What the Noblex does is allow you to make multi-exposures as many as you want. I have a 135U and it has down to a 1 sec. exp time. I then can set it to multi and take as many 1 sec exposures as I want or until the batteries die..
So you can take long exp. not as easy as having a bulb setting but it does work.

And yes the lens is just as good on the 135 cameras also..