Disclaimer: this is not a "which is the best camera" thread. I have both hands-on experience with and time spent researching each of these, and I can say unequivocally that there is not clear ranking. Each has advantages over the other two and several categories (e.g., ergonomics) are purely subjective. This is in "Other Systems" for a reason and the only reason that the E-M5 is in the discussion is that I own it and I can't afford two cameras/systems. I'm simply looking for a little input from posters who own or have owned these cameras, as to how the two FF models compare with each other and, to a lesser extent, to the E-M5. I don't know if I could/would actually make a change, so this is mostly hypothetical for the moment. ------------------------------------------------------------------------ I mentioned in another thread that there is a set of conditions that I shoot in that make the E-M5 just short of everything that I need. It's truly an amazing camera and I will likely stick with it, but these conditions keep me thinking. What are they? I shoot people (candids) in generally poor light under conditions where a flash (or often even a focus assist lamp) would not be appreciated. Add to that my preference for using zooms, since I can't always "zoom with my feet," and I find myself trying to shoot a moving target at f/2.8 and ISO3200 with shutter speeds slower than 1/30 of a second. I try to time my shots with those little pauses in the action, but I've lost a lot of shots to the presence of just a little motion blur (look OK on rear LCD, but zoom in just a little and the details go fuzzy) or not being able to focus track well. Oh, and also I do like shallow DOF in many (not all) cases. If I stay with my E-M5, my preferred kit would be (well, today ... it keeps changing) P12-35, PL25/1.4, P35-100 and O75-300. Basically, the classic 20-70, fast 50, 70-200 set, plus a long tele for fun. Adding that to the E-M5 w/ HLD-6, even without the 75-300, that's over $3500. I don't consider APS-C's to be enough of an advantage to justify the disadvantages, so that led me to ponder a 6D or D600. I spent some time handling them (the guy at my local camera store directed me to a small dark room with the two and left me to play with them.) Between that, watching reviews with actual comparison tests and looking at DPReview's RAW comparison tool, here are my findings: Canon 6D (+) Best high ISO performance (two stops over E-M5: 12,800 looks like 3,200; a third or more of a stop over D600 and higher native range) (+) Best grip of the three (subjective) (+) Easiest menus/controls of the three (+) Center focusing point in low light (-3 EV rated) (+) Largest selection of top glass (new and used) (+) While I don't care much, GPS and Wifi are built-in for free (-) Rest of focus system is limited in # points and coverage (-) Biggest body (though D600 is thicker) Nikon D600 (+) Better high ISO than E-M5 (more than a stop; probably 1-2/3) (+) Dual card slots (+) Built-in flash (not a big deal, but the other two don't have it) (+) Grip is better than E-M5/HLD-6, mostly due to being taller (+) Best tracking focus of the three, but .. (-) Limited coverage of focus system (it basically has a D7000 focus system) (-) Limited native high ISO (wish it went to 12,800 without going into extended range) Olympus E-M5 w/ HLD-6 (+) Size! Size! Size! Size! Size! (+) Ability to go very small w/o grip and with 14/17/20 (+) Cost (body and "comparable" 2.8 zooms) (+) Other than the slight lag, I like using an EVF (+) Full coverage focusing system (+) Full magnesium body (vs magnesium/poly mix) (-) Noise control is very good for the sensor size... but still well behind the other two (-) Tracking is poor (-) Hanging pinky grip (I have long fingers) (-) Significantly wider depth of field (f/2.8 is still a stop deeper than FF f/4 zooms) On paper, I preferred the D600, but when factoring actual use, my preference was slightly toward the 6D for its low-light performance, ergonomics and "kit lens" (24-105/4L IS). For that same $3500, I could get (close to) a 6D w/ 24-105/4L IS (or 24-70/4 IS kit from Canada for $400 more), 50,1.8 and 70-200/4L IS (or replace the f/4's with older f/2.8 non-IS zooms; maybe even a "magic drainpipe"), which would give me roughly a stop faster shutter speed (for ISO's with the same acceptable noise level) and a stop shallower DOF versus the E-M5 (two if I go with the f/2.8's, but I'd lose IS for those other times when I'm not shooting moving subjects.) I'm still relatively young, so my back is strong, but I do realize how much bigger that system is. I'm trying to figure if there are enough times that I bring my E-M5 kit, but wouldn't bring the 6D. A few, but mostly if I would go with the E-M5/20 combo, which is still only jacket-pocketable. The 20mm is about halfway to a 1"-sensor compact, which is truly pocketable. Again, these points are all specific to my uses. I love :43: and the E-M5; they have given me many great shots. I'm just trying to decide if it's right for me at this time. Any thoughts?