I'm looking for something from the obscure department.
I want a zoom around 35-100mm that maintains focus (or close to) over that range and is light weight.
After that, everything else is pretty flexible - manual focus, poor quality optics, etc are all OK.
You may be wondering why. 
I'm into astrophotography and need to align my mount to the celestial pole. We don't have a nice bright Polaris in the southern hemisphere and the closest stars we have are barely visible in a dark sky. There's no hope in town. So I use the camera. That works well with the 85mm lens once I'm close, but it takes a while to star hop to the region at that focal length.
Most reasonable manual focus zooms from the film days are parfocal but tend to be quite heavy. Auto-focus lenses don't need to be parfocal so if they are, it's coincidence more than design. The only way to find out is to try them. So far, the humble 18-55mm non-is kit lens with a 2x converter is my best option.
As I said, image quality doesn't matter much. As this is the only use I have for this lens, cheap would be good.
Maybe something from the film EOS cameras that I can pick up for a few $.
Any options would be appreciated.
Steve.
