Whilst I love my Olympus OMD EM5, I have become a little dissatisfied by the noise level and DOF control. I really enjoy using MF lenses and find my Voightlander 25mm f 0.95 is almost permantly attached to my camera but mostly I stop it down to around f1.4 as it is really soft wider than this. I'm considering selling a couple of lenses I rarely use and dipping my toe into Sony Full Frame territory but could probably only afford an A7 (first version). I would probably pair it with a Voightlander 40mm f1.4 or similar and think I'd be happy just using this combo for several months and just pull out the Olympus if I feel like shooting some other focal length.
I'd like to ask any forum members that have experience of the two systems if they have been happy with or regretted similar changes and why? I'm primarily an enthusiast and used to take lots of travel shots from around the world but since I have had kids I mostly take photos of my family now. Whilst the Olympus does a wonderful job for this, I can't help but be critical of my own shots and would really love to explore the additional creative freedom that FF would offer.
I use both M4/3 (Panasonic GX7) and Sony A7 and A7s.
I find that I am happy to use the A7 at ISO 12800 as maximum with auto ISO, the GX7 I don't like going over ISO 3200 though I have auto ISO set to 6400 now out of necessity.
I am spoiled though with the A7s and that is my low light and video camera of choice.
In good light the A7 is the best though all three have their strengths and weaknesses.
I also use a mix of lenses with the A7s/A7 including some native (if you DO get an A7, save for the Sony Zeiss 55 1.8).....but a lot of Canon EF lenses.
There are adapters now that allow the Canon lenses to be used on BOTH M4/3 and E mount so I can use one lot of lenses with double duty (was triple duty before I sold my Canon 7D).
Generally, I much prefer the A7/A7s and the GX7 is more a secondary system now for me but since getting the kipon EF to M4/3 AF adapter I have had some fun with the GX7 again.
The GX7 has EV -4 AF unlike the A7 but while it has that low light focus, it is not a camera I want to USE in low light.
The A7 only auto focuses to EV 0 but that is still quite low light and lower you can always use manual focus.