I’m afraid I’m going to belabor a point that I've been exploring as I contemplate the choice between a GX7 and the Olympus E-M1, but I will, i.e., as to the so-called (in DSLR lingo) "AF-on" or back-button focusing. As I read he knowledgeable responses from folks in the Olympus forum section of M43, it appears that AF-on focusing, functionally similar to that found in all of the advanced Nikon DSLRs, can be set up on the E-M1 with a bit a bit of somewhat complex maneuvering through the E-M1 menus. AF-on focusing as I have and do experience it in my Nikons makes it possible, given the appropriate menu settings, to 1) press either a dedicated AF-on button (in the Nikons and, by the way, in the Panasonic GX1 where that function can be assigned to the AEL/AEF button at the middle of the upper back of the body just below the top deck), lock focus and let that button go--for still subjects--or continue to hold down the button for subjects that are likely to move (commonly called AF-s and AF-c, or, sometimes, S-AF and C-AF, respectively in the autofocus world), and 2) squeeze the shutter release button (no half-press required) to execute the photograph. The primary issue for me with the GX7 is what I read in the GX7 user's manual on page 48, to wit: “…Fixing the Focus and the Exposure (AF/AE Lock) Applicable modes: This is useful when you want to take a picture of a subject outside the AF area or the contrast is too strong and you cannot achieve appropriate exposure. 1 Align the screen with the subject. 2 Press and hold [AF/AE LOCK] to fix the focus or exposure. • If you release [AF/AE LOCK], AF/AE Lock is canceled. • Only the exposure is locked in the default setting. 3 While pressing [AF/AE LOCK], move the camera as you compose the picture and then press shutter button fully. A AE Lock indication • When [AE LOCK] is set, after pressing the shutter button halfway to focus, press the shutter button fully…” This appears to indicate that the button must be held down to keep focus locked, unlike the provisions in the other camera bodies that will permit releasing the button once focus is achieved (for still subjects) allowing a bit of leisure for the photographer to perfect the final framing and thoughtfully press the shutter release in one smooth motion. Am I mis-reading he GX7 manual on this score? And on a much more minor point (I hope) re the AEF/AFL button, does anyone think that that button protrudes just a litttle too little from the focus selector lever surrounding it. It seems to me from jut a few too few moments of handling that it might be difficult in some circumstances to get a good, solid push on the button, unlike most such buttons on a few other camera bodies where those buttons are not surrounded by another ring?