How to Manage Exposure & Focus On Your iPhone Camera

| How-To

In this article, I am going to show you how to avoid getting those under- or over-exposed and out-of-focus photos you sometimes capture using the camera built into your device. I will refer to the iPhone 5 in this article, but much of what I cover can be done starting with the iPhone 4S running iOS 5 and later, and the iPad 2 and later, running iOS 6.

First, I'd like to point out that there are two types of technology readers. Those who want the quick-and-dirty solutions to problems they are trying to solve, and those who, like me, want to know WHY things happen, and WHY we solve problems the way we do. We learn by understanding, exploring and experimenting.

So I'll cut-to-the-chase and address the first type of reader.

There are two methods for controlling exposure and focus on an iPhone:

1. Setting the Focus and Exposure: Tap once on an image to have the camera focus and set the appropriate exposure for that spot. This couldn't be any simpler. If photographing a flower, for example, tap on the flower (not a touch-and-hold). You will see a light-blue square reticle appear where you tapped. It will pulsate briefly until focus is acquired. Take your shot.

The AE/AF Lock indicator at the bottom of the image.

This indicates that you have successfully locked the exposure and focus.

2. Locking the Focus and Exposure: Press-and-hold (not just a tap) on an image to lock both the auto-focus and auto-exposure at the spot where you pressed; on the flower, for example. This can be anywhere on the image. The square reticle will pulsate a bit more vigorously, and an AE/AF Lock indicator appears on the bottom of your screen. When the pulsating stops, you can release. The focus and exposure settings are now LOCKED until you tap the screen again. I consider this an advanced feature. It's enormously useful in many situations as you can now recompose without affecting your settings. Take your shot.

As an aside, but related, if you see one or more green rectangles on the screen when you initially begin composing your shot, you are witnessing the Facial Recognition technology in action. Up to ten faces (including humans, dolls, some animals, and an occasional alien or two) will be recognized. Availing yourself of either of the two options above will cancel the facial recognition.

An iPhone screen capture showing how the Facial Recognition feature works.

Found faces are outlined in green.

That's it! Article done. Go shoot some pictures. See you next week.

Still here? You must be that latter type of reader. You know… the one who has a thirst for knowledge. Perhaps you are avidly interested in iPhone photography – a.k.a. iPhoneography. My kind of reader! Please continue…

An antique Kodak Instamatic film camera.

A classic - the Kodak Instamatic 100 film camera.

There was a time when the general population had access to a real simple film camera called the Kodak Instamatic. This mass-produced pocket camera was permanently configured in such a way that, as long as there was an abundance of suitable lighting, shooting a decent photograph was a sure bet. There were no concerns about fiddling with the camera's aperture settings and shutter speed. The camera didn't even require manual focusing.

On the other hand, more advanced point-and-shoot film and digital cameras could automatically vary settings to let its owner capture technically better shots, particularly in tricky lighting situations and difficult focus scenarios. Sometimes photo enthusiasts had a desire to exploit their photographic creativity and could manually alter camera settings. Among other things, this would allow them to experiment with selective focus techniques as well as manage tricky lighting situations such as backlit subjects and contrasty outdoor scenes in bright sunlight. People had the freedom to switch the camera out of its Auto-Everything mode and tweak the settings to get the perfect shot.

Enter iPhone, sporting a fairly decent camera – improving with every revision – and hundreds of photo editing and photo-novelty apps available for it. Many will disagree with the following statement: the iPhone revolutionized photography.

Picture of an iPhone showing an image of happy people using their iPhone cameras.

Everybody loves to take pictures with their iPhone cameras.

An entire industry has evolved thanks to iPhoneography. A resurgence of interest in photography has been stimulated thanks to online services in support of apps like Hipstamatic and Instagram, direct online photo printing and mailing services, international iPhoneography exhibits and competitions, as well as a plethora of iPhoneography courses everywhere. The quality of the images aside, iPhoneography has pioneered social interaction via the sharing of images.

The original iPhone was just like the old Instamatic camera. We had no control over the result, except for developing an eye for good composition, of course. The iPhone camera just captured the image while allowing no opportunity to change settings except for subtle adjustments to automatic shutter speed and ISO sensitivity. We didn't have to set any focus or exposure.

Snap! With the synthesized sound of the shutter releasing, the end-result was a fairly decent photo, as long as there was no tricky lighting or movement in the scene.

And then, there was this popular saying conceived by iPhoneographer Chase Jarvis: "The Best Camera Is the One That's With You." You see and hear this mentioned a lot on many photo forums and podcasts. But what does the expression really mean?

To me, the fundamental idea is this:  it doesn't matter what kind of camera you have. The number of megapixels it boasts, how many lenses you have, how many gadgets you can buy for it – none of this matters! For general photography, even "artistic" photography, it's not really about the camera brand, capabilities, specifications, and miscellaneous camera gear. It's about what's behind the camera: You – The Photographer! With a basic understanding of photographic composition and an eye towards good quality lighting, but most of all, a complete understanding of your camera's workings and its idiosyncrasies – no matter how simple – ANY camera can produce award-winning images for you.

The iPhone camera has matured just as the Instamatic evolved to automatic and semi-automatic point-and-shoot cameras. We are now given so much more flexibility if we want it. We can tell the camera by way of a simple tap of the screen exactly where to base its exposure in the scene we're capturing. This is vital for a successful image taken in tricky lighting conditions.

Additionally, we are now able to control where the camera will produce the sharpest focus for us. Depth-of-field (defined as the area in an image that is in acceptably sharp focus) is fairly deep to begin with because of the small size of the sensor, lens characteristics, and other factors. However, you can guarantee that the closeup of the flower that's in the foreground will be tack-sharp and that the background will be softer. This is called Selective Focus. It's a technique used by savvy shooters as a way to direct the viewer's eye to the subject in the image.

When you're setting up your shot, iPhone will always activate facial recognition first or the auto-focus point along with the auto exposure. By default, this happens smack-dab in the center of the image without you doing anything except watching. This is indicated by the momentary appearance of a light-blue square reticle in the center. The problem is, if you recompose your shot, the auto-focus and auto-exposure setting will change accordingly to the "new center" of the recomposed image. You can clearly observe this. It's fine for the typical snap shooter where everything needs to be centered. But this is often booorriiing… You're not the typical snap shooter, are you?

What if you want to focus and set exposure on your subject, then place it more off to the side of the image for a more pleasing composition (following the "rule of thirds")? The problem is that if you have acquired accurate focus and exposure on a perfectly centered subject, then you recompose the shot, the camera will refocus and set the exposure for whatever ends up being there after recomposing. It could be a very bright area far away, leaving you with your subject out-of-focus and somewhat underexposed. This is a typical problem, even with point-and-shoot as well as DSLR cameras, unless you know how to override this default behavior.

A photo taken with an iPhone that shows how focus is set in the center by default, but that may not be what we want.

Focus and exposure are set in the center by default, but often that's not what we want as the subject is not always in the center of the image.

Starting with iPhone 4S, Apple has given us the solution. We can now manually set the focus and exposure settings for the purposes of producing more creative photography in the form of selective focus as well as targeted exposure in tricky lighting conditions.

To wrap-up this aspect of iPhone photography – because there is so much more to discover – let's use a typical example to illustrate what I have covered in this article.

Let's say you want a nicely composed photo of a flower in an outdoor garden setting. It's a bright day as the sky is filled with large white clouds. There is also a white wall from a nearby building. Since the flower is the intended subject, it must be properly exposed, in sharp focus, and off to one side for a pleasing composition. The rest of the garden, the wall, and the bright sky are in the background. This is the often-dreaded backlight scenario. By backlight, I mean: an area of brightness behind the subject, such as bright sky or a white wall. Often, little or no subject details are discernible due to the overabundance of brightness behind it.

Photo taken by iPhone where the exposure and focus was based on the bright sky, causing everything else to become underexposed.

When exposing for the bright sky, the entire picture underexposes, and detail in our subject is completely lost and out-of-focus.

iPhone's built-in camera software measures the amount of light that passes through the lens; a digital light meter. It will be fooled into underexposing the scene because a camera typically wants the entire image to be as close to a neutral tone as possible (equivalent to an "18% gray reflectance", in photography parlance). So, if there is a large bright area – the white clouds and wall in our example – then the entire image tends to be underexposed and ends up having an overall muddy appearance.

Since our intended subject is the flower, we want our viewer to see its bright, colorful details in the finished photo, just as our eyes originally saw them. The bright sky and wall are irrelevant. They would simply be distracting elements. Of course, you could simply crop the offending sections out – and that may be the best solution – but it would defeat the purpose of explaining this aspect of iPhoneography. How do we tell our iPhone camera to set the exposure properly in order to render the flower as we desire, at the expense of everything else in the photo? Additionally, we want the flower to be in sharp focus. Question is: won't iPhone reset the focus and exposure points wen we recompose the image?

Same photo as before, but now properly exposed and focused for our subject, while the bright background gets overexposed.

By tap-and-holding on our subject, we can ensure that it will be properly exposed and in focus.

By utilizing the second technique described at the beginning of this article – Locking the Focus and Exposure – you will actually see the flower "bloom" to its natural colors and brightness, while that relatively unimportant background becomes overexposed. Many times in tricky lighting, you have to either sacrifice details in the brighter image highlights or details in the darker shadows – depending on the placement of your subject.

iPhone's camera software has a feature called HDR (High Dynamic Range), a technology that helps deal with these high differences in image contrast. This is something to examine in other and future articles here on The Mac Observer.

In conclusion, by understanding the built-in capabilities of your iPhone's camera, as well as the the many excellent third-party apps that provide enhanced control of the camera, you will find many creative opportunities for you to pursue your photographic vision using... the camera that's always with you.

Comments

Lee Dronick

Sandro, this an excellent article and I will link to it from my Facebook page.

Paul

Great article. I appreciated the refresher.

Veronika M

I have had my iPhone for almost 2 years and never knew that you could set focus or exposure this way.  Thank you!  I will use the built-in camera so much more now.

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