Why would I try taking pictures of the moon? Pretty sure none of my lenses zoom far enough. Also, that means going outside in the cold. Good luck holding a tripod, the dog, and your camera. Just to find out you can't zoom in far enough.
There's no point in using my 28mm Canon FD lens.
Actually, it's almost as sharp. Still not any point, the Panasonic has auto focus, that doesn't always work. The focus ring on the Panasonic is smoother, if you need to use it.
Panasonic 25mmVivitar 28mm
Look at the remote, click the image and view the original size, then zoom in. The text is more readable on the Panasonic.
If all you care about the phone, then either lens is good enough. The top of the phone might be slightly sharper on the Panasonic. Either good enough for eBay. If you like getting scammed by buyers.
Panasonic 25mm @ f6.3
You can read the text on the 3DS games.
Panasonic 25mm @ f1.7
It's got bokeh too. Think I only paid $150 or so for the lens, can't be beat if you want auto focus. The manual focus lenses probably won't be as sharp, even stepping down.
To be fair, the Canon FD lens was cheaper most likely, but the adapter makes the total investment more then the Panasonic, the adapter was $150.
What's the point in my $150 adapter? You aren't saving money buying it. You'd be better off selling your Canon FD lenses, if you have a bunch, then buying the Panasonic or some other lens. The manual focus made for micro 4/3 lenses, are probably just as good as Canon FD lenses.
If you have no Canon FD lenses, then don't bother paying a bunch of money for an adapter, and then more for lenses.
7artisans makes some cheap manual focus lenses.
Also, if you have the original E-M10, the adapter may suck on it. You'll have to fiddle with it, to figure out what setting is wrong. I can use the screen to focus on the E-M10 Mark II, and the pictures are much sharper then the original E-M10. Not touch to focus, just a magnify view, and using the focus ring, but I don't have to look through the viewfinder for good results.