A7RIi vs A7SII - going crazy, cannot choose

[NorBro]

A little off-topic, but just wondering...why are you able to record 4K in APS-C with the A7S (via external recorder) and not internally in APS-C with the A7SII?

 

[DLD]

A little off-topic, but just wondering...why are you able to record 4K in APS-C with the A7S (via external recorder) ...

You can't. Not enough pixels for 4K in the s35 crop in A7s (12.2 MPX sensor).

 

[DLD]

By the way, B&H (and I assume other retailers as well) are offering major discounts on A7RII. Free Metabones EF to E adapter and (or and/or?) a $200 in-house rebate. Given that it's been a top seller since its release, this is a darn good deal.

 

[Samuel H]

The SD speed limit of the a7R II is 36 MB/s

With 14-bit RAW, you'd need 2.3:1 compression to fit 1080p24 in that footprint. Make it 10:1 and you can fit 4K at 24 fps, no audio.

In any case, I don't think the camera has the processing power to do RAW compression, and, if it had, I don't think Sony would be willing to canibalize itself so badly.

 

[NorBro]

You can't. Not enough pixels for 4K in the s35 crop in A7s (12.2 MPX sensor).

I believe you can and it has something to do with upscaling the image via an external recorder?

https://vimeo.com/115426572

 

[Jim Ritscher]

And, then there's Sony's historical lack of firmware upgrades, which are really only issued in the form of new camera bodies.

Funny. And alarmingly true.

 

[DLD]

I believe you can and it has something to do with upscaling the image via an external recorder?

Ya but that's not a "real" 4K. Whether one can tell the difference between "real" and "upscaled" is another matter. On chart tests, an 8.8 MPX GH4 delivers about 1,500-1,550 lines of resolution. DVX 200 which oversamples 4K from 13 MPX can get about 2,000 and, to get to 2160, one would probably need 17.6.

ARRI Alexa upscales to 4K internally from its 5.7 MPX "open gate" but Netflix still doesn't accept it as a 4K camera, since theoretically, anything can be upscaled. All 4K TV do it too.

 

[NorBro]

Thank you. Yea, I was just wondering more of why can't the A7SII upscale it in camera...but on another side note...if the A7SII ever shot RAW externally to an O7Q, that would be the most amazing thing ever.

 

[blafarm]

A little off-topic, but just wondering...why are you able to record 4K in APS-C with the A7S (via external recorder) and not internally in APS-C with the A7SII?

I believe the original A7s upscaled APS-C 2.7k -- to 4k with an external recorder connected.
If I am not mistaken, this APS-C upscaling feature has been removed from both the internal and external recording capabilities of the A7SII.
It's too bad, as this feature could occasionally come in handy.

 

[DLD]

Thank you. Yea, I was just wondering more of why can't the A7SII upscale it in camera...but on another side note...if the A7SII ever shot RAW externally to an O7Q, that would be the most amazing thing ever.

The first step for A7SII and A7RII would be to send "real" 10-bit signal out via the HDMI. Now, that should have been possible since GH4 (sort of) does it at a much lower price point. It'd have more upside for the A7RII (more pixels, more information) but Sony must have decided not to compete with its own FS5 and FS7 cameras in this instance.

And, as a side note, "true" 10-bit recorded into a high bit rate ProRes externally would be basically indistinguishable from Raw. The "real" 10-bit out or the (highly) compressed internal Raw is probably the next step for the sub-$10,000 models from the major manufacturers. Black Magic Design has it in their URSA line already.

 

[NorBro]

Blackmagic has it in all of their cameras. That's why I would love it so much because I come from that world. And to have it on the A7S would open up new possibilities with the low-light capability.

And there is definitely a difference in RAW and ProRes if we're talking post flexibility. You can manipulate a Cinema .DNG in ways you could never touch a regular ole .mov ProRes file.

 

[DLD]

... And there is definitely a difference in RAW and ProRes if we're talking post flexibility. You can manipulate a Cinema .DNG in ways you could never touch a regular ole .mov ProRes file.

There's an overlap that depends on the type of ProRes and the compression of the Raw file. As has been explained to me on another thread recently, anything beyond 2/2.5 compression produces a lossy image. I surmise that anything shot in a 6/1 or greater won't be as good as ProRes 444 XQ, which is roughly a 3:1 lossy compression.

As to getting true lossless Raw out of the camera, BMD does have it. Now, let's look at the recording bit rates (off B&H Ursa page). Here, ProRes444 XQ exceeds both 3:1 and the Uncompressed Raw! And here my knowledge of codecs and the photon physics ends as the differences have to lie at the core of Cinema DNG and ProRes.

-------------------------------

4000 x 2160:
CinemaDNG Raw - 265 MB/s
CinemaDNG RAW 3:1 - 125 MB/s

3840 x 2160:
Apple ProRes 444 XQ - 312.5 MB/s
Apple ProRes 444 - 165 MB/s
Apple ProRes 422 HQ - 110 MB/s
Apple ProRes 422 - 73.6 MB/s
Apple ProRes 422 LT - 51 MB/s
Apple ProRes Proxy - 22.4 MB/s
--------------------------------------

 

[NorBro]

And here my knowledge of codecs and the photon physics ends as the difference have to lie at the core of Cinema DNG and ProRes.

haha...yea, sometimes I feel like you may not actually use any of the cameras you post about, but you are a true library of information and I enjoy your posts!!

Working with RAW metadata is a different world than working with ProRes files no matter what the bit rates are.

 

[DLD]

haha...yea, sometimes I feel like you may not actually use any of the cameras you post about, but you are a true library of information and I enjoy your posts!!

Working with RAW metadata is a different world than working with ProRes files no matter what the bit rates are.

Thanks. My logic is that there has to be a reason for 444 XQ to have such a high bit rate or people would just record the Uncompressed Raw. Most big budget TV shows that use Alexa were partial to 4:2:2 HQ anyway. In 2K!

(now I am going back to my webcam)

 

[jurny]

it' prores 4444 not 444. DNG has 3 channels. RGB. prores has 4 channels RGBA. Alpha channel is your Higgs Boznon

 

[NorBro]

Inside the ProRes white paper it's 4444, but when they talk about it they say 4:4:4 sources, and inside the URSA it's 444 too. It's like they drop the alpha channel...


EDIT: Do they?

 

[DLD]

Inside the ProRes white paper it's 4444, but when they talk about it they say 4:4:4 sources, and inside the URSA it's 444 too. It's like they drop the alpha channel...


EDIT: Do they?

https://larryjordan.com/blog/what-is-prores-4444-xq/


So, 4444 extends beyond 10-bit into 12 and 16.

Good night, Gracie.

 

[yoclay]

My experience is that there are not a great deal of differences between Prores 4444 and RAW, even Proress
422HQ is pretty darn close. Yes, for green screen and compositing it can make a difference, but for all the rest, Prores is largely sufficient.

 

[paulcurtis]

My experience is that there are not a great deal of differences between Prores 4444 and RAW, even Proress
422HQ is pretty darn close. Yes, for green screen and compositing it can make a difference, but for all the rest, Prores is largely sufficient.

The huge difference is RAW is pre white balanced generally whereas ProRes is white balance baked in. This can make a huge difference in the grade as well as enable techniques such as highlight recovery (which really requires RAW data). In other words you can get more range from RAW.

cheers
Paul

 

[DLD]

The huge difference is RAW is pre white balanced generally whereas ProRes is white balance baked in. This can make a huge difference in the grade as well as enable techniques such as highlight recovery (which really requires RAW data). In other words you can get more range from RAW.

cheers
Paul

What about the compressed Raw? Say, 3:1, as shown in that URSA spec sheet, or even the greater compression as possible in Red's 6:1, etc?