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.
In the image below, I opened my aperture a bit bigger to f/6.3, one full stop larger and made the necessary adjustments to my shutter speed and ISO to maintain the same exposure. Better, but I still think the passenger door is too much in focus and detracts from what I want to solely hold the viewer's eye, and that's my subject Ginger.
So let's go down one more stop to f/4.5 and take a look; even though the numbers are getting smaller, the opening of the diaphragm is getting bigger which narrows the depth of field giving us a "smaller slice" of what's in focus (see graphic below).
I like the image at f/4.5, but lets open up one more stop to f/3.2 just to see if like that one better.
For my personal tastes, I like the f/4.5 image (below); I do want the background out of focus but not so much that the viewer has to work hard to figure out the setting and context of where my subject is posed (I also like her pose better in this image).
Tracy Allard of Penny Whistle Photography is a Certified Professional Photographer with the organization Professional Photographers of America; a designation held by fewer than 2,500 photographers nationwide and a hallmark of consistency, technical skill, artistry and professionalism. Penny Whistle specializes in both natural light and studio photography providing family and pet portraits as well as corporate headshots and commercial photography in her studio located in old town Carrollton as well as out on location in Coppell and surrounding communities in Dallas – Fort Worth, Texas.