BasiliskFilm

I think you are probably right that it is a bit of a myth that cameras have an intrinsic "motion cadence". There are a range of problems with shooting motion: incorrect frame rate conversion, wrong shutter speed, rolling shutter artefacts, jittery lens/sensor stabilisation; some of these come in the class of user error, or can be avoided by the skilled operator. Once these are ruled out, most cameras actually record motion in a very similar way, and I would be surprised if many could spot the difference at 24 fps.

Now that third party lens support is coming through from Sigma and Tamron, a budget conscious purchaser can just concentrate on the quality of the body, and not worry about being stung on the glass. OK it is a shame that fast compact lenses optimised for mirrorless are taking their time, as the Sigmas are bag fillers. But now it is not just about size - mirrorless is the value, quality and usability option for full frame video.

If you want heavily cropped video, surely the Panasonic route would make a lot more sense? You can't even use a focal reducer on the 5D mkIV

Most folk who shoot 30 minute+ takes are doing it in quite specialised circumstances. If you are leaving a camera on a tripod pointing at a speaker on a platform and pressing record there are 100 other video cameras that can do a decent job. Who shoots more than half and hour shallow DOF video? I am trying to think of the last time I shot more than a minute of anything.

It seems that the video performance might be similar to the A9. Has anyone tested digital zoom on that camera? In theory for 1080p shooting a 1:1 pixel readout would give up to 3x zoom without significant loss of quality. If that is also true for slow motion shooting, then this could open up a lot of options for shooting action, without having to shell out for the largest lenses, maybe even with primes, and using digital zoom to frame.

It's a quick-and-dirty way of comparing rolling shutter in different modes. I am sure that someone will do the maths to compare them more accurately, but if you have seen these tests before you can already tell that Sony continue to improve the readout speed of their sensors. Full sensor readout of a 24MP FF sensor has only been done on the A9 before so it is a considerable challenge on a $2000 camera

Albert Dros has done a rolling shutter test. Obviously full frame 4K is worst, but this is reading all 24 MP, so all things considered, not too bad. The other modes (4K crop, 1080p) are pretty good, and given that hand-held is sensor stabilised, visible rolling shutter should be avoidable.

One thing this camera does for sure is make some of the others look a bit pricey. Up to now the A6500 looked like the most affordable full featured model, now you can get a seriously better body and full frame for 50% more; they are even chucking in a kit lens half price at £200 extra which can't be bad.

I would assume there is a level at which the hardware of the A9 and A7III are significantly different, particularly on the sensor readout rate, which partially justifies the higher price of the A9. It is possible this translates to less rolling shutter on the A9. It is certainly a bit un-Sony to deliberately cripple a model so it is possible the lack of picture profiles is a hardware limitation; as you say the A7III will even more effectively cannibalise sales of video cameras than the A9 so there is no logical reason not to implement them on the A9 if it can be done.

Need to see figures, but assuming that S35 mode on the A7III will have 1:1 pixel readout for 4K, which could be significantly faster than the 6K downsample from the whole sensor. So if you want minimum rolling shutter, and extra reach for action, then crop mode might be a good option.

True, speedboosters get you closer optically, but move you further away in terms of size and weight equivalence. And if we are talking native lenses then AF might be an issue.

Ain't no true equivalent to a full frame f1.4 lens on m4/3

The 105 f1.8 might be a great lens. If you stop it down you will get heptagonal highlights, with only 7 blades. If you want to shoot at f2.5 then the classic 105 f2.5 AI/AIS might be a better, cheaper and lighter option, with the same 52mm filter thread that the 50mm f1.2 has. It has the advantage, as a stills lens, of being usable with the OVF focus screen at full aperture. Anything faster than that and you probably need to switch to live view to be sure of focus as the focus screen is optimised for f2.8 zooms (unless they have improved in current models)

The end of King Kong would have been epic in vertical widescreen - the whole of the Empire State, plus monkey!

The resolving power of the 24-120 on that 42 MP sensor looks pretty amazing. Not saying that the Canon is worse, but there does seem to be some future-proofing going on in the Sony lenses, and there is that 100+MP shift sensor mode already. On the other hand if you are using the A7S then it might be resolving stuff you are never going to see

My guess is that the full frame 4K will be at least as good as the A99II, maybe the D850, which is much improved over the A7RII.

I can be powered by USB - is that new? That should provide some options.

Is the video AF useless for anything other than stationary objects? Sounds like the AF/EVF/OIS make the Sony cameras much more flexible for video, and if the A7III gets the full frame 4K image right as well, at a reasonable price, then it will be hard to justify getting the 850 unless you need the top class stills performance.

I suppose 6K at 30p is roughly the same data volume from the sensor as 4K at 60p so that might be do-able. Wouldn't have true 4K at S35 though, which is a popular feature.

If the A7III lives up to rumours (full sensor 4K readout, class leading autofocus) what is left for the A7SIII? Just see-in-the-dark capabilities? (I don't suppose the A7III will be shabby in low light). Perhaps a 12 MP sensor will allow for 4K60p internally? Otherwise it is hard to see a lot of people opting for it.

Because for video, you might as well buy a micro 4/3 camera, with lenses designed for the format?

Looks like it is "good enough" to keep someone invested in Nikon glass, shooting stills and video, on-board. Unlike the 5D Mk IV, which seems to be moving in the wrong direction. Nikon users are also a bit more "trapped" as their lenses don't lend themselves well to adaptation to Sony. For someone starting from scratch looking for the best full frame video option, then Sony is probably the way to go.

I guess the drawbacks for long term reliability are that the adaptor moves the whole lens (especially with heavy lenses) and that you use the same motor for driving all the lenses (unlike AF lenses that each have their own motor) so it would not be surprising if it wears out more quickly. Nice idea though. I would be surprised if it can track motion smoothly enough for video though.

That's what the 42 MP sensor is for? A full downsample from 8K to 4K seems to be beyond current processors, but at least line-skipping gives a tidy 4K matrix of pixels, even if the gaps can lead to more aliasing. The 4K full frame out of the A99II seems fairly clean, when in theory it should be roughly the same as the A7Rii - is there some clever voodoo going on there then?

If it matches the video of the A99, also has decent AF, and lets folk use their Nikon glass natively, that would be an decent option for those invested in Nikon glass. On the other hand if they brought out a video oriented D750 upgrade, 24 MP full frame sensor down sampled to 4K (A9 style) for half the money, then you can keep the 40+ MP camera.