The ET-67 is the lens hood for the 100/2.8 while the ET-67B is the lens hood for the 60/2.8. I just traded my 100/2.8 for a 60/2.8 and as he was not interested in any lens hood I thought I'd try it on the 60/2.8. To my surprise, there is no vignetting even at 2.8, even though the ET-67 is quite a bit longer than the ET-67B. Thus I'm going to keep it.
The only drawback is that as the ET-67 is longer than the 60/2.8, it is impossible to reverse mount the lens hood on the lens so I'll have to carry it separately. As I am a bit of a lens hood nut, I don't mind this.
Just thought I'd share this piece of info with you.
