Focus, overcoming the "fuzzies" Part 2

In 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.”

Utilizing 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.

For 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.

Sometimes, 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.”

Focus, overcoming the "fuzzies" Part 1

Ansel Adams said, “There is nothing worse than a brilliant image of a fuzzy concept.” While I certainly agree with Adams’ sentiment, if your photo is out of focus, no one will care about your image.

Today’s digital cameras, whether expensive DSLRs or low end Point & Shoots all have remarkably accurate automatic focus capability, but sometimes, your image composition, or conditions which are a bit out of the ordinary, can defeat any camera’s auto-focus.

In Part 1, I discuss 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.

In auto-focus, the camera senses the difference in contrast between the edges of objects as seen through the lens. When the subject has sharp contrast differences, the camera will probably easily and correctly focus. If the edges of your subject are fuzzy, or aren’t clearly distinguishable from the surrounding background, the camera will have difficultly focusing, if it can at all. When this occurs, the camera’s auto-focus system will keep searching to find a clear sharp edge. This is sometimes called hunting.

Usually, in brightly lit conditions where the subject’s color makes it stand out from the background, auto-focus has little problem. If the light is dim, or the subject is similar in color to the background then auto-focus probably won’t work. Likewise, if your subject has multiple line patterns, it may have too many edges and the auto-focus system may not be able to decide on one to use, and therefore hunt. The same thing happens when there are many objects in the focus area.

Recently, at a forum I frequent, a photog new to his DSLR told us how he tried to take a photo of a coyote about 100 yards away. He was trying to understand why his photograph was out of focus. The problem was the image was monochromatic, with the coyote blending into the background. In addition, in the overall landscape the coyote wasn’t much more than a blip. The camera’s auto-focus really didn’t have a chance. The photog needed to manually focus in this situation.

Auto-focus has a number of methods or modes it uses to determine at what distance from the camera it should focus the lens to produce a sharp image. The modes have different names, according to the type of camera and brand. I’ll briefly discuss the major modes.

Face Detect:

The camera automatically detects the location of faces in the photo and focuses on them. If you’re taking a photograph of a single individual, or a small group of individuals in a single row, or “scrunched” together, I’ve found this mode works exceedingly well, especially on newer cameras.

The mode has difficulty when you’re photographing people of different complexions, and large groups in multiple rows or at tables, as they depend on depth of field and the photographer doesn’t control the actual point of focus.

Dynamic Area (No Frame):

The camera uses information from multiple focus points in a specific area of the image to determine focus. This mode is especially suited to continuous focusing, for action photographs. In this mode, the camera gets to choose the primary focus point in the focus area, not the photographer, which can be a problem.

Group Dynamic:

This mode is similar to the Dynamic Area mode. It uses multiple focus points in a specific area of the image to determine focus, but unlike Dynamic Area focus, the photographer chooses the primary focus point within the focus area. This mode is especially suited to continuous focusing, when shooting action photographs.

Closest Subject Priority:

In this mode the camera focuses on the closest object of significant size in the image. The problem with this mode is when the closest subject is not the main subject and the camera focuses on the wrong part of the image. I never recommend this mode.

Single Area:

In this mode, the photographer chooses which focus point among all the available focus points for the camera to set the focus. In some cameras, it’s always the center focus point. This is an excellent mode for portraits or any photograph in which your subject(s) are stationary.

For many amateur photographers, Face Detect mode can be extremely helpful in taking photographs of groups, as long as you understand its shortcomings.

I never utilize Dynamic Area focus due to its uncertainty, but do use its cousin, Group Dynamic focus, when I’m using continuous focusing for action photographs.

For stationary subjects, I use Single Area mode, and use the focus point which matches the location of where I want to focus in the photograph, or I use the center focus point (more often than not), focus, then recompose my image to get the precise composition of the image I desire.

Part 2 next week.