Thanks!
Thanks, guys!
It's something that I've always wondered about, especially in those rare cases where I want to convert from, let's say, an ISO 80 film to an ISO 100 film.
My Zeiss lens will actually stop in-between the clicks, and it will hold still enough for me to shoot without worry about it slipping. However, there's not very much space in-between the clicks. But at least I now know that the 1/3rd stops exist in the space between the clicks. At first, the idea of doing it seemed a little unconventional. But I will definitely give it a try, especially since my light meter evaluates light down to the 1/10th of a stop.
And yeah, it looks like I'll have no luck with the in-between shutter speeds. As long as the aperture will let me use the 1/3rd stops, I won't even need to worry about flexibility with the shutter speeds.