Yes—50mm and 85mm are both useful for portraits, but they do different jobs.

An 85mm is a classic choice for tighter portraits like head-and-shoulders. It gives more background isolation and a more compressed, flattering perspective, but it also requires more working distance, which can be limiting indoors or in tight spaces.

A 50mm is more flexible when you can’t back up. It’s often better for upper-body portraits or more environmental portraits, where you want to include more of the scene.

As for f/1.8 vs f/1.4: the main benefits of f/1.4 are a little more low-light ability and slightly shallower depth of field. But that extra shallow depth of field can make focusing harder, and many fast lenses are softer wide open anyway. If you won’t often shoot at f/1.4, the advantage is smaller.

Based on the answers, the 50mm f/1.8 can be a perfectly reasonable, sharp budget option, though its build quality is often considered poor. The 50mm f/1.4 has some benefits, but whether it’s worth waiting for depends on how much you need the extra speed and whether build/handling matters to you.

So: don’t think of 50mm as replacing 85mm. Think of it as adding a different portrait look and a more practical option for tighter spaces.