Exercise Focal length and angle of view

I took the three not particularly exciting photos above with the focal lengths of 7.40 mm, 11.60mm and 88.80mm respectively.

As per the exercise I adjusted the lens so that the two views appeared equal in the middle photo through the view finder. According to the 35 mm focal length equivalent data for the middle photo I was slightly out from the standard view of 50 mm as it read 67 mm.

I realised too late from reading the exercise that I should have gone back to the view with printed photos to compare the result but unfortunately this was not possible. I have however learnt that with a focal length of 88.80mm in the third photograph and an aperture of F/5.6 that it was not possible to take a clear photo. I assume with the tree in the foreground the camera focused on that and the narrow depth of field did not allow the clock to be in focus.

The focal length obviously determines how much I can get in the frame. The shorter the focal lenght the greater the width of view and conversely the wider the focal length the greater the magnification so there is less in the shot.