I purchased on eBay an Olympus Zuiko Auto-S 50mm F1.8 lens (the lens is marked "made in Japan"), Serial No. 5870379. Although used, the lens appears to be in near-mint condition.
I also purchased an adapter to fit this lens onto a new Panasonic DMC GF1 micro 4/3 camera body. I take pictures through a research microscope, through a telescope, and just for fun. In the first 2 of these cases, focus is critical. One of the main reasons for selecting this camera is the live on-screen enlargement capability (which is super) as a focusing aid. The adapter works ok as far as coupling the lens to the camera. There is, of course, neither "auto" nor electrical connection.
Here's the problem, with the OM lens mounted on the adapter, the iris opens and closes smoothly, but only when holding the rectangular button on the side of the lens. Inside the lens are 2 spring-loaded articulators that are clearly designed for automatic control of the iris. If I hold one of these at its limit, it has the same effect as holding the rectangular side button, i.e. the iris opens and closes smoothly as the f-stop is changed. Left to its own devices, the lens stays wide open.
Bottom line: I don't know if I have a lens that isn't working the way it should or if there's some function of the lens that I just don't know about or if I have an adapter that doesn't do what it should.
It is clear that lots of folks use adapters to connect any number of lenses (including the Olympus OM Series) to any number of cameras. I have fair experience with Pentax & Vivitar lenses, with adapters to paste them onto bayonet or screw mount cameras, and with adapters to paste cameras to telescopes and to microscopes, however...
I have a problem here and I'm hoping someone can make some helpful suggestions. If my problem points to the adapter, perhaps you could suggest a brand that you know works with OM Series lenses.
Thanks in advance for your help,