Yes, NOKIAMA I second that on the Metabones adapters. I have the Metabones Nikon F to m43 and also the Metabones contax G lens to m43, they are very well made and precise, very good machining and finishing and solid, once again you usually get what you pay for.If you are going to actually use the adapter over a long period of time then get the best you can afford.This is a good thread.
I bought myself a Nikon to m4/3 mount from eBay. It's a Japanese brand called Metabones. The store owner is also a forummer here by the name Lasjas. My review on this adapter is simply outstanding. The built quality is top notch. I really have no complaints actually. I really recommend Metabones. Contact Lasjas and he'll give fellow forummer a generous discount.
I've spent from $180 on the premium adapters to $25-ish on the economical Fotodiox (made in China, but available immediately from the USA-based Fotodiox).
In my experience, while the $180 adapters are very nicely built and the $90 adapters are nice as well, unless you don't mind spending the big bucks, I'd recommend the $25-ish Fotodiox adapters as perfectly serviceable and readily available in the USA. They're less expensive when purchased through Amazon than directly from Fotodiox's website. They work just fine for me.
Pentax K/PK to m43
From R-aerphoto (c.kee) on eBay
Pro: Very nicely made, beautiful fit lens-to-adapter, nearly as good a fit adapter-to-camera as a native lens, very inexpensive, came with an endcap, very quick service HK -> UK (6 working days)
Con: Can't see any at present
Both adapter box and adapter itself are branded "Pixco"
Novoflex or Rayqual both make adapters with precise flange distance and properly fit bayonet mounts at both ends. They cost a lot more than the cheap sloppy ones. I use both Rainbow Imaging and Fotodiox adapters and live with the focus past infinity and somewhat loose feel. $20 vs. $150 and up.I'm a OMD5 user and looking for a good quality OM to M43 adaptor.
Having read the thread, it seems to be a minefield when it comes to choosing a suitable adaptor.
Being an engineer I hate it if things are not right, and having read about Fotodiox there seems to be too many instances of 'slop' on the lens to mount interface.
Any recommendations for a good quality adaptor that's not going to damage the camera and not going to rattle or feel loose?