Rumor: Sony A7s will have 4K video

paulcurtis said:
Hey Nirv, long time..

We should find out tomorrow. But £2400 is too much for this. I'm looking for a new stills so the A7 looks a better bet. I haven't been through the rest of this thread but IMHO

- 8 bit slog is problematic
- rolling shutter seem worse than usual
- 8 bit 4K is odd as well
(the RAW in these cameras is technically 8 bit too, but has a better compression scheme)

The DR will be the same as the rest no doubt, but stuffing that DR into 8 bit slog isn't making the best of it - bearing in mind the blacks are raised (loose 10% of your 8 bit immediately) and the highlight compression takes up a fair amount of space, so your usable range is more limited.

If Sony had made allowances for 10bit out at this price point then i would be more interested.

And of course have they sorted out the issue that affects the other models? Smearing flare in the A7 and shutter vibration (not so important) in the A7r. And whether it suffers the same range of issues with various wide angle lenses?

I hope i'm wrong, but sometimes what seems like a huge leap is quite incremental...

cheers
Paul
Click to expand...

Hi Paul

The same questions are going round in my head too. Slog in 8 bits, good luck.

It seems to be the ideal camera for those people who buy based on printed specs. Sony yet again it seems able to provide us with the camera that we really want at this price point. I'd quite like Compressed 10bit onboard like the Sony Z100 4K Video cam we'll probably have to wait for the next versions of the FS100/700 for that. Sony will no doubt do lots of jiggery pokery so as not to tread on too many toes of the F5 so, yeah, don't expect revolutionary leaps.

I see that it is now available to pre-order in the US for $2500 so in the UK it should be around £1800 inc VAT. I'd certainly pay that if the 35mm crop doesn't suffer from excessive rolling shutter as I'd quite like a stills/video camera for twatting about with on hols.

Does seem the perfect camera for time lapsing star trails....;)
 
DR is spec is stated to be 15.3 stops. Nikon D800 is DXomark measured at 14.4 in still RAW. DXomark DR measurement for RED Dragon is 14.8 with manufacturer spec of 16. the real question is how much of the still RAW potential will be usable in video mode.
 
henryolonga said:
I remember seeing an interview where they clamed it is a true world camera. Should be able to switch Frequency?
Click to expand...

My NEX-5N is not a world camera: it's the NTSC version and it only does 60p and 24p. Some guru (Philip Bloom, or Den Lennie, or someone like that) said the a7s would be the same, but truth is, this has changed with newer models. I learnt about it very recently, here. I checked the manual for my 5N, for the a7r, and for the a6000, and the newer models have an option for PAL/NTSC that doesn't exist on my 5N (what's weird is that if you go strictly by what it says on the manual, this option may not be there in NTSC models)

a7/a7r manual
PAL/NTSC Selector (only for 1080 50i compatible models): By changing the TV format of the device, shooting in a different movie format is possible.
Click to expand...

a6000 manual
PAL/NTSC Selector*: By changing the TV format of the device, shooting in a different movie format is possible.

* Only for 1080 50i compatible models. If you switch this selector, it will be required to format the memory card in the setting compatible with the PAL or NTSC system respectively. Also, note that it may not be possible to play back movies recorded with the NTSC system on a PAL system TV.
Click to expand...
 
Den Lennie said slog2 in the a7s seems to have the same DR as in his F5. If that's accurate, it's really impressive. From what I see here, recording on board (10:00 onwards), the F3 has nearly two stops better DR than the C300 (nearly half a stop on the highlights, about a stop and a half on the shadows). And the F5 should be slightly better than that (slog2 vs slog).

Yes, it's 8-bit, and if you spread it too thin you'll probably get banding and macroblocking and what not, once you add your contrast back. But that's theory, and in practice I don't see any issues in the (admittedly scarce) footage we have so far.

Same thing happened with C100: people -including me- complained about 8-bit only, but in the end the image is clean and that's all that matters.
 
Some questions about DR and 8-bit:

When you compress alot of DR into 8-bit, that means that the physical difference between the darkest and brightest part of the subject get recorded as being relatively closer to each other than a camera with less DR right?

So what the S-log will do is to squeeze alot of information into the limited luminance and chroma-range?

Would this result in a very flat image when the subjects physical properties are not very big in contrast, but a constrasty image if the subject were very contrasty (pushing the sensor DR)?

Would not this mean that you could dial in the curve prefered for a specific subject and never really record a super-flat image?
 
stokstad said:
Would not this mean that you could dial in the curve prefered for a specific subject and never really record a super-flat image?
Click to expand...

When you are recording 8 bits it's always preferable to choose the closest look in camera to the finished grade. There simply isn't the data available to unpick a crunchy gamma curve or pile on oodles of contrast in an overly flat image.

It also depends a lot on how the 8 bits are used when recording, it was quite a trend in the FS100 forum to shoot with a raised black level to give a faux log look. This wasn't a problem because it was just an offset to the data and you didn't lose any of your 8 bits but if SLog2 behaves as Paul Curtis suggests then it might not be without issue. The proof of the pudding will be in the eating with Slog in 8 bits it's not something I'd get overly worried about. By choosing an appropriate gamma curve for the shooting conditions which has a pleasant white roll-off and nicely exposed should give you an excellent image to work with in post.
 
Samuel H said:
My NEX-5N is not a world camera: it's the NTSC version and it only does 60p and 24p. Some guru (Philip Bloom, or Den Lennie, or someone like that) said the a7s would be the same, but truth is, this has changed with newer models. I learnt about it very recently, here. I checked the manual for my 5N, for the a7r, and for the a6000, and the newer models have an option for PAL/NTSC that doesn't exist on my 5N (what's weird is that if you go strictly by what it says on the manual, this option may not be there in NTSC models)
Click to expand...

Be that as it may but this time it came from Kanta Yamamoto a Sony Japan representative at NAB. Check the video I linked in my previous post.
 
I think it is very unlikely that all these 15 stops of DR go down the s-log path.
Not just unlikely but also counter-productive. If all the DR is there it is probably compressed at the shadows end (and possibly in the highlights).
 
Ian-T said:
Nice video. I saw this earlier...looked like a long commercial. Reminded me of the sample Sony A7s promo. DR looked good. Didn't you just sell off your BMPC 4K camera? I was this far on purchasing it and picking it up directly from you in Orlando. But videos like these keep pushing me towards the GH-4.
Click to expand...

I did sell it...the GH4 smokes BMPC ProRes for my needs (narrative film, a lot of low key, FPN nightmare with BMPC...and mine was one of the ones with low FPN). The BMPC was just too risky to use on a professional gig & I need more than ISO 200.

GavinAbe said:
My feeling is that both cameras will have there place each with the strengths and weakness, In my case the G4 is more in line with my needs , for 1, the A7s needs an external drive to record $k where as the g4 not , the money I would need to spend on a external drive, I would rather use that money towards a new lens or even the grip on the G4.
Click to expand...

Absolutely. I'm still going to pick up an A7S, but honestly I'll probably keep the GH4 as well for portable & discreet 4K without a bulky setup.
 
So if s-log2 is the same s-log2 as in the other cameras we should be looking at around 13 stops.
With 90% white at around the middle of the value range (and the top half of the range used for the 3-4 stops superwhites) this camera will likely need consistent overexposure for decently fat and clean mids (when s-log is shot). Hopefully there is enough curve control for customizing a good looking fat mids gamma.
 
I'm willing to bet 14-15 stops. Den's stuff looks at least as good as dual ISO raw from the 5DMK3 which is around 14 stops.
 
Not sure that this would be good if it is true.
One of the clever things with Canon log is that it is not log at all at the black end. Neither are Arri log or s-log, for that matter as it doesn't really make sense, but this is most pronounced with Canon's curve. S-log is flatter than Canon log, and s-log2 is flatter than s-log. And Canon log is probably already on the edge of what is sensible with 8 bits.
The last thing I want to see is crappy Cinestyle-like footage with no detail and butchered mids after expansion. I would prefer to have the in-camera means of designing a good WideDR style gamma to get the max out of the camera in 8 bits.
I must admit I don't like the log sample of the A7s (the Scotland one) - it looks to be breaking or on the verge of breaking. Shooting 4k s-log2 for 2k delivery should help a lot though.
 
So, with such a wide profile, a bigger real-world brightness range gets squeezed into the 256 values of the 8-bit codec. Then, in post, you add a levels filter to redefine input points (get rid of unused blacks and whites, stretching the histogram horizontally), then a curve to reassign contrast where you want it. You'll probably have around 20-25 brightness values per stop of light in the midtones, and that's a really low number. But if the codec is good then these issues can be minimized (the biggest problem with cinestyle is that once you add contrast back you start to see horrible macroblocking in well-exposed skin tones). And in any case: there is such thing as "too flat", but the proof is in the pudding. I don't care how many theoretical problems this has, as long as I don't get issues in practice. We'll see...
 
Last edited:
cpc said:
The last thing I want to see is crappy Cinestyle-like footage with no detail and butchered mids after expansion. I would prefer to have the in-camera means of designing a good WideDR style gamma to get the max out of the camera in 8 bits.
Click to expand...

The camera has Cine1-4 plus 709 800% which should be more than adequate.

SLog2 is included to save the faux Log crowd the bother.
 
You must log in or register to reply here.
Back
Top