Sorry if this has been asked. I'm new to the M43 system. Planning to buy the E-M5 with kit lens (12-50mm) as my first M43 camera. The shop here will give me a free MMF-3 adapter. I found a used 4/3 lens on sale in one shop here for $100... OLYMPUS ZUIKO DIGITAL ED 40-150mm F4.0-5.6 My question is if this lens will focus automatically on the E-M5? Or do I need to focus manually? If this lens focus automatically, how's the speed? I hope AF speed is tolerable. Also, what can you say about this lens. Is it a good buy for $100? Or should I buy other lens? (NOTE: The 20mm f1.7 lens is on my To-Buy list. I just want to buy a cheap usable 4/3 lens so that i can use the free MMF-3 adapter.) Thank you in advance for your reply.