Ever heard about the value angle?

Without diving into too much engineering stuff, the value angle is a computed parameter that has a strong influence on the design of a camera mount and hence of the whole system. But there is more. It also gives a glance about what can be made lens design wise and how far optical engineers can push the design. In one word: it expresses the potentiality of a camera system.

The idea behind it is that a larger value is generally speaking more advantageous and that it allows the design of lenses that provide a particularly high image quality. Oh, and it’s a concept invented by Fujifilm.

The formula for calculating the value angle is: 

ValueAngle = 2 × arctan ((2 × flange distance) / (mount diameter – sensor diagonal)) 

In a recent Fujifilm summit, the company introduced the concept of value angle to discuss the X System. And it turns out Canon has a real winner here with the EOS M system. If you have a look at the table below, you’ll see Canon’s EOS M mount ranks first when it comes to this very parameter, i.e. it has the most flexible lens mount (please note: “Kleinbild” means “full frame”).

If you want to learn more about, German site Profifoto has good introduction (Original | machine translated).

Canon EOS M mirrorless system:

America: B&H Photo, Adorama, Amazon USA, Amazon Canada, Canon Canada, Canon USA
Europe & UK: Amazon DE, Amazon UK, Amazon IT, Canon IT, WEX Photographic, Canon FR, Canon UK, Canon DE