I waited about 2 months to write this review to give me real experience with the Oly EM-5 MK II. I have been a die hard Canon person. Last summer at 62 I hiked all over Glacier Intern'l Park with a 70D, 100-400L, 10=22 EFS, & 18-200 EFS. I did have the good sense to leave the 70-200 f2.8L home, but the weight of what I did bring was a killer. So before my 2 weeks in England and France this month, I decided to go Olympus "light". One of the reasons I had not done so before was that as a macro and video fan, I really valued the fully articulating LCD and no mirrorless except Samsung had this, until the EM5 – so I took the leap.
A month before I left for London, Monet's Garden, and a 6 garden tour of southern England, I purchased the camera, 14-150mm ED, 12-40 ED 2.8 pro, 40-150 2.8 ED pro, the 1.4 teleconverter, and the 60mm ED 2.8 Macro. The 40-150 heaviest of the lenses, but is 1/3 the weight of either the 70-200 or 100-400 Canon. I'm convinced the optics of the pro-line of lenses is as good as Canon. The 14-150mm is slower and not quite as good – but man-o-man, a great walk around lens with great results. All this stuff plus the little flash fits nicely into a daypack no problem and without strain (smallish Lowepro CompuDay pack).
Having read on line that the menu system is complex, I read the entire manual prior to opening the box and then spent a month messing and testing. Note that IMHO the menu system is NOT complicated, it's just that there are so many options and features that it takes a while to understand and use what is available. I've not used all the modes, filters, etc. Much to learn. But getting the most useful settings and using the Myset features is not hard. After a bit of messing around you'll easily get the logic of the menu system and become very facile at making changes in the field and on the fly. Tip: have the manual in pdf format in a reader on your smartphone for reference till you're comfy with it).
Image quality is excellent – comparable to my Canon 70D. There may be a noise price that you pay starting at about ISO >1600 compared with full frame systems, but my impression is that it's not much more than with my 70D. However, at Trooping the Colours in London, it was gray skies and using ISO 1000+ and the f4-5.6 14-150 (not the pro) and I got great shots of the Royal family even with pretty extreme crops and a bit of LR adjustments my shots of the Royal Family are winners. I am thoroughly happy with my selection of this camera and don't anticipating much use of my Canon system (tho I can't quite bring myself to sell it, yet).
Some "minor" issues and findings: trying to hit the OK button by touch often resulted in hitting the 4-way arrow pad which changes the focus center – finally getting the hang of that. In general, it takes time to get used to hitting the right buttons by feel without looking. Also, the default set up has the exposure bias adjusted with the front wheel. I found that it got turned sometimes when putting the camera in the bag and such and then the exposure bias was set inadvertently. You can change that set up, but I found that I like it the way it is and I just learned to check that routinely - if bias is set, it's displayed clearly in the viewfinder and LCD. Battery life, as noted in other reviews, isn't great. I have 4 batteries and if shooting all day long, will use 2, occasionally a 3rd if a particularly intense day of shooting. I have the battery grip which I'm not 100% sold on. I like the small form factor and weight of the camera without the grip (I have fairly large hands but still love the size and ergonomics of the camera without the grip - but the grip is growing on me), and the grip does give you all day battery life AND I really like the 2 extra customizable function buttons which is perhaps the best feature (for me) of the grip.
Finally, one word about the pro line of lenses: Besides great optics, they give you an additional function button AND a focus ring that has 2 slide positions – slide it back for manual focus regardless of what the camera is set to. In using the lenses for the first time, I inadvertently slid the ring back and not knowing about this feature thought the lens was defective – none of the autofocus modes could be used. I actually got an RMA from the retailer to return it, but then contacted Olympus and they responded promptly letting me know about the feature. Felt pretty stupid, and I cancelled the RMA and It has become my favorite feature of the these lenses. By the way, the only lens I wasn't thrilled with was the 9-18 f4-5.6 zoom. Didn’t think it was as sharp as it should be. I returned it and will wait for the "pro" wide zoom to be available.
I did consider the Sony Full Frame mirrorless system when deciding on this purchase. In short the reasons for going with the EM-5 II was, form function and weight, OLY 5-axis stabilization (which works great –including video) – the newer Sony's have this, but many of the better lenses have OSS adding weight and cost. As for the the lenses. check out the equivalent lenses in the Sony line up. Either you won't find them or they'll be quite a bit heavier, larger, and slower – they have no zooms currently at f2.8. Finally, at the time of my purchase, the Sony's did not have the fully articulating LCD - which if you do macro and video work is a must in my mind. But, if you need the reduced noise at very high iso that the full frame sensor might give you, take a good look at the Sony line up.
I highly recommend this system for enthusiasts who want to lighten the load and are willing to put up with a bit more noise at high ISOs. It's an incredible camera with a huge scope of special functions I haven't gotten to yet.