Which of the following constitutes an eyewitness claim?
(1) "I saw it happen."
(2) "Bill saw it happen."
(3) "Bill says he saw it happen."
Only the first is an eyewitness claim. The second is a claim that someone else was an eyewitness. The third is a claim that someone else claims to be an eyewitness. Only the first is a claim by someone that he himself saw something. In a court of law, only the first would be admissible to prove that "it" happened.
So how many eyewitness accounts of Jesus' resurrection does the New Testament contain?
I count one.
That's it. In 1 Corinthians 15:8, Paul says that "he appeared to me." Other than that, not a single New Testament author writes that he personally encountered Jesus after he rose from the dead. The gospels are all written in the third person. None of those authors put themselves in a position to see the events they describe.
What brought this reflection to mind was the following statement, which I ran across on an evangelical Christian's blog: "on one occasion alone over 500 claimed to have seen him." In fact, we have no account of these claims. In fact, we have Paul's claim that 500 people saw him. That is a very different thing. It is one claim rather than 500.