Diffraction and gravitational lensing

[Dylanden]

Hello.

And i have a dumb question about light.
When the diffraction is studied, we look at where the light is coming. But not where the light comes from.
When the gravitational deviation is studied, we look at where the light comes from, but not where the light comes.

What do you think?

thank you very much

Dylan

 

[Nugatory]

When we're studying diffraction, we know where the light source is because we put it there when we set up the experiment. So we're trying to see how diffraction affects the path of the light.

When we're studying gravitational lensing we know how the light is affected by gravity and we're trying to figure out where it came from.

 

[Dylanden]

Hello

Thank you for your answer.
But i have made a little expermentation. In a old raiway tunnel.
Just use ma camera and a small light
And at half distance, slowly hide, obscure the light by the side with an opaque screen. It seems to me that the light does not always come from the same direction on the video.
But i am not sure

Dylan

 

[Dylanden]

Hello

And you can have a look in the Feynman books, there is light that come in the geometric shadow.
I think.

Dylan