Reddit reviews Neewer Plastic body (metal bayonet) AF focus Lens Mount Adapter for 4/3 four thirds lens to micro 4/3 Olympus Pen and Panasonic Lumix cameras, fits Olympus PEN E-P1 P2 P3 P5 E-PL1 PL1s PL2 PL3 PL5 PL6 Panasonic Lumix G1 G2 G10 G3 G5 G6 GF1 GF2 GF3 GF5 GF6

> I'm going with the 28mm F/2.8 over the 50mm F/1.4 because I'm assuming it will be able to create a better depth of field...

• if you mean "deeper depth of field" - you're right. The shorter lens will have a wider field of regard and a deeper depth of field.
  
  >...for some reason [the Olympus 25mm 1.8] doesn't seem to work with the Olympus Evolt E620, which is what he has. If you know off the top of your head, is there an adaptor that might let it work?
  
  Your dad has a classic 4/3 mount camera and your G6 has a micro 4/3 mount. If you want to share lenses, you can buy an adapter for your camera and use all of his lenses. I use a [$99.95 Panasonic DMW-MA1 adapter] (http://www.amazon.com/gp/product/B001ISKNKK/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B001ISKNKK&linkCode=as2&tag=battleforthew-20), but you can get [third party adapters for about 50% less] (http://www.amazon.com/gp/product/B00CHZ44SA/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B00CHZ44SA&linkCode=as2&tag=battleforthew-20).
  
  Unlike old Minolta or Canon lenses, 4/3 lenses will give you electronic control of autofocus and automatic exposure - but their autofocus and autoiris motors are slower and noisier than native micro 4/3 lenses.
  
  With an adapter on your G6, you and your dad could share something like this [$189 brand new Olympus 35mm f3.5 lens for classic 4/3] (http://www.amazon.com/gp/product/B000BTFZZA/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B000BTFZZA&linkCode=as2&tag=battleforthew-20) or this [$276 used Sigma 30mm f/1.4] (http://www.amazon.com/Sigma-Olympus-Panasonic-Digital-Cameras/dp/B000FBFXY2/ref=sr_1_1?m=A2L77EE7U53NWQ&ie=UTF8&qid=1420470547?tag=battleforthew-20).
  
  I shoot with classic Olympus and Sigma 4/3 lenses and love them.
  
  Again, hope this is helpful!
  

As far as I know Rokinon does not make any cine lenses compatible with micro 4/3. What you have is probably a standard 4/3 mount, which is different than micro 4/3.

I use the exact same lens a lot, but the Canon mount version. If you get this 4/3 to micro 4/3 adapter it will work on your GH4 just fine:

http://www.amazon.com/Neewer%C2%AE-Plastic-bayonet-Adapter-Panasonic/dp/B00CHZ44SA/ref=sr_1_1?s=electronics&ie=UTF8&qid=1417759880&sr=1-1&keywords=4+3+to+micro+4+3+adapter

Sadly, no. An f/4 lens is too slow for indoor use.

And using a non-system lens will force you to focus and set aperture manually.

You might want to consider a used Sigma 70-20mm f2.8 for Olympus 4/3 mount with a [$52 third party 4/3 to micro 4/3 adapter] (http://www.amazon.com/gp/product/B00CHZ44SA/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B00CHZ44SA&linkCode=as2&tag=battleforthew-20) instead. This lens will be fast enough to work indoors - and your autofocus and automatic aperture control will work.

You can [get one via eBay for $460] (http://rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&pub=5575034783&toolid=10001&campid=5337235943&customid=&icep_item=221601305940&ipn=psmain&icep_vectorid=229466&kwid=902099&mtid=824&kw=lg) or [from Amazon for $679] (http://www.amazon.com/gp/offer-listing/B0014RBYTE/?ie=UTF8&camp=1789&condition=used&creative=390957&linkCode=ur2&tag=battleforthew-20).

Again - hope this helps!

HCR