Monday, May 18, 2009

Focus, overcoming the "fuzzies" Part 2

Filbert Street stairs, San FranciscoIn Part 1, I discussed how auto-focus works, and many of the modes of auto-focus found in today’s camera’s. In Part 2, I’ll discuss how to use auto-focus, difficult auto-focus situations, and when to manually focus your camera if it has that capability.

A not so famous photographer said in 2007, “Out of focus photographs give me a headache.”¹

Visiting the National Zoo’s panda exhibit where the glass wall separating visitors from the bears has a zillion finger prints and other dirt, travelers notice their photographs of the Pandas are out of focus, but the fingerprints on the glass are “sharp as a tack.” Seriously, wouldn’t that give you a headache?

When I first started pursuing photography seriously, auto-focus wasn’t even a dream, but today, auto-focus is the standard, and on most cameras, in most situations it does an outstanding job, more quickly, and sometimes better than photographers can do for themselves. Please note the use of the phrase, “in most situations,” and the word “sometimes” in the previous sentence.

If you want your photographs consistently to be in focus, care and thought must be given to the process.

For good auto-focus the photographer must be cognizant of how auto-focus works. For stationary subjects, the general technique used when auto-focus is difficult is called, “focus and recompose.”

LACMAUtilizing your knowledge of how auto-focus works, you allow the camera to find the ideal “focus” for your photograph, then, after locking-in the focus, compose, or rather “recompose” the image to that desired. This is only possible if your camera permits manual focus lock. Most auto-focus cameras utilize the shutter release button to lock the camera’s auto-focus when the button is pressed halfway down. As long as the button is not released, the focus will be locked, and remain locked until the photograph is taken by pressing the shutter release all the way.

We already know, to auto-focus, the camera must find the edges of your subject on which to focus by sensing the differences in the scene’s contrast. For difficult to focus stationary subjects I use single area focus and directly point to an edge or line on the subject. If that won’t work, I’ll focus on another object, equidistant to the subject of the photo. I lock the focus and compose my image, all the while holding the shutter release halfway down, then when ready, take the photo.

Sometimes, if conditions permit, I close the aperture of the lens to the extent possible to lengthen the depth of field, to better ensure good subject focus. That can have negative results, however, if it brings into focus, objects you would rather have out of focus to make your main subject stand out.

Pelican flying in the GalapagosFor subjects in motion, such as birds, I suggest using continuous group dynamic focusing. This allows the camera to use multiple focus points to auto-focus, so if the subject moves for a moment, away from the photographer’s primary focus point, it will remain in focus while the photographer pans the camera to keep composing the image as photographs are taken. This mode, allows the camera to more easily find those elusive edges for focusing on moving objects. A method to assist you focus on a moving subject, such as a bicycle rider, is to prefocus on something which is stationary and equidistant from where the rider will be going across your field of vision.

Lion at the San Diego Wild Animal ParkSometimes, the camera’s auto-focus can be fooled into focusing on the wrong subject. The National Zoo’s Panda exhibit mentioned above is a perfect example. At zoos, we want to take photos of animals behind glass or chain link fences, but our cameras often auto-focus on the glass or fence. In that situation bring your camera as close to the barrier as possible, such as in between the links of the fence. This brings the fence or wall too close for the camera to focus on it, so it ignores it, and focuses on the real subject instead.

If you have manual focus available in your camera, there are times it’s the best focus method to use. For macro or close-up shots, night photography, portraits where I generally focus on the eyes, fireworks, low light or distant landscapes, I manually focus my camera.

A final thought. For many landscapes, I concentrate my focus on the foreground of my image, and let the focus be what it may for the rest of the photo. This is the way our eyes generally focus on outdoor scenes, and is a very natural look for landscapes, where the background focus is a bit soft.

¹Completely frustrated with a lens that was “back focusing” while traveling in Los Angeles in 2007, when reviewing photos taken earlier in the day, which had to be re-taken, I said, “Out of focus photographs give me a headache.”

1 comment:

Sam said...

Great follow up to Part 1 Ned.

I've got to admit, do I ever have egg on my face. I didn't know my Canon 790 had focus lock. Your article is going to revolutionize my photos. They are going to be sooooo much better now. Thanks so very much.

I'm going to recommend to all my friends they read your work every week, and sign up for your weekly newsletter so they know what you've been writing.

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