Ridiculously simple – incredibly effective

What does this app do? It displays Siemens Star and prevents your phone/tablet from going to stand-by. That’s not a whole lot you might say, but it’s an incredibly effective tool for checking focus. With one tap you’ve got a high-resolution Siemens Star at your fingertips. No bells and whistles, but a handy little app for camera operators, focus pullers and photographers. And the best part: It’s free!

If you’re a camera operator, focus puller, or photographer, you know how crucial it is to ensure that your subjects in frame are sharp and in focus. With the Focus Chart app, you’ll never have to frantically search for your physical focus chart again. Our app is simple, convenient, and easy to use, and it’s completely free!


Siemens Stars work by containing multiple spokes, each of which is an exact distance apart from the others, and meet only in the middle of the star. Due to a scientific phenomenon known as spurious resolution, a Siemens Star, when not under sharp focus, will contain optical blur, causing the black spokes to take the place of the white spokes, and vice versa. Under sharp focus, however, this phenomenon will not occur, and the center of the Siemens Star will be clear and crisp. Using this method, photographers and cinematographers can determine the focus of their cameras with ease, by ensuring that the centre of the Siemens Star is clear.


Focus charts can help you test your camera’s autofocus and check to see if your camera or lens has chromatic distortions. They are a valuable tool for getting the highest-quality work possible.


That’s why we’ve created a free app displaying a Siemens Star focus chart. Additionally, the Focus Chart app helps prevent your phone from going to sleep due to inactivity. With the Focus Chart app, a high-quality Siemens Star is one tap away.