Hello, I have to wear my glasses to focus so I bought a Hoodman hood for Nikon square eyepeice.I'm having problems installing the hoodeye. The directions say to remove original eyepiece by squeezing both sides of the rubber eyepiece together and lift off. There is no rubber eye piece. I bought the camera used and maybe I overlooked it. Am i right in thinking that the rubber eyepeice is missing? If not, is there anyone familiar with the eyepeice and installing the hoodeye? Thanks!