the larger the focal length the deeper the depth will be.
These three things combine and effect the Dof in a picture, the main thing is to experiment with different lens, distance and apertures to understand how each effects the depth.
Practice makes perfect, that’s what we say.