Using DOF for Portraits

Portraiture is perhaps one of the more obvious ways we use depth of field (DOF) as a compositional element.  By varying the amount of the scene which is in focus, we lead the viewer to see/focus on exactly what we wish them to.  We can greatly vary the ‘impact’ of a portrait through the creative use of DOF and it’s really not that difficult to do.  Lets take a look at some portraits and discuss the use of DOF in each.

Portrait with shallow DOF

This is a pretty standard portrait of a young Thai girl.  It’s a head and shoulders shot, common pose, and it includes only the parts of her necessary in such as shot so so her face is prominent in the frame without being overwhelming.  Beyond the young girl is the background and as all too common this background is not very nice (weeds mostly) and if it were in focus it would probably distract the viewer from the main subject (pretty Thai girl).  So, we plan the portrait to throw the background out of focus as much as possible.  Remember how we control DOF to get a shallow DOF?  The wider (more open) the aperture, the closer (more near your subject) the focal distance, the greater (more magnification) your focal length, the LESS your DOF.  In this portrait our aperture was F1.4, we were six feet from the subject, and the focal length was 85mm.  We couldn’t have moved closer with a 85mm lens because her head/shoulders took up the entire frame at this distance.  We could have increased the focal length to 135mm or 300mm, which would have required increasing the focal distance for proper framing, so in this case increasing focal length would have been a wash.  I wanted the background as out of focus as possible for this pose.

The only other thing I could have done was open the lens one stop wider to it’s maximum of F1.2.  Why didn’t I do that?  Take a look at her eyes.  In this view you can see that at first glance both appear in focus.  Look closer.

Focus on the closest eye

Notice that her CLOSEST eye is in very sharp focus, but her other eye is slightly blurred?  At these settings our DOF is only 3 inches, less distance than from eye to eye.  The focus point is her closest eye, and from there we lose focus outwards.  The portrait works, but I caution you.  Shooting at F1.2-F2 requires special techniques and a lot of experience and patience.  Many people buy the lens, try this, and end up thinking the lens is defective.  It’s not, it just takes knowledge, experience, skill, and patience.

Deeper DOF

Look at this next portrait.  Pretty much the same, but with two major differences.  The pose allows more of the subjects body in the frame which means a longer focal distance, and the background being grass and flowers is far more attractive so we don’t need it to be as out of focus as the last one.  Remember how we control DOF?  The wider (more open) the aperture, the closer (more near your subject) the focal distance, the greater (more magnification) your focal length, the LESS your DOF.  Sorry, I can’t repeat this line enough.  We need to memorize it and be able to quickly process the variables as we shoot portrait..  Same camera settings, 85mm focal length, aperture F1.4, but the focal distance has increased to roughly 12 feet.  This gives us a DOF of six inches, plenty to keep both eyes in focus, and hair on both sides of the face.

Both eyes in focus

Can you see how both eyes are sharp and in focus?  The eyebrows are well defines, skin pores evident, wisps of hair sharp?  As an added note, notice that she isn’t looking at the camera?  A subject doesn’t always need to engage the camera, often the portrait will be enhanced if they don’t.

Extended DOF

This portrait extends the DOF even further out, but this one gets a bit tricky.  She wanted to clearly show she was in her Jeep, but the background was less than attractive and definitely a distracter.  I was able to compute DOF in my head as I was composing the shot and roughly determine the settings necessary to keep the subject and the Jeep in focus, and the background out of focus.  The settings were 85mm, F4, and a focal distance of roughly ten feet.

Portrait with props included

This next portrait needed to say and show more than a face.  This lady worked making brooms and brushes and I wanted the portrait to be more environmental, to show her workspace, materials, and tools of her trade.  Everything needed to be in focus in the entire frame.  The settings were 73mm, F8, and a focal distance of roughly 15 feet.

Definition:  I’m sure you’re wondering what that out of focus area is called?  The out of focus portion of the image is called BOKEH.  This is a Japanese word and originally meant beautiful, smooth, and out of focus, the components of “desirable” bokeh.  Notice how smooth and creamy the bokeh is in the first two portraits?   Bokeh is created/effected by the aperture, lens, number of aperture blades, and settings.  The best lenses will normally have the best bokeh and nine aperture diaphragm blades.  In this case I was using Canon’s excellent 85mm F1.2 USM L lens, roughly a $1500 lens.  In the last environmental portrait, as in most studio portraits, bokeh wasn’t desired so I choose a quality zoom lens for it’s sharpness, color and contrast, and the zoom which makes my job as the photographer much easier.  This was a Canon 24-70mm F2.8 USM L lens, roughly $1200.  It has seven diaphragm blades.  It’s bokeh is “ok”, but noticeably more rough and not nearly as creamy and soft.  There are many $200-$300 zooms capable of creating bokeh, but the bokeh becomes so rough and unattractive that you hate to use the camera that way.  Bokeh is a major consideration of a professional photographer specializing in portraiture and weddings.  We’ll often change the lens out with one of the same focal length, just because we’ll get better bokeh with the other.