Not much. My field of vision is limited, especially with the large “nose” on the stormtrooper helmet.
That’s why stormtroopers are always looking like they are scanning the room from side to side, seemingly never meeting your eyes… Here’s the secret: We have to turn our head and look out of the corner of our eye to see what’s in front of us!
The Boba helmet is a bit better. I can see things right in front of me. I do have blind spots in this helmet as well, but not nearly as large as on the stormtrooper helmet.