Well the skew was expected in this mode.

@jurand for me the stills are incredible and way better than the canon t3i i used to have or gh2. Yes they are low megapixel but still over 4k and incredible dynamic range and full frame look. As well as usable high iso. II have never seen the problems you encountered. But then again i always use the real shutter and not the electronic one.

@Tatzu Don't expect a response from MikeLinn, it's just a link-bot.

I just spent 5 days with this camera. It was a video shoot. Its low light capabilities aren't a lie. We shot ina dark bar and didn't need any additional lighting and still came up with great noise free footage. tack sharp VF, Menus are more intuitive than stupid GH2's, REC video button is not ergonomic though. Other than that, build is very good, batt life good. The only question should be is do you need 4k? If you don't, this thing is a winner. I haven't looked at the footy on real monitors so unsure about aliasing and moire et all, didn't see any on a macbook pro.

I'm seriously considering upgrading to this camera instead of the GH4 (which I already have available to use if I want, as my fellow video-partner owns it), to live the thrill of going full frame and go beyond the dreaded 1600 ISO limit, but I'm not convinced by the colors. In almost all the video I saw online they look a bit strange to me, with a strong magenta tint and a strange rendition that makes them look artificial. Of course this is just my feeling.

Above post on color notwithstanding... I am thinking of switching from the GH4 to the A7s. (No, I cannot afford to run with both. :-( )

My main project over the next year is documenting a third-generation dairy farm now being run by the youngest daughter and other young women in upstate New York. Very interesting second year of transition to organic, grass-fed, women-run.

I've been using the GH4 the past two months and I am just getting creamed by high-contrast scenes, namely in barns with windows and large, doors or shooting into a trailer with open sides, etc. Below is a pretty typical situation (a still shot in RAW with shadow lift and a lot of highlight recovery). I have not metered the stop difference but you can see it:

Some on-camera lighting has been fine but large, stationary set-up isn't at all practical. I need to move a lot. I've adjusted some of my shooting but in terms of video, only shooting interior/exterior scenes on heavily overcast days means I miss a lot. (The barns are ringed with windows, so there isn't really a choice of angle that I could avoid hotspots...)

Planning to rent an A7s. Not expecting a panacea but very interested in being able to bring the ISO to where I need and have some highlight rolloff relative to the crushing I am getting in the GH4. I'm not feeling the need for 4k relative to dynamic range on this project. We'll see.

@flablo, one potential problem with colors is just user error. Picture Profile 7 defaults to S-Log2 gamma with S-Gamut color. S-Gamut is an extended gamut with more range mostly towards green. If you view S-Gamut footage without conversion by a matrix or a LUT, the footage will appear undersaturated. If you increase the saturation to compensate, the colors still won't be right, being shifted in CIE xy space. The shifting means colors are under- or oversaturated, and having the wrong tint. Standard color correction tools are unable to map between gamuts to fix this problem. Go check on some of the videos that you thought had bad color and see if they were using S-Log2. If there's no mention of a LUT in the workflow, they probably failed to convert colors correctly.

If you use an appropriate matrix or LUT for S-Gamut, this problem does not exist. Or you can set a custom picture profile with S-Log2 gamma along with a standard gamut like bt.709.

I find that the a7S's colors are quite good and accurate so long as the lighting is good. Under natural light and tungsten, the a7S's color is as good as any of my other cameras'. The a7S's color accuracy really suffers under some low-CRI fluorescent lights and metal-halide lights. Careful selection of colored optical filters can help under metal-halide lights. I've found no solution for fluorescent lights. I think all cameras have that problem to some degree, and I'm just more picky about color since getting the a7S and working in ACES.

@WalterH, S-Log2 is not a cure for high dynamic range scenes, but it will give you more options. Even when your camera is capable of capturing a large dynamic range, our displays are not capable of displaying them. So the high dynamic range scene needs to be mapped somehow to the small dynamic range of a display. I guess you already know this if you've done much work in Lightroom. For my video shooting, getting exactly the right exposure has been enough for me and mostly obviates the need for creative mapping of dynamic range. I just maintain a normal or slightly adjusted contrast curve, but with exposure compensation carefully applied in post thanks to S-Log2 and ACES. You can do creative mapping of dynamic range using curves, but it's challenging and I've never quite gotten the hang of it. It's certainly not as easy as the shadow and highlight tools in Lightroom, for example, which are awesome and let me get amazing HDR stills from a single exposure.

The a7S also has a bt.709-800 gamma setting. It's meant for standard bt.709 displays, but it captures 800% of the range of regular bt.709, with the extra range going into the highlights. That would be one option for HDR scenes if you prefer to set the exposure in the camera and not in post.

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That video about the Fotodiox Tough E-mount mod has been updated to say that the a7S already has an all-metal mount and doesn't need the mod.

@WalterH thanks for the feedback, I noticed the yellowish skintones as well. Somehow the colors reminded me of the colors from my GH3, and since the GH3 uses a Sony sensor... maybe there is a connection (?) @balazer amazing explanation! Thank you very much

The a7S has an all-metal lens mount and doesn't suffer from the wobble of other E-mount cameras, and so doesn't need the Fotodiox Tough E-mount mod. The Fotodiox video has been updated to note that.

@balazer Thanks for your very informative post about PP7 Slog-2 and S-gamut. There are still some questions I would like to ask you. What LUT do you use to convert S-Gamut color modes colors and where it can be found? I know that Sony has provided some LUTs for S-Gamut conversion, but they are aimed for F55/65. Are those LUTs still valid using with A7s? Also about the "ACES workflow" do you know if there is a good tutorial video that shows how the workflow goes in Resolve? I have had hard time getting the colors look good as well. Thanks.