What is Selective Focus in Photography?
Selective focus is a method in which the focus is narrowed down to the focal point while leaving all other elements in the frame out-of-focus. Photographers do this by using a shallow depth-of-field or a small f-stop value.
Since our eyes are naturally drawn to objects that are in focus, using selective focus gives you great control over where to place your viewer’s attention. Selective Focus is also one of the most common ways photographers create the illusion of depth in a photograph.
How to Use Selective Focus in Photography?
1. Study Depth of Field
Understanding depth of field is key to using selective focus successfully. The depth of field is the section of your image that will be in sharp focus. It is the distance between the farthest and closest object in focus. Anything between those two objects will be in focus, while anything outside these two objects will be out of focus. The main factors the influence depth of field are aperture, focal length, and distance.
F-stops, or aperture, is the perhaps most common way photographers control depth of field. Using a high f-stop value will lead to a deep depth-of-field, while low f-stop values will lead to a shallow depth-of-field.
Because low f-stops yield a shallow depth-of-field using it means that a smaller portion of your frame will be in focus. For example, if you want to bring a person’s eyes in sharp focus but leave other facial features softly blurred, you can use a small aperture value such as f/2.8.
In contrast to low f-stops values, a high f-stop will keep a wide area of in your image in sharp focus. You can use any aperture higher than f/11 to bring most if not your entire frame into sharp focus.
2. Focal Length
Focal length also directly impacts the depth of field of your image. The focal length you use will shift your focal length closer or farther away from the camera. A longer focal length will produce a depth of field that is farther away from the camera. On the other hand, a short focal length will create a depth of field that is closer to the camera.
Your ability to selectively focus is inhibited by long lenses such as telephoto lenses. Telephoto lenses will allow you to place your depth of field and focus on an object that is far away.
Telephotos lenses with a wide focal range will give you the most flexibility when using selective focus. A telephoto lens with a fixed maximum aperture is ideal because it gives you greater control over the size of your depth of field.
Fixed telephoto lenses can be expensive; thus, an alternative is to opt for a lens with a variable maximum aperture. This means that as your focal length gets longer, your maximum aperture will get smaller.
To illustrate this point, consider the Nikon 18-200 mm f/3.5-f/5.6. At the shortest focal length of 18mm, the maximum aperture is f/3.5. While at the longest focal length of 200mm the maximum aperture is f/5.6.
Unfortunately, you’ll find that as you zoom in using a variable aperture telephoto lens your maximum aperture will continually release. Asa result, to maintain the same exposure at 18mm and 200mm you will need to adjust one of your other exposure settings.
That being said, you can use any lens to create a blurred background if the distance between the camera and your subject is workable. But, with long lenses, your subject will get further out of focus as you get closer to it. If you expand the amount of space between the background and your subject, you’ll also lose sharpness in your subject.
While it’s possible to work around these shortcomings to capture a great photo, a wide-angle lens will limit you in using selective focus. So, choose your lens strategically.
These three elements can all be used alone to alter your depth of field. For example, if you keep your distance from the subject and your focal length the same, you can lower your aperture setting to see an increase in your depth of field.
You can also work with these factors in combination to achieve your compositional goals. So, test out a variety of methods before settling on the best technique for your subject.
The distance between the camera and your subject also determines your depth of field. The distance is mainly affected by the focal length and lens that is being used. Each lens will have a minimum focus distance. This is the closest distance that the lens can focus.
In most cases, the longer the focal length the farther the minimum focus distance is. As a result, to focus on very close objects you will need a short focal length.
Furthermore, at each aperture and focal length combination, you will have a different range of your photo that is in focus. The focal length will determine how far or close that range is to your camera. The length of that range is determined by the aperture you are using.
For example, a Nikon 50mm f/1.8 lens set to f/4 with a focal point set 25 feet away will produce a depth of field that is 21 feet wide. The depth of field will start from 18 feet away from your camera and end 39 feet away from the camera. Any objects in-between this range will be in focus. Any objects outside of this range will be blurry and out of focus.
As a result, changing any distance, focal point, focal length, or aperture will alter the distance and range of the depth-of-field. For example, separating your subject from your background is a reliable method for achieving selective focus. To explore this method, consider the same scenario we gave above a Nikon 50mm f/1.8 mm lens set to f/4 with a subject 25 feet away. At these settings to separate your background, it will need to be more than 39 feet away. Anything beyond 39 feet will be blurry and out of focus while anything in the range from 18 feet to 39 feet will be in focus.
2. Use Extension Tubes
Telephoto lenses are expensive. A budget-friendly way to increase your focal length is by using an extension tube.
An extension tube is a cylinder that fastens between the lens and the body of your camera. This additional space allows you to increase your focal length without purchasing a new lens.
Extension tubes don’t hold any optical elements, but it does enable you to use a smaller focus distance than the lens alone would allow for. Since there isn’t any glass built into the tube, it won’t lower the quality of your shot.
Higher-end extension tubes can be stacked. So, you can use more than one extension tube at once to further extend your focal length. Using stackable extension tubes also allows you to hone in more closely to your subject, making for a smaller depth of field.
That said, note that extension tubes also lower the magnitude of light that can reach your camera’s sensor. For compositions that need more light, it’s often essential to increase the aperture.
Here are a few extension tubes I’d recommend.
3. Choose A Focal Point
The focal point of any shot using selective focus is critical to the entire composition. Your focal point will stand out more than usual, so you must choose one that is strong enough to carry the whole composition.
Once you’ve chosen a subject, try out a variety of focal points during the shoot. For instance, the shape of a flower’s petals could be the focal point of one image. Then, you could switch to focusing on the detailed, symmetrical stems of the flower instead.
It’s also helpful to pay attention to visual characteristics such as color, shape, texture. For example, if you’re shooting a tree branch, try to isolate its rough, intricate texture against the soft, blurred background. With this technique, you can shed light on certain qualities that viewers may not otherwise notice or appreciate.
4. Find The Ideal Background
Photographers often opt for selective focus when they’re working with an unappealing or chaotic background. In these circumstances, using selective focus can help you take successful shots despite a poor background.
That being said, your choice of background will impact your image, no matter how much you blur them. Thus so you should carefully choose what will appear in your background.
Choose a background that pairs well with your focal point. If you have a colorful, patterned, or otherwise visually striking main subject, a neutral background will make it pop.
If you have a heavily textured focal point, opt for a background with subtle, delicate details. Backgrounds such as a field of uniformly colored flowers, lush green leaves, or the ocean waves can add interest to your background without detracting from your main subject.
You’ll also want to avoid bright objects in your background. Bright objects, no matter how blurred, will pull your viewers’ focus away from your focal point.
5. Try Different Perspectives
When using selective focus, the subtlest change in the camera angle will have a huge impact on your image.
For example, when you’re photographing a human subject, you’ll likely want to place your focus on their eyes. However, if you position your camera in a way that your subject’s eyes are not on the same plane, the eye that’s a lesser distance from the camera will be clear and sharp, while the eye further from the camera will be somewhat blurry. This is true even if the difference in their distance is a single centimeter.
Another example is photographing people standing in line. If position your camera parallel to the line, the resulting image will be uniformly focused.
On the other hand, if you stand at a 30-degree angle relative to the line of people, only a handful of people closest to the camera will appear in sharp focus. The people towards the back of the line will appear blurry and out of focus. This is an example of how you can use selective focus to capture interesting images.
6. Set One Setting At A Time
You may feel like you’re juggling several elements when you use selective focus. After all, many factors go into using the technique.
The best way to tackle the complexity is to establish a plan before you set up your camera. Below are the steps I follow when using selective focus.
Your first step should be to decide on your focal point. Once you have decided on your focal point, choose a background to compliment or contrast your focal point.
Next, decide on the camera angle that produces the most compelling visual.
Finally, with the subject, background, and camera angle decided upon, you can make changes to your aperture, shutter speed, and ISO, accordingly.
7. Use Live View Mode
It is hard to predict what your depth of field and focus will look like when using a DSLR. Since DSLR viewfinders don’t automatically show the depth of a scene.
One way to overcome this issue is to use the live-view mode on your DSLR. In live-view mode, the LCD screen will display a preview of the scene as it would appear in an image.
This will allow you to see the focus and depth of field of your image without having to take and preview the image after changing your settings.
This means that as you adjust the depth of field in your image, you will be able to see the exact changes in live view mode. Using live-view mode is a more efficient way of checking your focus rather than taking an image and previewing each time you change your settings.
That said, it’s important to note that using a DSLRs LCD screen to preview depth-of-field won’t always work. For instance, if you’re under a bright sun, it can be hard to make out the preview on an LCD screen.
In this case, a mirrorless camera with an electronic viewfinder can give you a more accurate depiction of the shot you’re about to take. The electronic viewfinder of a mirrorless camera allows for live preview, unlike the optical viewfinder of a DSLR camera.
Mirrorless cameras make it easier to accurately place your depth of field and ensure your subject is sharp when using selective focus. Mirrorless cameras are extremely beneficial during harsh light conditions because the view will is not distorted by ambient light.
8. Use A Tripod
A stable tripod is crucial to your selective focus shoot. This is especially true when you want just a small portion of your image to be in focus. The stability that a tripod provides can help you achieve a remarkably sharp and precise focus.
Some photographers assume that by using super-fast shutter speeds, they can avoid camera shake. But, even minuscule changes are inevitable with a handheld camera and will impact the quality of your image.
Tripods also allow you to make small changes to your frame with great precision. With the camera secured in place, you can perfect its angle and positioning between shots.
Keep in mind that many outdoor shots using selective focus require you to position your camera close to the ground. So, a tripod that omits the middle leg is ideal.
One of my favorite tripods is the Manfrotto 190 Go! M-Series. This tripod is great for several reasons. First, it is super lightweight and made of a carbon fiber which makes it durable. The second reason is the extendable side arm gives me a range of angles and perspectives that are much harder to achieve with other tripods. Finally, the legs and adjustable nature of this tripod also makes it easy to get super low to the ground while still being able to easily take images with my camera.
9. Be Patient
Selective focus compositions take several small steps to get just right. Remember that each of these steps can dramatically impact your image, so it’s important that you don’t rush. Give each step its due time and don’t force any choices.
If you can’t find a focal point that you like right off the bat, pick up your camera, look through the viewfinder, and take a closer look around. Look for a visual that makes you stop and look closer.
Throughout the shooting process, don’t be afraid to make adjustments, both big and small. It’s never too late to stop, recompose yourself, shift your framing, or even pop on a new lens.
Allot time for trial and error, using your imagination to picture the composition ahead of time. As you practice more, the selective focus will become a more natural skill to implement.
Using selective focus is one of the best ways you can create depth in your image. It’s also s a great way to direct your viewers’ eyes to your focal point and keep a distracting background from ruining a composition. So, while using selective focus requires practice, it certainly worth your time and effort.