This post is about "Depth of Field", which made me think of the song "How Deep is Your Love?" because when I decide on what depth of field to use in making my images, I actually do think about my subject and how much I want to focus on them either to the inclusion (for context), or the exclusion (for highlighting) of everything around them.  The website Digital Photography School tells us that Depth of Field is "the zone of acceptable sharpness within a photo that will appear in focus. In every picture there is a certain area of your image in front of, and behind the subject that will appear in focus." The article goes on to say "Three main factors that will affect how you control the depth of field of your images are: aperture (f-stop), distance from the subject to the camera, and focal length of the lens on your camera."

Remember when the Apple iPhone 7 came out with all those commercials touting "portrait mode" for the camera? It was mimicking DSLR depth of field controls to isolate the subject from the background.

So while taking "for sale" pictures of my husband's 1964 Chevelle this morning  (anyone want to buy a car?), I decided to pose my own dog Ginger in the front seat and play around with depth of field.  I kept two of the three variables the same; I used the same lens for all four images and shot at the focal length of 44mm for each image and I maintained the same distance from my subject - only the aperture, or f/stop (the opening of the diaphragm inside the lens) changed.  

The image below was photographed at f/9, and while I focused on Ginger's eye, you can see that the passenger door behind her is in pretty good focus.  I do want my viewer to know that she's posed in a car, but do I need the door in focus? No. There are plenty of other elements in the frame that put her in the context of a car, and I think it's distracting me away from her face.