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Simple Photo Tips: Tap to focus

5
One of the keys to creating a successful photograph lies in making sure that your main subject is in focus.

While many shooters are happy to leave focus selection entirely up their camera, experienced shooters know that you can get more creative and predictable results by making that decision yourself. And with a smartphone camera it couldn't be simpler to do.

Using the built-in camera app on either an Android device (running 4.0 or later) or a recent iPhone, just tap the screen to specify where the camera should acquire focus. An autofocus square will appear for a moment onscreen at the location you tapped. And you can see that region of the image suddenly snap into focus.

It's important to realize though, that as well as focus, you're probably also telling the camera where to take its light reading from. So don't be surprised if you see a difference in the brightness between images taken with focus set on different points. You can see this demonstrated in the examples below. Click through for full size versions that make focus differences easier to judge.

Tapping on the flower in the foreground sets focus there as well as exposure. Notice that the more brightly lit rear wall is overexposed.
You can shift focus and exposure by tapping on the rear wall, instead. Notice this leads to a darker exposure which holds detail in the wall.

You should know that if the scene objects are more than a couple of feet away from your cellphone your main subject will probably be in focus wherever you set the focussing point. Smartphone cameras have a very wide area of simultaneous focus (known as depth of field). In fact, you may find that this "tap to focus" technique actually comes in handy more often as a tool to quickly set exposure (scene brightness).

This technique can also be helpful if your camera cannot seem to lock focus on a low-contrast object (like an evenly lit backdrop). Just tap on a higher-contrast object of similar brightness to give your camera something easier to lock onto.

Using a tap to set focus and/or exposure adds just one brief step to your picture-taking routine yet allows you to come away with more professional results. Give it a try and impose more creative control on your photography.

Comments

Total comments: 5
aneeshanand

Camera 360 gives option to tap and focus, shake free etc.

0 upvotes
Doug Pardee

Multiple metering and focus areas weren't introduced into Android until 4.0 (Ice Cream Sandwich, API level 14). I suppose it's possible that some camera apps found a way to do it anyway on earlier versions, but I doubt it. In general, Android users need ICS or later in order to select focus/exposure areas.

Also, the number and positions of focus/exposure areas in Android is variable. And in Android, at least, zooming makes it easier to select a precise focus/exposure area, because the areas are positioned relative to the displayed image on the screen.

2 upvotes
Amadou Diallo

Great points, Doug. Thanks for sharing them. I've updated the article to indicate v4.0 or later.

0 upvotes
almusik

My Galaxy S with Gingerbread (2.3.3) allows the selection of focus and exposure areas

0 upvotes
Ryan Williams

The Galaxy S comes with Samsung's own modified version of Android, and doesn't use the default camera app Android ships with. It's possible Samsung hacked in this functionality before it was a general Android feature.

1 upvote
Total comments: 5
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