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What Is the Angular Field of View for an iPhone 13?
I don’t know about you, but my iPhone isn’t just for Snapchat and cat videos. Nope. Sometimes I also use it for physics — because I love physics (and Snapchat is sort of silly, but there are some awesome cat videos). I mean, with your iPhone (Android too) — it’s not just a super computer in your hands, it’s also a data collector with all the sensors it has.
But instead of looking at all the awesome sensors (magnetic field, gyroscope, accelerometer, barometer, microphone) I’m going to look at the camera. If you record video with the camera, you can use something like Tracker Video Analysis to get position-time data for the motion of an object. It’s pretty awesome (oh, I even have a book — Physics and Video Analysis).
One important step in video analysis is to set the scale of motion for a particular video frame. If there is a known object in the frame, you can use the real size to set the scale (how many pixel per meter). However, sometimes you know how far away something is but not how big it is. That’s where angular size comes in.
The angular size of an object (θ in radians) depends on the length of the object (L) and the distance from the camera to the object (r). Assuming the object is far away, then all parts will have the same distance. With that, we get the following relationship.
