Conventional “wisdom” on the forums is that the ONLY way you can create good Bokeh is with apertures of f1.2, f1.4 or at lest f2.8 and that you MUST use the 85mm or a 50mm to achieve the best results.
As a professional photographer, with over 40 years experience, I’m here to tell you they are wrong on ALL counts! Because I really like bokeh, being a portrait photographer, I must control my depth of field to the benefit of my subject. The Bokeh is not my subject—it is the background behind my subject. Therefore, I can’t risk using the razor thin depth-of-field I would get using f1.2, f1.4 or f2.8 for portraits.
So, to create really nice bokeh I use my telephoto lens, usually 200-300mm, and proper placement of my subject; keeping my subject far from the specular highlights in the background for the look I want.
f2.8 @ 1/15 sec., ISO 400 Lens @ 200mm
n the example above I used f2.8 because the small subject requires little depth-of-field. But, what makes the big bokeh here is my lens being at 200mm. In addition that long focal length knocks the background so out of focus the you can’t see the source of the bokeh.
The following images dramatically show how the focal length affects Bokeh at the same f-stop.
As you can see not only is the bokeh smaller in the left image, but you can clearly see the source of the lights; the Christmas tree.
To further prove the power of focal length over f-stop for good bokeh…
f8.0 @ 1/1000 sec., ISO 400; Lens @ 200
That’s some pretty nice bokeh for an aperture of f8.0! It’s all about focal length and distance of those specular highlights from the subject.
NOTE: When outdoors your specular highlights are usually created by backlight. If there’s no backlight (best towards sunset) you’re not going to get bokeh that is alive with light; if there’s no light in the background it’s a dead background, which is useless to me.
So, this is what I make a living doing—Portraits of People (mostly outdoors) by natural light one or two hours before sunset.
f4.5 @ 1/250 sec., ISO 400; Lens @ 160mm
The most useful aperture for individual portraits that will also give me nice backgrounds is f4.5 . At that aperture I always get both eyes in focus even if I have my subject turn to a 2/3rds view of their face. In the above image my focal length was only at 160mm, so the background is nice, but not as soft as I usually prefer.
f4.5 @ 1/320 sec., ISO 400; Lens @ 280mm
Now this is what I’m talking about! So, I could really compress the scene—bringing the background and the little girl together—I mounted the Canon 1.4x extender on my Canon 70-200mm f2.8 lens giving me a maximum of 280mm to work with on this session.
My basic rule in portrait photography is to use the MOST telephoto lens I can when photographing people because compression distortion ALWAYS makes people look better than the extension distortion created by any short 50mm or less lens. And, my backgrounds look way better at 200-280mm than those popular lenses in the 85mm range can create.
As usual, have a question don’t hesitate to ask….
Author: Jerry W. Venz, PPA Master Photographer, Craftsman, Certified
Training site: http://www.LightAtTheEdge.com