Project 52- Depth of Field

Our blog topic for this week is DEPTH OF FIELD!  If you're not a photographer, you may not have any idea what this means and that's okay!  My goal with writing these blogs is always to try and impart a little bit of knowledge for those looking to learn more about photography.  

Depth of Field is basically the portion of the image that is in "acceptable focus".  Acceptable focus does not mean perfectly sharp, but sharp enough to still appear to be in focus.  This range can vary widely from image to image.  In landscape photography, the goal is often for the entire image to be in focus.  When taking portraits, we often try to have some separation between our subject and the background so that the focus (no pun intended) is on our subject.  In other words, depth of field varies depending upon the goal of the image and thankfully we can control that!

So, how do we control depth of field?  One way is by changing the aperture.  The aperture is the variable opening through which light enters the camera.  We measure this opening in f-stops.  The smaller the f-stop number (like f2.8) means the larger the opening. This lets more light into the camera and gives you a SMALLER depth of field.  The larger the f-stop number (like f22) means the smaller the opening.  This lets less light into the camera and gives you a LARGER depth of field.  Clear as mud, right?  Let's look at an example...

In this first image, I set my aperture to f/9.  My subject is sharp and you can still see a good amount of detail in the grass and trees behind her.

This image is taken at f/2.8.  Same focal length and same distance from my subject, Zoey.  Zoey's face is sharp, but the focus starts to drop off dramatically.  You very little detail in the grass and trees behind her, but you can still tell that they are trees.

Another way to control depth of field is by changing the distance between you and your subject.  The closer you are to your subject, the smaller your depth of field.  The further you are from your subject, the larger your depth of field.  When photographing a subject in a "less than desirable" location (like my backyard), I prefer to get closer to and fill the frame with my subject.  I use a wide aperture and a longer focal length to get the greatest amount of separation between my subject and the background (which also produces beautiful "bokeh" or blurry background).

This image was shot in the exact same location also at f/2.8, but I moved back further and zoomed into 75mm.  You know that there are trees and dead grass behind her because of the previous images, but they are virtually unrecognizable here.

There are actually depth of field calculators out there where you plug in your camera model , focal length of your lens, aperture, and distance to your subject.  It will then tell you how deep your focal plane will be or, in other words, how much of your image will be in acceptable focus.  If you find this calculator helpful, you can also download apps on your phone that will do the exact same thing!

I hope this was helpful for you!  I highly encourage you to check out Wag to my Heart Photographer, Danyel Rogers, providing photography needs for the Portland Metro area.  Understanding depth of field can be a bit overwhelming, so reading through the blogs this week will be a great way to start to wrap your head around it.  Please let me know if you have any questions and THANK YOU for stopping by!

~Kelly

 

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