Difference focal length but the same angle of view

[TsurTriger]

I noticed that some lenses have deference focal length but produce the same angle of view. I don't get how it is possible.
For example:
Schneider Apo - digitar 4.0/80 L produces AOV of 53deg
Schneider Apo - digitar 4.5/90 N also produces the same AOV
Schneider Apo - digitar 5.6/100 N the same also.

Rodenstock HR Digaron-W 5.6/90 produces AOV of 70deg.

How can it be possible?

 

[ErikKaffehr]

Hi,

AOV same but for what image circle or what format?

Diagonal, horisontal or vertical?

Best regards
Erik

I noticed that some lenses have deference focal length but produce the same angle of view. I don't get how it is possible.
For example:
Schneider Apo - digitar 4.0/80 L produces AOV of 53deg
Schneider Apo - digitar 4.5/90 N also produces the same AOV
Schneider Apo - digitar 5.6/100 N the same also.

Rodenstock HR Digaron-W 5.6/90 produces AOV of 70deg.

How can it be possible?

 

[TsurTriger]

You answer to my question.
That is tricky, I thought that might be a parameter that makes the difference, like IC but I don't was sure.
Yes, you are right. The AOV is related to the IC and not to "common" format.