How to focus a photo after you’ve taken it

Taking a photo only to discover your main subject is out of focus is a common and frustrating problem. It’s okay if you can simply take the photo again, but what if the moment you captured was fleeting, or you don’t notice the issue until you get home?

If you own a Lytro camera, you’ll never experience this heartache again. Clever light field technology means you can refocus your photos – and even change the perspective – after you’ve taken them. It does this by using a microlens array and a special light field sensor to determine from which direction rays of light enter the camera. This allows it to record a multidimensional light field, which is passed through special software.

Complex algorithms are then able to simulate what the image would look like if you had focused on a different focal plane or taken it from a different angle and all of these possibilities are pieced together to create one adjustable image. Light field technology isn’t new, but Lytro is the first to use it in a commercial camera. Its latest model is the Lytro Illum, which has an 8x optical zoom lens, ten-centimetre (four-inch) LCD screen and can shoot 3D images too.

Light field photography

Light field photography

Refocusing images

Lytro test shot

If the main subject of your photo is out of focus…

Lytro test shot

…just tap or click it on screen to bring it into focus

Once you’ve taken your photo, all you need to do is tap the out-of-focus area of the image on the camera’s touchscreen and it will instantly become sharp, or swipe over the image to adjust the perspective. You can even change your mind about the angle and focus by tapping and swiping as many times as you like. When you take the image off of the camera, it will be saved as a Light Field Picture (.lfp) file, which will contain all of the light field information. To view it you will need Lytro’s free desktop or mobile app, which allows you to click and drag to adjust your shot and share it online. If you share your photo through Lytro’s online platform, your friends will be able to adjust it too, but if you convert the image to a .jpg file then it will become a normal, unchangeable digital photo.




Discover more amazing technology in the latest issue of How It Works. It’s available from all good retailers, or you can order it online from the ImagineShop. If you have a tablet or smartphone, you can also download the digital version onto your iOS or Android device. To make sure you never miss an issue of How It Works magazine, make sure you subscribe today!

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