Since no one else has answered, I will provide my opinion. Let me mention that I have not seen a total eclipse since 1991, so I do not remember the diamond ring affect explicitly, and my notes do not mention it.
I think the diamond ring can only be seen with the naked eye. It consists of the inner corona on one side of the moon and the last bit of photosphere on the opposite side of the moon. I believe that the inner corona is not visible in any type of filter. That is why I am speculating that the diamond ring is a naked eye phenomena only.
WARNING The diamond ring occurs as the partial phase ends and totality begins, and then when totality ends and the partial phase begins. Of course you need to be extremely careful when looking at the partial eclipse with the naked eye. Essentially, you cannot look! It would be better to use a hand held filter to block the photosphere while looking at the corona without the filter.