I changed my parting, but my hair volume looks different—it's just an optical illusion, right?

Lately, I've tried parting my hair in the opposite direction to usual.
It felt like the top of my head looked much thinner than I expected.

It looks okay when viewed from the direction I usually ride.
I'm not sure if it looks that way because of the parting direction or if there is actually a difference in hair density.

I'm wondering if changing the direction of my parting is meaningful when checking for hair loss.