Hi
I was thinking to go for a second hand E-PM1... few questions if someone wants to answer.
1. Would it fit to a jacket pocket?
It depends on the jacket pocket. Pens with the smaller lenses fit ok in most jacket pockets.
2. Can I used normal flashes with it? IT looks like it has a hot shoe
Yes, you can use either flashes that support the Olympus protocol or generic flashes where you have to do more work to get the shot properly illuminated. When it was sold new, it came with a clip-on flash that could be used to control remote flashes. If you are using a generic flash, note that page 60 of the fine manual says that you should use a flash that puts no more than 24v through the hot-shoe (some of the flashes designed in the 1970's could send hundreds of volts through the hot-shoe, and fry modern cameras).
3. How much money would you think it would be a good deal only for a body?
Well given Olympus is currently selling the E-PM2 with 2 lenses for $399 (note this is a US only sale, and the promotion is ending at the end of February), I wouldn't pay too much. KEH.com is selling one for $126. And Olympus USA is selling reconditioned E-PM1's for $138.
4. Is iso 800 good enough?
It depends on how picky you are. I tended to go up to ISO 1600 on my E-P2 which came out 1-2 years earlier, and has an earlier generation of the 12MP sensor used in the E-PM1. But at 1600, I do have to do some noise suppression in post processing.
5. Can I use adapted lenses?
Sure, but IMHO, unless you get an electronic viewfinder or something like a clearviewer, it is hard to manually focus lenses when you are using the back lcd.
6. Is there any very compact zoom lens that would fit together at my pocket?
The Olympus 14-42mm II-R lens that was the kit lens for the E-PM1 folds down to about 1/2 size when you put it in your pocket is probably your best best for a zoom lens. It isn't a bad lens. Like most of the zoom lenses until you get to the $800 lenses, it is f/5.6 on the long end, which means if you are shooting indoors without a flash, you will need to push up the ISO somewhat. It has an equivalent focal range of 28-84mm.
Note, Olympus no longer offers lens hoods with the lenses, and you can pick up JJC knock-offs of the lens hood for a few dollars on ebay. The one I got can be mounted backwards to save space.
There is a new 14-42mm EZ lens that was just announced that is even smaller. I don't know if it is shipping yet. I think the price was $350 or so.
I just picked up the Stylus1 and it would fit the bill (though at $700 it isn't cheap). It can do the equivalent focal range of 28-300mm with a f/2.8 lens. It is slightly thicker than just the Pen bodies by themselves, but much thinner when you consider the lenses on the Pens. There are several discussions about the Stylus1 in the Olympus compact camera sub-forum. Here is one of the posts, where I compare the E-PM2 and the Stylus1 (be sure to read the whole thread):
http://www.dpreview.com/forums/post/53175972
If you want to go cheaper, with more zoom, and thinner, consider the SH-50. It has less bells and whistles than the Stylus1, but if you need zoom and are shooting in good light, you might want to consider it. There is a frequent poster in the Olympus compact camera forum (Henry Falknet) that can promote the camera. For me, one of the sellers for the Stylus1 is having the viewfinder for shooting in bright sun.
