Can I calculate FOV by measuring a photographed wall at different distances?

[asa!!]

Hi.thanks about my question on focal length.you were really helpful.Another question now about Field of view. I know that it is a angle showing a triangle.inside the area of the triangle any object can be photographed .a i right?i know tha it is not a scientific explanation iam just saying what i haveunderstood.

i have a camera. I do not know the focal length nor the frame size.i want to calculate the FOV.listen to what i thought.i did an experiment.i was taking photos of a wall withbricks soas to be able to calculate the size of the wall i was phtographing each time.at each phot i was changingthe distance between the camera and the wall. i imagined a equilateral triangle.the base is the size of the wall.the height is the distance between the camera and the wall. from there i calculated the tan of the half angle of thetriangle.then i found the half angle , multiplied it by two and i found the whole angle of the triangle. i think this is the FOV.am i right or i have done sillu things?thank you very much

 

[brewnog]

Sounds good to me asa, after a number of pints.

 

[asa!!]

i wrote it again because at the first message i had done many mistakes .sorry

Hi.thanks about my question on focal length.you were really helpful.Another question now about Field of view. I know that it is an angle showing on a triangle.inside the area of the triangle any object can be photographed .am i right?i know tha it is not a scientific explanation, i am just saying what i have understood.

i have a camera. I do not know the focal length nor the frame size.i want to calculate the FOV.listen to what i thought.i did an experiment.i was taking photos of a wall with bricks so as to be able to calculate the size of the wall i was phtographing each time (by measuring the number of bricks and multiplying with the length of the brick).at each photo i was changing the distance between the camera and the wall. i imagined a equilateral triangle.the base is the size of the wall.the height is the distance between the camera and the wall. from there i calculated the tangent of the half angle of the triangle.then i found the half angle , multiplied it by two and i found the whole angle of the triangle. i think this is the FOV.am i right or i have done silly things?thank you very much