Jul 13, 2008—How do you know when a photo is in focus? I’ve examined hundreds of thousands of dog pictures in the last year and a half, and I have some suggestions for you.

These suggestions pertain to viewing full-resolution files on a good-quality computer screen. I typically view the files at a 1:1 ratio in Adobe Lightroom on a 20-inch screen, where they are many times larger than the original 35mm images. That’s the equivalent of viewing a 35mm image enlarged to a 20 in. x 30 in. print.

These suggestions are generally in top-down order. The first suggestion below is the most important one, and so on.

- The eyes have it. The first place I look is at the dog’s eyes. If the eyes look what I call “water clear,” then the most important part of the image is in focus. My term “water clear” means that there is a clearly defined highlight (or highlights) in the eye, the eye has the shine of water, and the edge of the eye is clearly defined.

- What sharp teeth you have! In some images, the dog’s mouth is more noticeable than the eyes—especially true for dogs with lots of facial hair, like bearded collies. In that case, I look for clear, sharp teeth and visible whiskers. If I can see those things, then the most important part of the image is in focus.

- Winning by a nose. Another important area of focus is the “nose leather,” which is often damp and shiny. If the nose has a clearly defined area of highlight (or highlights), then that part of the image is sharp.

- Let the blur take the hindquarters? So if one or more of those important facial features is in focus, what if the rest of the dog is fuzzy?

Well, in all photography, there is only one area that’s in perfectly sharp focus, and that is an imaginary plane (flat surface) that is in front of the lens and perpendicular to it, at a defined distance from a certain point inside the lens. In indoor action photography, which is almost always shot with available light (no flash or studio lights), the depth of focus can be very “shallow.” That is, a dog that is a few inches further away or an inch or two closer may not be in focus. In photography done in bright daylight or with flash and studio lights, the depth of focus can be “deeper.” That is, the area of focus may be several inches to several feet thick.

The settings on the lens also affect focus. The lens can be used either wide open or narrowed—“stopped down” by defined points called f/stops. Having the lens stopped down gives an effect like squinting with our eyes: It makes a previously unclear image look clearer. That’s because the narrower lens opening increases the depth of focus.

What all these factors mean—the eyes, teeth, nose, and hindquarters—is that having the important part of the face in focus is often the best that action photography can deliver. After all, your dog is in motion. It basically makes sense that the hind legs are blurry when the face is sharp. Whether a blurry hind end is acceptable is really up to you.

- The zoom test. When you’re comparing two similar images, the final test can be to zoom in on both of them and scrutinize the focus. Examine the eyes closely. Are the highlights sharp? Apply the “every hair” test—can you see every hair or every whisker? Check out the nose leather. Does it look shiny and damp? If you see that one image is, in fact, clearer than the other, that may be the deciding factor.

Of course, sharpness may not be the only factor to consider in choosing images. For other suggestions, see my article on choosing agility photos.

- Examples. Check out the examples below. For these shots, Virgil focused on a point just ahead of the jump and held the focus there. It was the point where the dog’s position would make an ideal composition. As the examples show, just a few inches of difference in the dog’s position makes a considerable difference to the clarity of the image.

In the top left image, the dog’s face is in the plane of focus. Look at the clear bright eyes, the crisp whiskers, and the defined nose leather. The top right image is a close-up showing the focus in greater detail.

In the bottom left image, taken just a few inches later, all elements of the dog’s face are soft or blurry. As the close-up shows on the bottom right, the real focus is behind the collar, where every wisp of hair is visible.

Of course, in both of these images, the dog’s back and hind legs are blurry. Again, that’s to be expected when a running or jumping dog is photographed indoors with typical shallow depth of focus.

To see these effects most clearly, click on Start Slideshow.

- The eye of the beholder. What it comes down to is that acceptable focus is largely in the eyes of the beholder. For a variety of reasons, you may be satisfied with images that Virgil or I would discard. Reasons can be emotional—you like seeing how high your dog can jump, you’re glad to see your dog running confidently after surgery, or you like the funny way your dog’s tongue is hanging out. Or they can relate to information—you finally see in the photo how your body language is causing your dog to go the wrong way.

When Virgil or I discourage you from buying images that are less than sharp, we’re doing that because customers in the past have loved a blurry image while they bought it, only to decide later that it wasn’t good enough. We don’t want that to happen in your case. But if you fully understand the condition of the image and still want it, we will honor your request.

For the last article in this series, Indoor Action Shooting Tips, click here.

Virgil welcomes questions about cameras, lenses, software, etc. If you have questions, send him an email or talk to him at a future event.