Using Shallow Depth of Field

A wide, f/2.8 aperture and a long focal length produce a narrow depth of field that makes this seagull pop out from the background

Yes, it was only a few weeks ago that I presented another seagull photo. Please excuse the redundancy as it enables comparisons in photographic approaches. (You can also see the differences and similarities of southern California seagulls and the Lake Erie seagull, above - to my eye, it is mainly the beak).

In the previous photo, the seagull was presented against a field of blue sky and the white bird popped out against that background. In this case, nearby pilings and a busy distant shore threatened to compete with the bird. A shallow depth of field was needed to isolate the seagull from that busy-ness.

Fortunately, I had the right camera and lens with me to make the shot - the critical piece being the 70 - 200 mm lens with a maximum f/2.8 aperture. The depth of field was so narrow that the bird's eye and beak, and the face of the piling (which is in nearly the same plane), are all in focus, while the bird's feet and legs are not.

In the previous seagull photo, since the background was clean and provided good contrast, I could use the minimum aperture of the lens for deep depth of field. This made for crisp photo sharpness of the entire seagull and it's perch.

Photo Critique

Shallow depth of field is key to the success of this seagull photo because it: takes the viewer's eye right to the seagull's eye adds complementary visual interest with the pattern of the pilings and provides a smooth background behind the seagull's head As compared to the previous seagull photo, this one does a better job of preserving highlights - there is more detail in the whites of this bird than in the other, although that might be hard to see in the reduced photo size. I used a slight negative exposure compensation of 1/3 stop to help avoid blowing the highlights.

This was a sunny, clear day, but the photo background is a bit too muted to convey that. The next step with this image would be to lighten the river and shore without impacting the highlights on the bird. Also, my ISO was set at 400 because I had been shooting in the shade before walking out to the dock. The Nikon D300 shoots very well at ISO 400, but I still believe in shooting at the lowest possible ISO to gain every bit of photo sharpness advantage available, and that would have still left me with a 1/4000 second exposure.

If you'd like to learn more about depth of focus and field, go to this photo sharpness page.