One of my guiding principles in portrait photography is to create the least depth-of-field I can while still keeping my subject(s) sharp. So, the f-stop is my most important variable. All the other variables, shutter speed and especially ISO, are used to get me to my preferred lens aperture to give me the depth-of-field I want.
Most professional photographers have preferred working lens apertures for each type of photography we do. Why? We must deliver the goods on EVERY session we do so we must know what f-stop, lens focal length, distance from your subject, sensor size, combination that will create the depth-of-field required for any type of subject(s) set-up.
In portrait photography my subject depth-of-field (DOF for ease of reference) is mostly determined by how many people and the pose we place them in. The following image shows a family we posed in a single row group (our “walking pose”) that does not require much DOF—Super Simple!
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f5.0 @ 1/125 sec., ISO 400
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The DOF data for this image is: Camera - Canon 5D MKII with 70-200mm f2.8 lens:
- Focal length: 200 mm
- Distance from subject: 40 feet
- Aperture: f5.0
- DOF = 3.63 feet
This next image with a larger family group that needed to be compressed into THREE Layers, so the group didn’t get too wide, needed much more DOF.
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f7.1 @ 1/125 sec., ISO 400
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The DOF data for this image is: Camera - Fuji S-5 Pro with 80-200 mm f2.8 lens:
- Focal length: 112 mm
- Distance from subject: 30 feet
- Aperture: f7.1
- DOF = 6.34 feet
When doing individual portraits the pose (the angle of view of the face) determines my aperture. In the portrait of the boy below I didn’t need much DOF because he was in Profile.
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f2.8 @ 1.250 sec., ISO 800
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The DOF data for this image is: Camera - Fuji S-5 Pro with 80-200mm f2.8 lens:
- Focal length: 200 mm
- Distance from subject: 15 feet
- Aperture: f2.8
- DOF = 0.19 feet (2.4 inches)
Since we only see one eye you can get away with very little DOF and being at 200mm gives you great bokeh as well!
This next image of the young lady is typical of a pose when you see Both Eyes. We have her body turned away from the camera and her nose is not pointed directly at the camera. In this pose I can’t take any chances with DOF being so shallow that I lose focus on the far eye so, f4.5 is generally where I am for this pose.
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f4.5 @ 1/250 sec., ISO 400
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The DOF data for this image is: Camera - Canon 5D MKII with 70-200mm f2.8 lens:
- Focal length: 160 mm
- Distance from subject: 10 feet
- Aperture: f4.5
- DOF = 0.3 feet (3.6 inches)
In summary these are MY favorite working apertures:
- f7.1 …. for groups 3 or 4 deep
- f6.3 …. for single families up to 3 deep
- f5.0 to 5.6 …. for a single row group
- f4.5 …. for a individual in most poses
- f2.8 …. for an individual in profile
All of the DOF data was gleaned from fttp://www.DOFMaster.com . It’s a great website where you can quickly get your camera specific depth-of-field information for most camera-lens combinations. All you need to do is plug in your typical “shooting” distance and favorite f-stop to instantly get your depth-of-field. When you go on the site simply scroll down to their “On-Line Depth of Field Calculator” to get more than you thought you never needed to know about Depth-of-Field!
If you are having trouble with sharpness in your portraits I hope this information will give you an insight on how to make corrections and greatly improve your photography. Let me know if you have any questions or comments….”Till next week…
Author: Jerry W. Venz, PPA Master Photographer, Craftsman, Certified
Training site: http://www.LightAtTheEdge.com
