It would seem that we all have very different opinions on brightness. I suspect that the cause is our differing ground glasses, rather than our eyes being that different. I have only used my 90f8 on my Ebony, which has a bright GG. I can imagine that using it on the coarse and dingy GGs on some cameras might be a very different experience. I certainly had not trouble focussing at all. It was very obvious when focus was attained.