Sony a7iv FULL FRAME (not crop) 50/60p UHD (4K) recording... Interesting??

[cyvideo]

Call me dense but I discovered something today by accident. I guess others may know this but I didn't so I learnt something.

I had been shooting with the Sony a7iv in 4K 50p which as most would know is in the APSC crop mode. At the same time, I was recording to an Atomos Ninja V and recording Prores at 4K 50p. All was working as expected. 4K 50p internal recording and going out to a 4K 50p external recording. I then needed some shots in HD. So I switched the internal record to, full-frame HD 50p. I was actually rolling when I noticed what was happening on the Ninja V. It was recording away quite happily recording the full-frame output from the 7iv. But to my surprise, it was recording a full-frame 4K 50p signal. On checking back I can confirm that if you are recording internally in full-frame HD set to 50p or 60p and have the HDMI output settings, not on "Auto" but set to "2160p" You can record the full-frame 7K downsampled image to 50p or 60p 4K externally. Further comparisons of the two external 2160p files recorded on the Ninja, one recorded when the a7iv was set to 4K internal Crop 4K 50p output and the other when the camera was set to HD internal full-frame 50p seem identical on the timeline. As my curiosity was triggered by this "discovery" further tests will take place.

Was anyone aware that you could do this? I can't find any Sony documentation regarding this capability.

Chris Young

P.S. EDIT.
This now makes me think that the a7iv is probably capable of recording FF 50/60p but Sony has restricted that capability.

 

[Peter C.]

That's interesting. I don't think there was any question this was an intentional cripple since the same processor and internal components are used in this camera as in their high end camera that are capable of filming without cropping in 4k 50/60

 

[ahalpert]

Hmm... but the 4K FF rolling shutter value is 26.8ms. Not fast enough for 50p

 

[NorBro]

Let me get this straight...

So you're saying you were recording 4K/50p in the camera and the recorder and it's cropped (as it should be), but then when you changed the camera to HD/50p (which you have to stop recording on the camera to do that), but you keep recording on the Atomos, you see the image on the Atomos zoom out during that change which appears as if it's recording full-frame? Is that correct?

Maybe it's HD but the text on the Atomos isn't correct because the software isn't sophisticated enough to change during recording?

Also, eventually you'll have to stop recording on the recorder, and the recorder should then show HD/50p no matter if the HDMI output is set to 4K because you're in the HD mode, yeah?

 

[cyvideo]

Hmm... but the 4K FF rolling shutter value is 26.8ms. Not fast enough for 50p

Fully agree.

Though how many people have been shooting with the a7iii, the Panasonic S1H (rolling shutter of 29.7 [ms]. The Canon EOS R6 full frame UHD 25fps rolling shutter 30.6ms with great success. Unless you are shooting material with reasonably rapid movement rolling shutter is not a major handicap in recording most normal human speed movement. For interview and the bulk of doco shooting it is not an issue. I've shot countless hours on the a7iii that's gone to TV without any issues whatsoever. Apart from some of the very latest stacked sensor cameras the above rolling shutter speeds are pretty much the go.

What my "discovery" means for me is that I can set the camera to FF HD 50p and the HDMI output to 2160p and record FF output in UHD 50p to the Ninja V. The bonus here for me there is that I can use my FF lenses to record FF 50p externally. I don't "have" to use APSC/S35 lenses to record 50p in those scenarios. As I said it was just a surprise to find this out. It only happens when you manually set your HDMI output to 2160p. Was only wondering if anyone else had experienced this behaviour before. Question? Does this also happen with the a7siii, the Ai etc. Just curious?

Chris Young

 

[cyvideo]

Let me get this straight...

So you're saying you were recording 4K/50p in the camera and the recorder and it's cropped (as it should be), but then when you changed the camera to HD/50p (which you have to stop recording on the camera to do that), but you keep recording on the Atomos, you see the image on the Atomos zoom out during that change which appears as if it's recording full-frame? Is that correct?

Maybe it's HD but the text on the Atomos isn't correct because the software isn't sophisticated enough to change during recording?

Also, eventually you'll have to stop recording on the recorder, and the recorder should then show HD/50p no matter if the HDMI output is set to 4K because you're in the HD mode, yeah?

NorBro. Let me clear this up somewhat. Set the a7iv to HD 50/60p in FF. You can't select UHD 50/60p in FF as you would be aware. Now set the HDMI out to 2160p in the external output settings menu. What comes out of the camera is a full frame UHD 50/60p output. If your trigger settings are correct between camera and Ninja V the Ninja will happily record the 50/60p output every time you hit record on the camera. Since I first posted we have now done a couple more tests and the Ninja V FF UHD 50p files from the a7iv look quite impressive on a new 55" LG C1 OLED. The FF 33 megapixel output in UHD 50p is a truly pleasing image to look at.

Sort of reminds me years back when Sony said there was no way due to hardware limitations that the Sony F5 would ever be able to record 4K... that was until an enterprising cameraman hacked his F5 to record 4K. The capability was already there in the camera. It just wasn't enabled. What happened? In short order Sony brought out a $999 4K firmware upgrade for the F5. Go figure? If the a7iv is capable of outputting FF UHD 50/60p I would suggest that the inability to do that internally was purely a market based decision. Who knows. Whatever, we are happy to have discovered this anomaly. Just hope that Sony don't do what they did with the A77 SLT when it came out. Right now I can't remember what the undiscovered feature was but when we upgraded the firmware the "undocumented" feature was no longer accessible.

Chris Young

 

[cyvideo]

That's interesting. I don't think there was any question this was an intentional cripple since the same processor and internal components are used in this camera as in their high end camera that are capable of filming without cropping in 4k 50/60

Yes. I'm starting to believe this might just be the case. Sneaky Sony, the Dark Force strikes again.

Chris Young

 

[cyvideo]

Additionally.

What I forgot to mention is that when using FF lenses in FF HD 50/60p you can of course have a function button programmed to jump to HD 50/60p crop mode. When you do this the external UHD FF 50/60p output will reflect that jump from FF to the 1.5 crop mode. Additionally, if you don't have the a7iv's remote trigger engaged to trigger the Ninja V and the Ninja is being triggered independently you can continuously record on the Ninja and record the jump from FF to Crop. Not that I need that but it's possible. That is something you can't do on the a7iv as you have to stop recording to select the crop mode from FF mode. You can of course still have the zoom programmed on the camera on a function button so that you can zoom in and out from FF to crop whilst recording. But that was possible even on the a7iii.

Chris Young

 

[Bassman2003]

Thanks for sharing your discovery. Are you sure there is not any kind of upscaling going on from the HD signal to meet the demand of the 2160 output requirement? Do you have a way to confirm the 4k50 is really form the 7k downsample?

 

[NorBro]

I have to be honest...I'm having trouble believing this.

I mean, I believe YOU, but it's not making sense unless it's a massive oversight.

Can someone else with a different Sony camera, maybe an a7SIII, confirm if you can send a 4K output to a recorder while in an HD mode internally on the camera? [Choose the 4K output, not auto, in the output settings.]

P.S. Sony does this with the sensors it supplies Panasonic to use so it's not new (the 4K/60p S35 crop).

 

[cyvideo]

Thanks for sharing your discovery. Are you sure there is not any kind of upscaling going on from the HD signal to meet the demand of the 2160 output requirement? Do you have a way to confirm the 4k50 is really form the 7k downsample?

No, At this point, I have no way technically speaking to state categorically that it is indeed the 7K downsample. My observation is based on the following. Sony specifically states that the FF 4K 25/30p is downsampled from the 7K sensor. All I can say at this point is if I pixel peep up to 400% I can see no difference in picture IQ from the external UHD 422 Prores at 25p (which we know is a 7K downsample going on Sony's statements) and the UHD 422 Prores at 50p. Obviously, there is a difference technically because the file size is much larger on the 50p file but visually the resolution, IQ and artifact cleanliness between the two files is indistinguishable. Specs-wise the 2160p25 and the 2160p50 file are 492 and 983 Mb/s apiece.

As you ask the question "Are you sure there is not any kind of upscaling going on from the HD signal to meet the demand of the 2160 output?" I have to ask "Why would Sony do that extra step of processing when they have a full 7K downsampling going on from the sensor? Technically it makes no sense to downsample from 7K to HD then re-upscale from HD to 4K. The 7K downsampling is obviously going on before the encoder so I think the downsampled 7K to 4K 50p steam is just directed to the 2160p output at the same time it is sent to the encoder. That would bypass any second stage downscale upscale steps. An extra step of upscaling would chew up a lot of extra processor time and processor capacity. Generally, Sony isn't into that kind of wasteful processing, quite the contrary. Also, I don't know or can't think of a case anywhere in my Sony experiences where two lot's of down then upscaling are involved. Look I may be totally wrong but if what you are saying is correct then I'm more than happy because whatever is going on the results we are seeing on the 55" LG C1 OLED are the best I have ever seen from a Sony mirrorless to date. Admittedly I haven't checked the a1 out like this. Would like to hear of anyone else's results on the a7siii and the a1 if they are inclined to give it a go.

Chris Young

 

[cyvideo]

I have to be honest...I'm having trouble believing this.

I mean, I believe YOU, but it's not making sense unless it's a massive oversight.

Can someone else with a different Sony camera, maybe an a7SIII, confirm if you can send a 4K output to a recorder while in an HD mode internally on the camera? [Choose the 4K output, not auto, in the output settings.]

P.S. Sony does this with the sensors it supplies Panasonic to use so it's not new (the 4K/60p S35 crop).

NorBro, and you think I'm not surprised at seeing this?

A colleague who was with me at the time said "No way that can be happening?" I agreed at the time but after the shoot before we packed up we did some quick checks and it seemed to confirm what we had observed. Further much more deliberate testing and analysis back at base have proved to us so far that we are indeed seeing a UHD 50p signal of a very high quality coming out of the camera when you select 2160p output. Which is not the default. I think it was "Auto". See my reply to Bassman2003 as I've explained what we have done so far to try to find out what is going on.

Sony oversight? Could well be. Just hope it doesn't get "shut out" with a firmware upgrade. Sony have done this before.

Chris Young

 

[NorBro]

Everyone patches up mistakes just like bugs, but this would be too much, ha...so silly if true.

The F5 situation was different; I would think that guy had programming experience or some guidance because what he did was unheard of, especially back then.

Maybe make a video about this if you'd like.

 

[cyvideo]

Further research... doh! i.e. reading the online ILCE-7M4α7IV help guide... helps explain the situation. If you want FF 50/60p output for FF lenses just set to FF HD 50/60p to be able to use either 50 or 60p frame rates out to 2160p on the HDMI output when it's set to 2160p. It just works! What else can I say? Obviously, you can output 50/60p UHD when the camera is in 50/60 Crop mode. Also, the color bit depth of 8 or 10-bit is reflected in the HDMI output dependent on the internal color bit depth you had previously selected, 8 or 10-bit. You can in fact even turn off internal recording and just record your 2160p out at whatever frame rate you have set internally in FF mode. Repeating, that 50/60p in FF is only available in HD.

Chris Young

https://helpguide.sony.net/ilc/2110/v1/en/contents/TP0003027244.html?search=hdmi

 

[NorBro]

ha, I actually read that page about 20 minutes ago but couldn't get much out of it without the camera in front of me.

IMO, the best part is getting the full view. If I owned and used that camera, I wouldn't care what's happening inside it as long as the 50p/60p is nice, passable, comparable to the 4K/24p/25p.

 

[cyvideo]

Everyone patches up mistakes just like bugs, but this would be too much, ha...so silly if true.

The F5 situation was different; I would think that guy had programming experience or some guidance because what he did was unheard of, especially back then.

Maybe make a video about this if you'd like.

Actually NorBro he wasn't a programmer just a thinking cameraman. It was Paul Ream from Extra Shot in the UK. Here is a refresher on how it happened. Check out Brian Hallett's 2014 video on this page.

https://www.provideocoalition.com/sony-f5-internal-4k-tutorial/

Chris Young

 

[cyvideo]

ha, I actually read that page about 20 minutes ago but couldn't get much out of it without the camera in front of me.

IMO, the best part is getting the full view. If I owned and used that camera, I wouldn't care what's happening inside it as long as the 50p/60p is nice, passable, comparable to the 4K/24p/25p.

Every bit as beautiful but at 50/60p NorBro. Suits me. It's always nice to pick up a little bonus morsel every now and again.

Chris Young

 

[NorBro]

Actually NorBro he wasn't a programmer just a thinking cameraman. It was Paul Ream from Extra Shot in the UK. Here is a refresher on how it happened. Check out Brian Hallett's 2014 video on this page.

https://www.provideocoalition.com/so...l-4k-tutorial/

Chris Young

I've seen it before, but no cameraman thinks that well, lol.

You have to know what you're looking at. You don't just open up code and start moving stuff around, you know? {Even if it's straightforward.}

But I know he's 100% a cam op/video guy, just saying.

That was cool stuff and one of the early signs of Japanese camera shenanigans. Although every company is no :engel017:

 

[ahalpert]

Fully agree.

Though how many people have been shooting with the a7iii, the Panasonic S1H (rolling shutter of 29.7 [ms]. The Canon EOS R6 full frame UHD 25fps rolling shutter 30.6ms with great success. Unless you are shooting material with reasonably rapid movement rolling shutter is not a major handicap in recording most normal human speed movement. For interview and the bulk of doco shooting it is not an issue. I've shot countless hours on the a7iii that's gone to TV without any issues whatsoever. Apart from some of the very latest stacked sensor cameras the above rolling shutter speeds are pretty much the go.

What my "discovery" means for me is that I can set the camera to FF HD 50p and the HDMI output to 2160p and record FF output in UHD 50p to the Ninja V. The bonus here for me there is that I can use my FF lenses to record FF 50p externally. I don't "have" to use APSC/S35 lenses to record 50p in those scenarios. As I said it was just a surprise to find this out. It only happens when you manually set your HDMI output to 2160p. Was only wondering if anyone else had experienced this behaviour before. Question? Does this also happen with the a7siii, the Ai etc. Just curious?

Chris Young

But I mean that a 26.8ms rolling shutter should only be able to complete 37.3 scans per second, not 50 or 60.

Sounds to me like it's not full readout, it's pixel-binned? I mean, I guess that was obvious. But it sounds to me like you're correct.. the camera should certainly be able to record pixel-binned 4k60p FF but Sony has handicapped it

 

[cyvideo]

But I mean that a 26.8ms rolling shutter should only be able to complete 37.3 scans per second, not 50 or 60.

Sounds to me like it's not full readout, it's pixel-binned? I mean, I guess that was obvious. But it sounds to me like you're correct.. the camera should certainly be able to record pixel-binned 4k60p FF but Sony has handicapped it

Yes, I think you are probably 100% right. Sony is doing it with their A1 with its 8K 48 Megapixel sensor, readout, though being helped by using a BSI stacked sensor. Cine D quote:

"Looking at 4K full-frame recording at 25 frames per second, the rolling shutter drops significantly to 8.1ms. Obviously, some sort of pixel binning is happening here – so it will be interesting to see if the dynamic range will benefit from shooting in the downsampled 4K full-frame mode vs. 8K full frame. In APS-C crop mode at 25fps, the rolling shutter is 11.1ms."
https://www.cined.com/sony-a1-lab-te...-and-latitude/

and we know Sony are 2x2 pixel binning four pixels to a bin with a 48 MP sensor in the a7siii to output as a 12 MP sensor with a very fast readout.

If we look at Canon's R6 we see a similar thing going on there. Again Cine D:

"In UHD 50fps full frame mode, the camera shows 15.3ms – hence, some subsampling seems to be happening to allow for 50 frames per second.

In crop mode (1.6x), at 25fps the Canon R6 exhibits 20.3ms rolling shutter – on the high end for a Super 35 sampling. In 50fps crop mode, a similar value to the result in full frame 50fps is obtained – 15.3ms."
https://www.cined.com/canon-eos-r6-l...-and-latitude/

and we know Sony is 2x2 pixel binning four pixels to a bin with a 48 MP sensor in the a7siii to output as a 12 MP sensor to obtain a very fast readout with its IMX510 sensor.
https://landingfield.wordpress.com/2...10-bsi-sensor/

Summing up, yes I think your observation is pretty spot on. Seeing that Sony is pixel binning on both the a1 and the a7siii I see no reason to think they are not doing so with the a7iv. Regardless of what's going on internally in the a7iv with its 2160p output it looks pretty decent for sure. Much like the pixel binned outputs from the a1 and a7siii. I'm guessing Sony is doing something similar to what's going on inside the Canon R6 but just not allowing internal recording. This again makes me think Sony has purposely held back internal FF 50/60p recording. It kind of makes sense to me. Given that the a7iv crop at 60p has a rolling shutter of 12.8ms I guess its FF 50p readout would be binned and maybe have slightly better figures than the Canon R6 where shooting UHD 50fps full-frame mode, the camera shows 15.3ms. Where some subsampling seems to be happening in the Canon to allow for that 50 frames per second. The numbers don't lie that's for sure.

Chris Young