Taking a picture by different camera and lens, yet preserving same angle...not uncommon situation in commercial photography world. You might have to calculate lens size whenever you encounter the situation.
Lens Exchange set you free from calculating again and again in the situation. You just select preset imaging area and lens size, Lens Exchange tells you the lens you should use to take an equivalent angle for the different imaging area and shows you the comparison of imaging areas by diagram. Of course you can add the your own preset.