Rumor: Sony A7s will have 4K video

dcloud said:
i dont need 4k but looking at 12mp 1.1x crop would make it resolute. Awesome. Same as gh4.
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Exactly. But with a 1.1x crop instead of 2.3x. And yes, as eoshd noticed, 1.1x is the same as you get with a NEX+speedbooster, and everybody considers that full frame (I had noticed too, I have a NEX+speedbooster) (he quoted exactly the same 4230x2820 sensor resolution that I posted in the first page here, I hope I'm not his inside source because I pulled that number out of my arse :D )

Now, since sonyalpharumors says the codec will be XAVCs, and it seems that only gets to 3840, then the 1.1x crop is basically settled.
What gets me excited here is that 1.1x crop is approximately what Sony DSLRs need in order to get electronic IBIS. And the fact that the "s" in the name seems to stand for "speed", which would mean this has a very fast sensor readout, and might be able to do, say, 1080p24 RAW video with a simple 2x2 binning, if Sony wanted to give us that (whic they probably won't).

In summary, this is poised to offer super-sharp UHD with 1.1x crop and a moderately good codec. It will probably have crazy high-ISO capabilities (like: clean ISO 12800).
Now I want to hear about bit depth, and about DR in video mode.
If the thing does 10bit (internally or externally) and has a log profile preserving all the DR from this monster-of-a-sensor, it's a winner. Like: the camera I've been waiting for.
 
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It's crazy how compact this stuff is getting, put a pancake on it and you have 4K in a pocket... I can't wait to see the DR on this thing.
 
Samuel H said:
Exactly. But with a 1.1x crop instead of 2.3x.
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This is where crop factors as currently defined (ratio of diagonals with FF 35mm) start to come unhelpful. Thinking of the 4k crop of the GH4 as 2.3x is true when referenced to FF35mm - but it may be more helpful to think of numbers relating to a crop down from the full frame of the format. (So it's much less than 2.3x crop of the full 4/3 frame.)

The other problem with the current definition is that it takes no account of aspect ratio - so keeping horizontal width the same, and going from 3:2 to 16:9 gives a smaller dioagonal and apparent crop. But is that the wrong way to look at it......?

Regardless, if you do think in terms of horizontals, then a 12 Mpix sensor must mean less cropping than one of 16 Mpix - which is good in video terms. But I suppose Peter is being robbed to pay Paul - a video improvement is coming at the expense of resolution in stills mode. Personally, I think it's a good compromise in a camera of this nature - and 12 Mpix is still reasonably good for stills mode.

Usage of a 3840x2160 crop doesn't just mean high quality 4k with minimised processing, it also must mean very good HD - derive each HD pixel from a 2x2 Bayer block. Exactly as the Canon C300 does. It means high quality with simple processing, and that means lower power requirements.
 
I came late to this discussion and spent the last hour reading it and checking the details. Really exciting stuff! I also red Andrew's article and found it objective, not written with a fanboy attitude, especially if you know his style... So, waiting for sunday to come!
 
harddrive said:
This is where crop factors as currently defined (ratio of diagonals with FF 35mm) start to come unhelpful. Thinking of the 4k crop of the GH4 as 2.3x is true when referenced to FF35mm - but it may be more helpful to think of numbers relating to a crop down from the full frame of the format. (So it's much less than 2.3x crop of the full 4/3 frame.)

The other problem with the current definition is that it takes no account of aspect ratio - so keeping horizontal width the same, and going from 3:2 to 16:9 gives a smaller dioagonal and apparent crop. But is that the wrong way to look at it......?

Regardless, if you do think in terms of horizontals, then a 12 Mpix sensor must mean less cropping than one of 16 Mpix - which is good in video terms. But I suppose Peter is being robbed to pay Paul - a video improvement is coming at the expense of resolution in stills mode. Personally, I think it's a good compromise in a camera of this nature - and 12 Mpix is still reasonably good for stills mode.

Usage of a 3840x2160 crop doesn't just mean high quality 4k with minimised processing, it also must mean very good HD - derive each HD pixel from a 2x2 Bayer block. Exactly as the Canon C300 does. It means high quality with simple processing, and that means lower power requirements.
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That's why I never look at the diagonal to calculate crop factors. I use the horizontal size only. 1.1x for the A7s (guessing 4230/3840) and 2.34x for 4K on the GH4 (36/17.3*4608/4096). It makes no sense that the crop factor (which I use to calculate equivalent focal lengths and equivalent f-stop for same DoF) changes depending on whether I'm going to keep 16:9 or crop for 1.85 or 2.40.

And yes, if this thing could shoot 1080p24 RAW internally with 2x2 binning, with all the DR and high-ISO awesomeness that I'm guessing the sensor will have, that's what I would shoot. If I have perfect 2K, I need better DR much more than I need 4K.
 
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Emanuel said:
Refrain your criticism gentlemen, please. He is an usual reader over these boards and we owe him respect as to any other human being on earth. Aside the fact, he runs one of the most successful corners on web dedicated to indie filmmaking, whether who likes him, whether doesn't. That said, I am used to read his stuff in a regular basis. And I am grateful for his work. As this community should be, aside his polemic character. To be honest, it doesn't bother me not even a bit. Internet would be a much more boring place without him.

E :-)


PS -- OK Christopher, I've just read where is coming from your criticism today and your corrigendum to his homework... In any case, Errare humanum est. The guy is a human, buddy ;)
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Nicely said.

Now back 2 Sony.

Andrew Reid said:
Some absolutely disgraceful personal comments here. Shameful.
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Just put it in another perspective. It's just a sign of jealousy on their part. There will always be haters. Just keep doing what you do.
 
Samuel H said:
Now I want to hear about bit depth, and about DR in video mode.[/SIZE]
[/SIZE]If the thing does 10bit (internally or externally) and has a log profile preserving all the DR from this monster-of-a-sensor, it's a winner. Like: the camera I've been waiting for.
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Yes. Lets hope. Can't wait for tomorrow.
 
The latest Metabones E-mount adapters cover full frame. EF-S lenses are APS-C that's what the text above is referring to.
 
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