85 1.8 vs 70-200f4 outside portraits
Both are excellent lenses. Under certain conditions one might be better than the other and vice versa. For example, if you want to compare at the 85mm focal length the prime is 2+ stops faster for narrower DOF. However, comparing photos taken from the same camera to subject distance the longer reach of the zoom is capable of more compression between the subject and the background. In the end, its the intended result that matters.
|AT-6 Harvard by jarud|
from Trainer aircraft
|Monarch butterflies winter roost at Pismo Beach by cjf2|
from Safety in Numbers (Nature)