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Advice Needed on A7Siii and External Recorder


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Ultimately, I need to record at 4K, 120, 4:2:2.  I can't compromise on that. 

 

I know that I need the CFexpress card to do so internally.  But the 160 Gig card is $400.  It's not cheap so I was thinking that perhaps I should just go with an external recorder like the Shogun so that I can have a harddrive, along with the monitor and XLR inputs.  Yes, this is $1200 but that's why I'm looking for advice.  Im confused as to the Shogun's recording.  It's listed at 4K, 60, 4:2:2, but someone told me that their recent firmware upgraded the 60 framerate to 120....so it will be able to record exactly at the settings that I need.  But does the A7siii output at these settings, or can it only record internally at these settings?

 

My other issue with the CFexpress card is the size.  If Im recording internally at 4K, 120, 4:2:2, with the highest codec, how many minutes can I record with 160 Gigs?  

 

Any advice is greatly appreciated.  

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I think you'll have to learn reading the fine print, and not to believe all hearsay or marketing hype.

For instance: Sony itself claims the 

Quote

Full-frame 4K recording at 120p6

involves a "10% crop". (Click on the "6" footnote at the end of that heading). It's up to anyone's guess wether that is a 10 % crop at the overall pixel count, of if it's applied to both width and height of the image. In the latter case, that would amount to a 19% loss already.

The same sources quotes the

Quote

16-bit RAW data output

via HDMI at a maximum of 60fps. "Compatible recorders to be announced. (As of July 2020, Atomos Ninja V is expected.) See footnote 10 for that.

Additionally, the help guide for the A7S3 lists the maximum duration for a recording at 600M on this page. Note, that even at 600M the maximum frame rate is posted as 60p.

Finally, unleashing a factor of two (in the recordable frame rate) simply by means of a firmware update, without increasing the power of the underlying hardware, seems extremely unlikely to me.

Remember: if something sounds too good to be true, it probably isn't.

 

 

Edited by Chrissie
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Your reply in no way answers OP's questions @Chrissie. You're raising all kinds of arguments against the use of 4k120p that may be totally irrelevant to OP:

5 hours ago, mkbigmoz said:

Ultimately, I need to record at 4K, 120, 4:2:2.  I can't compromise on that.

The maximum bitrate at 4k/120p 10 bit 4:2:2 is 280 Mbit/s or 35 MB/s (H.265 XAVC HS codec). A 160 GB card can record 4571 seconds at this bitrate, or 1h:16min. This is a much lower bitrate than 4k/60p 16 bit (600 Mbit/s), so I don't see why an external recorder couldn't handle this. Might need a firmware update though.

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1 hour ago, Pieter said:

that may be totally irrelevant to OP

@Pieter: quite to the contrary. I took the initial statement of the TO, that he "can't compromise on that" at face value. The very notion of "no compromise" doesn't lend itself to any - well - compromise. 😉 

I pointed out, and backed this with quotes from Sony's original documentation, that Sony

  • admits to compromising in the question of "full 4K" already
  • is inconsistent about its claim the A7S3 can do 120fps at all. One could have expected, that such a main feature would have found its way into the documentation, if it existed at all.

If the prospective initial recording device (Sony A7S3) can't even record at the full specs which the TO "can't compromise" on, then there is no point in discussing the secondary question of wether the A7S3 might be able to output at full specs, which it couldn't record at in the first place.

Let alone the tertiary question, if the prospective external recording device might be able to record at full specs from a source, which couldn't ...

I'm fully aware, that the TO would have preferred a statement which confirms his initial plans. I'm also fully confident, that he will be better off, both financially and result-wise, if a prerequisite, which he took for granted, gets some more scrutiny due to reasonable doubt.

If that's not relevant in your view, then I couldn't care less. Because that's the way proper requirements analysis has to be done.

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Maybe it's time to look towards a different camera.

You can't expect a dump truck to fly no matter how long a solution takes, Re: "Might need a firmware update though." and 4K really isn't 4K if it goes into crop mode Re: "Involves 10% crop".

Well thought out and documented points brought up here but in the end It might be time to grasp that you can't plow 20 acres with a butter knife if "4K, 120, 4.2.2 can't be compromised" and find a different device to get you to where you need to be. Seems to me 7Siii can't reasonably hit all the points you require unless you start throwing money at it and tacking on additional hardware. 

This isn't the first time 4k, 120, 4.2.2 has been shot by anyone has it? It begs the questions 1) How was it done before now? and 2) What was used to capture it? If you need to fly trying to do so in a dump truck merely because you have one isn't the best or only option. It's like making the introduction, "Mr. Square Peg meet Mr. Round Hole."

 

 

Edited by VTC
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6 hours ago, Pieter said:

Your reply in no way answers OP's questions @Chrissie. You're raising all kinds of arguments against the use of 4k120p that may be totally irrelevant to OP:

The maximum bitrate at 4k/120p 10 bit 4:2:2 is 280 Mbit/s or 35 MB/s (H.265 XAVC HS codec). A 160 GB card can record 4571 seconds at this bitrate, or 1h:16min. This is a much lower bitrate than 4k/60p 16 bit (600 Mbit/s), so I don't see why an external recorder couldn't handle this. Might need a firmware update though.

 

Thank you for the responses.  I apologize, but I should have clarified that I'm fine with the 10% crop.  I knew that going in.  I'm not willing to compromise on the 4K or the 120 frame rate.  Your point about the bitrate (16 vs 10) is exactly why I'm confused.   I'd like to record 4K, 120, 4:2:2 with a 10% crop on an external recorder with the a7siii.  

 

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5 hours ago, VTC said:

4K really isn't 4K if it goes into crop mode Re: "Involves 10% crop".

How is it not really 4k if a crop is involved? 4k only needs 8.3 MP's, so the 12 MP sensor of the A7Siii has pixels to spare. This also relates to Chrissies point: in full-sensor readout the A7Siii downsamples from 4240 by 2385 pixels (10.1 MP) to 3840 by 2160 pixels (8.3 MP). In 120p-mode it reads directly from 3840 by 2160 pixels, hence the 10% crop (1 - 3840/4240 = 9.4%). So yes, it uses about 18% less sensor area in 120p than in 60p but still uses real 4k input.

Edited by Pieter
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On 9/26/2020 at 1:23 AM, Chrissie said:

I think you'll have to learn reading the fine print, and not to believe all hearsay or marketing hype.

For instance: Sony itself claims the 

involves a "10% crop". (Click on the "6" footnote at the end of that heading). It's up to anyone's guess wether that is a 10 % crop at the overall pixel count, of if it's applied to both width and height of the image. In the latter case, that would amount to a 19% loss already.

Remember: if something sounds too good to be true, it probably isn't.

Uh, what? 1.1x crop for 4k120p is hardly a compromise in a camera that costs $3500 USD and is as good as this one is for that money. You're still getting pixel-for-pixel UHD 4K, the crop refers to 10% crop into the full frame sensor size, not a crop into the original picture's resolution.The resulting image is still without pixel binning or noticeable loss in quality, just a 1.1x crop on your focal length. Compare this to any of the competition who for more money cannot even do 4k at 60fps without a full 1.5x APS-C crop (S1H) or the EOS R5 which cannot do it for more than a few minutes without overheating and needing 20-30 minutes powered down to do it again. 

 

 

As for the OP's question, there are no recorders that can achieve the recording of 4K @ 120fps externally via HDMI, unfortunately. It's a limitation of HDMI 2.0 which all currently shipping monitor recorders are equipped with. The camera itself now has HDMI 2.1, but will remain to be seen whether that actually does make it possible or not. I doubt it for a product this early in the HDMI 2.1 ecosystem. 

The best you can do is use an Atomos Shogun Inferno, Shogun 7, or Ninja V to get yourself 4K 4:2:2 up to 60fps in ProRes, and then record internally to V90 SD or CFExpress A for the times that you need 120fps at 4K.  You can still monitor the 120fps of course on your Atomos, but the camera will need to record the 120fps. Note you don't even really need the CFExpress cards to do the job. A V90 SD card will get you every recording mode and framerate except S&Q mode, which is the recording mode where the camera will record an already-slowed-down version of the clip with no audio. I don't see the need for this personally when you can still record 4K 4:2:2 120fps to a cheaper v90 SD, with sound and slow it down in post. You could feasibly do all internal recording and use a cheaper non-recording monitor like the Atomos shinobi or something, but IMO having the ProRes and cheaper PC SSDs for media is so valuable even if it does not go all the way to 120p. 

 

And finally, if you're looking for ProRes RAW, note that the only currently released recorder that can do it is the Ninja V. Huge disappointment for me as the owner of two 7" Shogun Infernos to see that there isn't a 7-inch RAW recording solution out there, as I don't like the 5" size. Not even the new Shogun 7 will be doing it, as confirmed to me by Atomos who claim only the Ninja V has the hardware to take in RAW via HDMI. I've been recording ProRes RAW for quite awhile from other cameras via SDI on my monitors, but HDMI I guess is a different story. I'm gonna hold out and keep on using ProRes 422/422HQ/4444 on my Shogun Inferno until they hopefully and eventually do release a RAW-recording 7" monitor. 

 

Edited by fs454
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3 hours ago, fs454 said:

Uh, what? 1.1x crop for 4k120p is hardly a compromise in a camera that costs $3500 USD and is as good as this one is for that money. You're still getting pixel-for-pixel UHD 4K, the crop refers to 10% crop into the full frame sensor size, not a crop into the original picture's resolution.The resulting image is still without pixel binning or noticeable loss in quality, just a 1.1x crop on your focal length. Compare this to any of the competition who for more money cannot even do 4k at 60fps without a full 1.5x APS-C crop (S1H) or the EOS R5 which cannot do it for more than a few minutes without overheating and needing 20-30 minutes powered down to do it again. 

 

 

As for the OP's question, there are no recorders that can achieve the recording of 4K @ 120fps externally via HDMI, unfortunately. It's a limitation of HDMI 2.0 which all currently shipping monitor recorders are equipped with. The camera itself now has HDMI 2.1, but will remain to be seen whether that actually does make it possible or not. I doubt it for a product this early in the HDMI 2.1 ecosystem. 

The best you can do is use an Atomos Shogun Inferno, Shogun 7, or Ninja V to get yourself 4K 4:2:2 up to 60fps in ProRes, and then record internally to V90 SD or CFExpress A for the times that you need 120fps at 4K.  You can still monitor the 120fps of course on your Atomos, but the camera will need to record the 120fps. Note you don't even really need the CFExpress cards to do the job. A V90 SD card will get you every recording mode and framerate except S&Q mode, which is the recording mode where the camera will record an already-slowed-down version of the clip with no audio. I don't see the need for this personally when you can still record 4K 4:2:2 120fps to a cheaper v90 SD, with sound and slow it down in post. You could feasibly do all internal recording and use a cheaper non-recording monitor like the Atomos shinobi or something, but IMO having the ProRes and cheaper PC SSDs for media is so valuable even if it does not go all the way to 120p. 

 

And finally, if you're looking for ProRes RAW, note that the only currently released recorder that can do it is the Ninja V. Huge disappointment for me as the owner of two 7" Shogun Infernos to see that there isn't a 7-inch RAW recording solution out there, as I don't like the 5" size. Not even the new Shogun 7 will be doing it, as confirmed to me by Atomos who claim only the Ninja V has the hardware to take in RAW via HDMI. I've been recording ProRes RAW for quite awhile from other cameras via SDI on my monitors, but HDMI I guess is a different story. I'm gonna hold out and keep on using ProRes 422/422HQ/4444 on my Shogun Inferno until they hopefully and eventually do release a RAW-recording 7" monitor. 

 

Really appreciate the time you took in the post.  Very informative.  In regards to the V90 SD card, what is the minimum read/write speed that this card needs to be to record 4K, 120, 4:2:2?

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  • 3 weeks later...

My brand new A7S3 hits 120 fps 422 effortlessly with a Lexar V60 card.

Was planning to get a CExpress card but found it too expensive. I chose to go the Ninja V way with far far cheaper SSD cards, I got 4TB for about $500, while the SONY 128GB SF-G TOUGH SERIES UHS-II SDXC MEMORY CARD costs me a dear $ 220! 

Hooked the A7S3 with my Ninja V and was outputting PRORES RAW 4K @30p 

It cannot get any better because one does not even need RAW all the time, but getting 10 bit ProRes is the real treat! Since I do a lot of outdoor Docu shoots and cycle tours, I really like the small 5" Ninja V + A7S3 to any other camera or the larger recorders.

 

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