Like a Good Wine, Photos Can Have a Great Bokeh
What in the world is bokeh, you ask? Bokeh [pronounced bo-kay]comes from a Japanese word, boke-aji, roughly translated as "blur quality". The term refers to the aesthetic qualities of a blur produced in out of focus parts of an image. Another description might be that under the right circumstances, a shallow focus provides a more pleasing image than an image where everything is in sharp focus.
I've become more aware of this quality and how to take advantage of the effect over the years. Most photographers are aware that the aperture setting can influence the depth of field of an image. Larger apertures let in more light to the either the piece of film or sensor array. Without going into the physics, a smaller aperture (higher f-stop), gives greater depth of field. So generally, with a higher f-stop, both the major object will be in focus, as well as the background, while with a smaller f-stop (larger aperture), the main object will be in focus, but objects in the foreground or background may not be.
Steller's Jay with Acorn
Coyote Creek Nature Trail
San Jose, CA
f/5.6 1/800sec
This photo of a Steller's Jay with an acorn in its mouth was taken with a fairly large aperture. The foreground image of the bird is in focus, while the background trees are out of focus. This image was taken in late fall in California, so some of the leaves had started turning brown. The blurry image in the background allows the eye to concentrate on the bird and not be distracted by the jumble of tree limbs and leaves in the background. The background also provides a complementary abstract palette for the bright blue and black feathers of the jay.
Squirrel with Walnut
Coyote Creek Nature Trail
San Jose CA
f/5.6 1/1250 sec
This cheeky devil was also photographed using a large aperture. The squirrel and branch are in sharp focus, but the background is blurred, which eliminates any distractions from the central image.
Bee on Rosemary Flowers
San Jose, CA
f/7.1 1/800sec
In this photo, the aperture is higher than the two previous examples, but we still have a sharp foreground image, with the background blurred to the point that it is a series of colorful dots. This image was taken using a 500 mm telephoto lens and the object was between 1.5 - 2 meters away (5 - 7 feet). Under these conditions, a telephoto lens will have a very shallow depth of field, regardless of the aperture. [A macro lens will also have a very shallow depth of field.] Let's see how we can take advantage of this, using the next few images:
Anna's Hummingbird with Mexican Sage
San Jose, CA
f/14 1/800sec
The soft, almost impressionistic background in this image is the result of the tight field of focus of the telephoto lens. I was about 5 meters (15-16 feet) away from the hummingbird. You can see that one of the Mexican sage flower stalks is in the foreground, but blurred. This helps give a three dimensional quality to the photo that might be lost if everything was in sharp focus.
Ithuriel's Spear
(aka Wally Basket or Grass Nut)
San Jose, CA
f/18 1/1250 sec
Ithuriel's Spear is a native California wildflower that blooms from April - May. This image was taken with my telephoto lens at ~ 200 mm from about 3 m (10 ft) away. The field of focus is deep enough to get all the flower buds in focus, but the background grass is blurred enough to not detract from this spectacular display.
Cherry Blossoms
San Jose, Ca
f/22 1/400 sec
Before it became Silicon Valley, the San Jose area was known primarily for its fruit and nut orchards. Some fruit and nut trees remain, either isolated holdouts, or as ornamental trees planted in industrial parks. This image was taken with my telephoto lens at 500mm from about 2 meters (6 -7 feet) away. The narrow depth of field provides a narrow field of focus, and with the high aperture, gives a nice interplay between the bright flower petals and the darker branches and the side of a building behind, which has been de-focused to random light and shadow.
There are times when the narrow field of focus of a telephoto lens isn't as noticeable or even desired. The next example shows one case:
Squirrel with Acorn
Alameda Creek Trail
Fremont, CA
f/11 1/800 sec
First of all, what it is with squirrels and walnuts? I wonder how they manage to ever open them up. [Back to the primary topic... ]This photo was taken using the telephoto lens at 500 mm from a distance of about 10 m (~ 40 ft), and so the field of focus has broadened considerably. The grass and rocks in the background are slightly blurry, but just barely, which does give some three dimensionality to the photo.
Adolescent Gulls Taking Off
Alameda Creek
Fremont, CA
f/11 1/800 sec
This photo captures the moment when two young gulls take off from a shallow creek. Once again, the telephoto lens is at 500 mm, but it was important that the entire image be in focus. Fortunately, I was taking this picture from a bridge and was about 15 m (50 feet) away., so the depth of field was wide enough so that the flight feathers of both birds are in focus.
There's another technique that can give a blurred background: panning. This is where you track (or attempt to track) the movement of a moving object with the camera and use a fast shutter speed (and hope your object of interest is still in focus when you snap the shutter).
Red-Tailed Hawk with Gopher
Oakhurst, CA
f/8 1/250 sec
This photo was taken at my sister and brother-in-law's home outside of Oakhurst, CA, in the Sierra foothills. The gopher had been killed in a trap earlier that day and my brother-in-law had put the "prey" on a rock in their back yard. We waited for a hawk or vulture to notice it and I was able to get get this shot and a couple of other shots by panning the camera with the hawk's movement. At the time, I didn't yet have my 500mm zoom lens and only had the 70-300mm zoom; this shot was taken with the zoom at 300mm. I was still getting to know the D500 body and for some reason, instead of shutter priority, I was in full automatic mode, which explains the relatively slow shutter speed. Today, I'd be sure to be in shutter priority with a shutter speed of at least 1/1000 sec or less. Still, I managed to get a decent shot and the pan produces a blurry background that conveys speed and motion.
Female Mallard, in Flight
Alameda Creek
Fremont, CA
f/16 1/1000 sec
Here's another case where I panned the camera with the bird and took a succession of shots, of which, this was my favorite. One of the toughest things when shooting birds in flight is to get a neutral background that doesn't distract from the bird. Here, the combination of the sand and rocks is sufficiently blurred that it doesn't interfere with the bright patterns of the mallard's wing feathers.
Gadwall, in Flight
Alameda Creek
Fremont, CA
f/11 1/800 sec
This was another photo taken using the panning technique with the 500mm telephoto lens. I happened to catch the bird's flight out of the corner of my eye and turned and managed to track it as it gracefully started a bank and then landed (Unfortunately for me, there was a bridge support between me and the actual landing spot.), By panning, I was able to blur the other side of the creek enough so that it doesn't distract from the bird's plumage. It also gives a nice three dimensional feel to the image, as the gadwall seems suspended in the foreground.
