I have a question about deferred shading.

If I understood it correct, I am just pushing my geometry though a shader stage so that I have the position normal and color information about the frontmost pixel.

This way I only have to lit pixel that are acutally visible to the camera right?

Now my university tells me that I have a complexity of #objects * #lightsources without deferred shading and with deferred shading I would have a complexity of #objects + #lightsources.

This make absolutely no sense to me.

Let's say I have a scene with 1000 cubes, but the camera only sees one cube. With deferred shading I only calculate the lighting for one cube right? (and only the pixel that are actually visible)