Google Camera app simulates lens blur on camera phones
By Loz Blain
April 17, 2014
Google’s new Camera app for Android aims to address one of the greatest advantages that big-sensor, big-pricetag DSLR cameras have over phone cameras – the ability to blur out the background and achieve a bokeh effect. What’s more, this clever piece of software allows you to choose your point of focus and amount of lens blur after taking the shot. Very cool.
The convenience and quality of modern camera phones is starting to make the compact camera completely redundant. One thing that large-sensor DSLRs still have over camera phones is the ability to produce shallow depth of field, which results in a blurred background or bokeh effect.
To get a really nicely blurred background with a sharp subject, ideally you’d be using a very expensive full frame or medium format SLR camera, with a very expensive wide aperture (f/2.0 or lower) telephoto lens.
To achieve a similar effect using the tiny lens and sensor of a camera phone, your only real option is to use macro mode on tiny subjects.
That’s what makes this innovation from Google so interesting. Using brains to emulate the brawn of an expensive camera, the Google Camera app for Android phones has been updated to include a "lens blur" feature that simulates a wide aperture effect, and allows the snapper to choose what to focus on, and how much to blur the background, after the shot has been taken.
The way it achieves this is fascinating in itself. Instead of taking a single photo, you sweep the phone upwards and take a series of shots. The phone then compares these shots to find the location of objects as the camera moves – provided the scene is kept still, closer objects should move more in the frame, and further ones will move less, in the same parallax effect you can see looking out your side windows on a highway.
A number of other calculations are performed to develop a depth map for the scene in which each point has a triangulated 3D position. Then it’s a relatively simple matter of choosing a focal point, and applying a blur filter to each other point in the photo that increases the further away from the focal point it gets.
Considering it’s a software solution to what’s really a hardware problem, it doesn’t do a bad job within its parameters. At the end of the day, it’s a very clever way of achieving a Lytro-style post-shot focusing effect.
The new Google Camera app works on all phones and tablets that run Android 4.4+ KitKat.