What are the usual expected circumstances to accepting eye witness accounts in a court of law?

Yes. And then the witness gets cross examined. And then the jury (or judge) evaluates the accuracy of the eyewitness’s description.

Long before there were surveillance cameras and cellphone videotapes, there were eyewitnesses. A recording is infinitely more accurate than the human memory.

Eyewitness accounts are famously unreliable.

Since the eyewitness is under oath, it must be assumed that they are telling the truth.

As @SecondHandStoke said eye witness accounts are notoriously unreliable. Still in liu of any other evidence they are considered. The judge or jury evaluates and assigns weight to that testimony. It can be deemed accurate or thrown away entirely. Obviously supporting evidence would help in that determination.

@kritiper I’d guess that eyewitnesses generally do give truthful statements, but it’s truth as they recall and interpret it. Memory is fleeting, and it’s heavily influenced by emotions, biases, and other subjective factors.

@Love_my_doggie True. But we’re talking about circumstances in a court of law, where civil life is different than normal goings-on out here in the wild lands. For example, in a court of law you are innocent until proven guilty whereas outside of the court (the wild lands) you are guilty until proven innocent. Or so it seems to me…
The court cannot assume that the witness is lying, otherwise the court system would be a mockery. Memory may be fleeting but one must tell the truth, the whole truth, and nothing but the truth, to the best of their ability to do so. Then the jury considers the consequences, and accuracy of that so-called “truth.” It ain;‘t perfect, but neither are the participants.