According to the Panasonic lens chart for the 14-45 lens, the minimum focus distance is 1 foot or 12 inches. I haven't tested the G1 in the more traditional macro/close-up type approach. I didn't get the impression that the camera likes getting closer than 12".
From @2-3', I was able to engage the Extended Zoom (2x) + 4x digital + a Tcon 1.7 teleconverter (1200mm) and got surprisingly good results. I'm not suggesting you do it, but it worked.
So this is a major concession in comparison with much less expensive cameras' focusing distances of one to two inches. Anyone with ideas as to why this is so. I used a Nikkormat with a Nikon macro lens for many years and have considered a Nikon digital body to allow continued use of the lens. Anyone with any thoughts on marrying such different technologies?
I'm not sure which direction you're coming from here.
Are you comparing an old film 35mm slr with a macro lense to the G1 with the 14-45 telephoto "kit" lens? If you were led to the micro 4/3 because of it's ability to adapt to slr film lenses, while that is very popular and works well, it does require considerable knowledge of both the manual film lenses and the digital body used. If I wanted a "macro" lens, I'd just get one for the camera.
The more conventional P&S cameras can focus easily at 1/2" in macro/close-up mode.
I don't concern myself with dslrs, but your Nikon lens may well adapt to the Nikon body, but a user would have to provide the feasability and potential results. I know that it's done, it's just not my interest. If that's what you're after, you might try posting on the Nikon or DSLR forums.
Off the record: "I" was able to focus anywhere from 28mm to 720mm w/14-45 lens from 6". Panasonic says 12".
I have the kit 14-45 lens and have had good results with a Tiffen closeup filter (a +10) - it wasn't cheap, but it does allow the camera to focus down to about six inches and the image quality is quite good.