As I understand it - not at all. That is set by the eyepiece geometry More knowledgeable ones will know more...
For the earlier point.
Pupil exit size X Focal ratio = eyepice size or
Pupil exit size = eyepiece / Focal ratio
so for a .5mm exit pupil with an F4 scope barlowed (X2) to F8 gives an eyepiece of 4mm minimum size.
True FOV is the smaller of that given by the Aparent field of view or that limited by the field stop.
AFOV = eypiece field of view (approx 50 degrees for plossls) / magnification where magnification = focal length / eyepiece size.
also Focal length = Aperture X Focal ratio
TFOV = (field stop diameter/Focal length) x 57 degrees (approx)
so a 1.25" eyepiece with a maximum practical field stop of 28mm in a 4.5" (114mm) F4 scope barlowed (x2) has a TFOV of
[28/(114X4X2)]x57 = 1.75 degrees (maximum), and a 4 mm plossl gives a FOV of 50/[(114x4x2)/4] = 0.22 degrees or 13 minutes. a 40mm eyepiece (if there were such a 1.25") gives a FOV of 2.2 degrees capped at 1.75 degrees as noted above.
Maybe this helps