TerryMiller wrote in post #17365636
Zack did a pretty good job of explaining it. Start by putting your softbox 2 feet away from the subject, then 3, then 4, then 6 and watch the explanation again with your photos to look at.
Better still, do the same thing but have your light at 2ft, 2.8ft (2'9½"), 4ft, 5.6ft (5'7¼"), 8ft, 11ft and even 16ft if you can manage.
Existe uma relação direta entre a distância, luz cair e abertura.
A shadow is always positioned exactly on the extended line from light source through subject, on the side away from the light source.
The SIZE of the shadow is very little to do with the physical size of the light source but everything to do with the APPARENT size of the light. Stand facing a mirror with your hand out-stretched so it nearly touches the mirror. The hand appears MUCH bigger than your head. Now, without moving your feet, put your hand next to your head and it appears smaller than your head. All that has changed is the APPARENT size of the hand, controlled by relative distances.
Hence a large softbox will give you a smaller shadow than a small softbox would at the same distance. Conversely, if you had a very small light source really close to the subject, you could get a massive shadow.