Years ago, my family hosted a foreign exchange student from Ecuador. Once while riding in the car he told my mom to “focus on the road”, but his pronunciation of the Oh in focus, sounded more like an Uh… I’ll pause while you say this aloud to yourself and laugh. He was rather embarrassed to learn what it sounded like he was saying and it has been a funny story in our family since. In photography, making sure you are focused is a must, but with modern cameras there can be some unintended consequences.
The first part of this post is primarily written for all the cell phone photographers out there, but the premise applies to traditional cameras as well, more on that later. Modern phone cameras are built to be as user friendly as possible. This can be limiting, but knowing how they are designed to perform allows you to get the most out of them. I hope this article helps you with some tools to make you a better photographer.
In traditional photography, focus is a component that is independent of exposure. Focusing a lens has come a long way with the advent of electronics, especially auto-focus. Modern phone cameras generally only have two modes of auto-focus; full auto and tap-to-focus. If you take a picture, without tapping to focus, the software in the app surveys the scene and attempts to determine where the majority of the picture will be in focus. I generally advice people to not to let the camera make decisions that are easy for you to make, especially when the solution is as easy as tapping the screen. But there is a more technical reason to make sure you focus the lens. Phone cameras have a fixed aperture, which controls the depth of field (whats in focus). Counting on all of your photo to be in focus based on your camera selecting the focal point is not a good idea. It it may look like your subject is within the depth of field, but you might as well take the time to tap and get it right. See the example below if you don’t believe me.
That being said, there are always exceptions to the rule. An example is when the entirety of the photo is on the same plane, i.e. document photos, subjects that take up most of the frame, and distant landscapes with nothing in the foreground. But even in those cases, tapping the screen doesn’t hurt.
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Most of you probably have a pretty good handle on ‘tap-to-focus’, it’s so intuitive that even some DSLR cameras are adding the function to the display screens. But I wanted to touch on a potential unintended consequence. In order to make the camera operation as simple as possible, the software engineers have lumped in another component of photography in the tap-to-focus operation called the acceptable exposure limit. This is how the camera calculates the exposure to determine how light or dark your photo will be. Like the focus function, if you don’t tap the screen, the app analyzes the scene and determines the best shutter speed and ISO to make an acceptable exposure. Most likely you have experienced this when you point the camera up at a bright sky causing the foreground to get dark, and as you lower the camera back to the foreground, the sky becomes blown out, or white. When you tap-to-focus, the camera recognizes that spot as the subject, changing the focus and exposure to make sure that spot is exposed “correctly”. This can have drastic affects. A classic example is a bright sky behind your shaded subject. If you tap on the subject, the deep colors of the sky get washed out. Contrarily if you tap on the sky, the subject becomes dark (not to mention out of focus!). In the example below (left), the blue sky is washed out to white, but the tree trunk (where I want the focus point) is exposed properly. These are examples of when you don’t want your focal point to be the place to measure the exposure level (a more drastic example would be a true silhouette, where you want the black area to be the focal point for nice crisp edges). In order to give you some control in this situation, phone cameras have included an exposure adjustment bar. It shows up after you tap to focus and you can slide the exposure bar to brighten or darken the photo to your expressive desire, while maintaining the focus at the point you tapped. In the scenario of the bright sky, you can now focus on your subject, and slide the bar down, recovering more of those amazing colors in the highlight areas.
Right now, you might be thinking, why can’t I have my cake and eat it too? Why can’t the camera capture both the highlights and the shadows?… just to be mean, I am going to answer that in an upcoming post, so stay tuned.
If you are still not getting the photo you want, and the foreground is too dark or the sky too bright, there are two things you can try doing… first is a fill flash. If you subject is close enough, try turning on the flash, tap to focus on your subject, bring the brightness down, and let the flash brighten up your subject in the foreground (warning, phone camera flashes are pretty weak). A second more complicated alternative is to fix it in post production. After taking a picture, go to your preferred editing app (I use Snapseed), and use it to brighten up the shadows and/or darken the highlights. One tip on this would be to generally err on the dark side, it’s much easier to pick up details in the shadows than in the highlights. I have done this in the picture of the tree below. Please comment below if you would like me to include a video tutorial on this in the future.
NERD ALERT: If you are a phone only photographer, you can stop reading, but don’t do something just cause I told you to.
How does this concept affect cameras with more functions? Most modern cameras have auto-focus area modes, where you can choose where the camera looks for a focal point. For general use, you can use the wide mode, which like the phone camera, will survey the entire scene. Other modes include: Center focus, which will only look in the center of the frame for the subject. Spot focus, where the user can move the focus box around the camera to choose where to look (similar to tap-to-focus), and some even come with tap-to-focus. Different camera makers call them different names, but flip through them to know what your camera is capable of in controlling the focus area. I generally use spot focus to make sure I am accurate with my focus, but use other modes depending on the situation. Here’s a video showing the focus modes of my Sony A7II.
Additionally, like phone cameras, the default mode of most cameras assume that you want your exposure to be measured at your focus point. (I won’t go into metering modes here, please comment below if you’d like to see a post on that). Some cameras have an equivalent for the exposure slider in phone cameras. The exposure compensation dial is indicated by a range of values, typically -3 -2 -1 0 +1 +2 +3 (Shown in the picture below). If you are in a mode where the camera is calculating the exposure (anything except manual) this dial allows you to brighten or darken a photo manually, while maintaining your focus point. There is another way to control the exposure that some photographers like, and that is the AEL lock button, or acceptable exposure limit (Shown in the picture below). To use this, you can position the camera towards the area that you want exposed for, in our previous example it would be the blue sky, hold the AEL button, re-frame you photo and focus on your subject, and release the shutter. Your camera will not correct the exposure but will focus the lens. This is a pretty advanced move, however, once mastered it can really transform your control over focusing and exposure.
I hope this helps you better understand the effect focus can have on your photographs with modern equipment. Just remember, always tap to focus and adjust the exposure slider as needed.