Nether fog not allowing further view on higher render distances

Putting the render distance above 16 chunks would render more chunks, but you can't see any further than your render distance being on 16.

Putting render distance above 16 should allow players to see further, by increasing the fog distance.

But I just got worse performance and couldn't see any further.

I have some screen shots of 16 chunks vs 32 chunks but there's no difference between them.

Optifine made no difference since I checked both vanilla and OF.

1. Put render distance above 16