Welcome to objc.io issue 21. This month is all about photos and the iPhone and iPad camera.

This is an important area for developers. The iPhone has become the most popular camera in the world, and for many people, the camera is the most loved feature of their smartphone.

We cover a wide range of topics. Starting with the foundations, Daniel explains how the camera in your iPhone works, and Oliver discusses some essential image formats and APIs.

Next, we have a section about the camera and photo library APIs. Matteo writes about capturing images with the camera, including the new manual controls in iOS 8. Saniul walks us through the new Photos framework, and Sam shows how to integrate our apps directly into the photo library via photo extensions.

Once you have captured an image, you will want to process it with optimum performance, and that often means filtering it on the GPU. The easiest way to do that is to use Core Image, which is covered by Warren. The next step is writing your own custom shaders for image processing. Many developers dread direct GPU programming, but Janie shows that it isn’t as hard as you might think. Brad then explains how you can use the same concepts to develop powerful computer vision algorithms. Finally, Engin introduces us to OpenCV, a very popular open-source library for computer vision.

In addition to all the contributors to this issue, we had a lot of help from Ole Begemann this month. He really pulled some strings to make this issue happen. Thanks Ole!

Best from Berlin,

Chris, Daniel, and Florian.