I am using two lenses: Tamron 75-250mm F / 3.8-4.5 Model 104A and AF-P DX NIKKOR 70-300mm.
When shooting with lenses set at 250 mm focal length, the field of view of the Tamron lens is larger than the Nikkor lens. The camera used was Nikon D5200 with a sensor size of 23.5mm X 15.6mm.
It is commonly understood that the focal distance decides the field of vision (similar discussion in this forum), but here is a case in which the field of view is different in different lens models with an identical focal length.
Here is an image of a scale / ruler with marks taken with both lenses from a distance of 3 m.
How can this be explained?