Besides exposure, focus is the second most important part of the iPhone photography. Any technical difficulty with your photography is more or less acceptable for your viewers, except for focus. When your photo is out of focus, all the rest of your technical and creative efforts are for zero. Also, there is little you can do to salvage an ‘out of focus’ photograph. Learn to get your exposure and focus right first. The tech skill of creating focused photos should become almost your second nature.
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Degrees of sharpness
Focus and sharpness are similar terms and concepts. It all depends on how clear the details are in your finished photograph. You, as the photographer, will be the ultimate judge of focus and sharpness. Some photographers insist on full sharpness. Others intentionally leave the object ‘out of focus’ in the frame for an artistic result.
Two ways to focus your iPhone camera
Getting the camera to focus on a single focus point is simple. There are two simple ways to focus on the native iPhone camera:
1. Autofocus. All mobile camera devices have built-in autofocus (AF) systems. The iPhone and other major mobile cameras have accurate and dependable AF systems. All these systems rely on one or more ‘focus points’ to set focus. Apple doesn’t disclose the number of focus points for their iPhone cameras. In general, most mobile AF systems are set up to maintain optimum focus in the centre of the frame and less around the edges.
Tip: autofocus works better in bright light than in low light. And it works better in wide shots than in close-up shots.
2. Tap to focus. Tap on an area of the frame where you want it to be the central point of focus. If you want to lock your focus, press down the focus reticle until you see “AE/AF LOCK” on top of the frame.
Stay in focus on the retina display
The retina display can be a little deceiving when it comes to evaluating focus. If you are unsure whether your photo is in focus or not, this is what you can do:
- Open the photo up in the camera roll;
- Double tap or pinch zoom to look at the shot at a higher magnification;
- If the photo looks focused at a higher magnification, then move on. If not, try again.
This sounds repetitive, but it’s worth the effort for special shots you want full focus detail.
Depth of field
The iPhone and many other mobile cameras can only focus on a single point at a time. The area in front of and behind the single focus point is named as depth of field (DOF) and looks focused. The area that is out of the DOF looks blurry. The DOF is described as either shallow (not much) or deep (a lot). When shooting with your iPhone camera, you want to find out the primary focal point in the frame. Then use DOF techniques to stress or minimise the object.
Four factors that affect depth of field
The fun part is learning to control the depth of field. Generally speaking, with almost all cameras, four factors affect DOF. They are lens aperture, lens focal length, light levels and focusing distance. The iPhone cameras have a fixed lens aperture and a fixed lens focal length. So for shooting with your iPhone camera, you can adjust light levels and focusing distance.
Light levels in photography refer to how much light you have on the subject you shoot. When you shoot indoors at night, the chances are that your light level is low. When you shoot outdoors on a sunny day, your light level is high. The iPhone camera, in bright light, has a deep focus (where everything is in focus). If you want to get a shallow focus (where the subject is in focus and background is out of focus), you can shoot in low light.
In iPhone photography, focusing distance is the trick. Focusing distance is the distance from the lens to the subject. To get a sharp subject and the background (or foreground) out of focus, this is what you can do. Move your camera lens close to the object, and tap to focus on the object. If the object is in focus, the closer the distance is, the more blurry the background is likely to be. A shallow focus is more likely to happen if you are shooting in low light.
The way to control focus and depth of field is different for an iPhone than a DSLR. With a DSLR, you have more control. But the small iPhone lens is mighty in performance. The tiny lens is still able to deliver high-quality pictures.