That's certainly the problem with a slide bar. I prefer medium format stereo, but my primary stereo camera is still the Stereo Realist (35mm). It's just easier to carry around, can handle a moving object without any problems, and it's more discrete from those times where you're not supposed to be taking pictures (not that *I* would do that of course, I'm just sayin'...). For architectural stuff I do prefer medium format transparencies, but the mounts are kind of expensive (for me anyway) so I try to keep to the more serious stuff to keep the cost down.
- Randy