What is this effect?

Is this effect something that attaches on the front of the camera or is this something down in post production? It is not just a transparent matte beacuse the edges actually show the image... Really want to figure out how this is done. Any help would be awesome!

Thanks!

It is called lens flare. I can happen organically in the camera lens if the light hits the glass at the wrong angle. This is why we put a Matte Box around camera lenses, to avoid lens flares. But you can also add it in as a post-production special effect. There are lots of plugins on the market that do this.