Anthony Pittarelli

I don’t know if I could clearly explain why this would be.

Perhaps the influence of other lights (and shadows) raise the background ‘noise’ level, so to speak, and so make your shadows edges less sharp.

However, this would mean that if there are no other light sources, then it would always stay sharp, and I don’t think this is the case.

Perhaps the edges of the form are not sharp at a microscopic scale, and so they make the light diffuse around the corners. This is not obvious when the shadow is case close to the object, but becomes obvious when it is further away.

So the shadow is still sharp near your feet, even when you are far from the light, but it is blurry around your head.

I thought it might have something to do on whether the light was being seen as a point source or a diffuse source of light, and this may have an effect in some situations. However, the light would seem more point-like when you were further away, which I think would make it sharper, rather than fuzzier.

Also, you see the same effect on the sun shining through trees (I think). The shadow is sharp when the object is close to the ground, and fuzzy when it isn’t.

it does this because you are walking out from under it so your shadow also moves out from under you. Your shadow would start directly below you while under the streetlamp but then as you walk away you will see it get longer and longer until finally, if you walked toward a wall you would see that your shadow is the same height as you and beside you on the wall with the street lamp far away but to your side instead of overhead.