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Every factor 4:2:0 affects


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#1 Macks Fiiod

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Posted 16 February 2016 - 02:54 PM

I recently got a camera with healthy dynamic range (Sony F3) and have been shooting 422 with external drive. Sometimes, getting the thing out for a quick shoot of something can be a hassle. I'm considering purchasing some SxS cards to internally shoot 4:2:0.

 

Does chroma subsampling affect anything more than image flexibility in post? If I go down to 4:2:0 will the current dynamic range I have been shooting with take a hit? What else can that number affect?

 

Thanks for reading.

 

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#2 Tyler Purcell

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Posted 16 February 2016 - 05:50 PM

Ohh it's absolutely noticeable. In fact, 4:2:2 vs 4:4:4 is noticeable as well.

You'll see it on the transition between solid colors. So if there is something red in your shot that mates up against any other color, there will be jagged (aliasing) lines. In 4:2:2 you still see that problem, but not quite as heavily. The other big differences are of course the internal recording is 8 bit and HEAVILY compressed. The long gop internal recording smears the blacks and highlights. It has limited dynamic range even in S-log recording mode.

Remember, high definition broadcast television is 8 bit 4:2:0. So if you're OK with what that looks like, then you'll be fine.
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#3 Robin R Probyn

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Posted 16 February 2016 - 08:37 PM

Personally I wouldn't worry too much.. there has been alot of great footage out of F3,s internal recording.. Tyler has a very keen eye for detail and is a hard task master. ! . but as he rightly says.. if you are thinking to shoot log,or do alot of post tweaking it will be limiting for sure..  8 bit 422 Slog on the F5/55 is not recommended either.. I would argue that 422 to 444 isnt going to make a huge difference 99% of the time and actually Bayer sensor camera,s cant do real 444 anyway.. only stripe or 3 CCD.. but 420 to 422 is a bigger difference .. 


Edited by Robin R Probyn, 16 February 2016 - 08:38 PM.

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#4 Tyler Purcell

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Posted 16 February 2016 - 11:21 PM

I guess my point is... why own/use a camera that uses a recording format which is substandard to the imager's quality? It's one thing to have options... it's another to have zero options and be stuck with a decent imager and no way to get that signal to a recording device. It's more of a principal then anything else.

With extremely powerful coloring tools today, everyone wants to re-touch their work in post. Limiting that ability in the long run is extremely frustrating and delivers substandard images compared to a camera that does shoot better recording formats, but maybe doesn't have as good of an imager.
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#5 Robin R Probyn

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Posted 16 February 2016 - 11:58 PM

Yes totally agree sir.. thats why the OP records to external device.. which is often a pain as he has found .. so for the quick shots he wants without the hassle of the ext.. I believe the internal recording.. although not great is good enough for 90% of shots..for HD.. and you can see really nice footage shot on F3 internal.. 

 

The sensor is very good IMHO.. its always been a shame on the F3. that 1 no proper EVF.. 2 no internal 50 mbps 422 recording.. thats how the C300 got such a foothold ..

 

Maybe the OP will trade up to a second hand F5 someday .. 


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#6 Tyler Purcell

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Posted 17 February 2016 - 03:05 AM

But still... the external output doesn't offer full dynamic range RAW recording. So sure, it's a step above the horrible internal recording, but not much. 50Mbps 8 bit 422 MPEG 2 long gop recording is still SUBSTANDARD in today's world of sub $10k cameras which record 12 and 14 bit RAW/Pro Res 4444. I'm editing a documentary shot with the C300 right now and sure the imager looks great, but the files are full of MPEG noise. So yet again, you're using an external recorder on a VERY expensive camera.
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#7 Macks Fiiod

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Posted 17 February 2016 - 06:19 AM


 

Maybe the OP will trade up to a second hand F5 someday .. 

 

Haha, yeah someday. What are some sub $5k cameras (used market value) that internally record to at least 422 out the box?


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#8 Robin R Probyn

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Posted 17 February 2016 - 06:32 AM

But still... the external output doesn't offer full dynamic range RAW recording. So sure, it's a step above the horrible internal recording, but not much. 50Mbps 8 bit 422 MPEG 2 long gop recording is still SUBSTANDARD in today's world of sub $10k cameras which record 12 and 14 bit RAW/Pro Res 4444. I'm editing a documentary shot with the C300 right now and sure the imager looks great, but the files are full of MPEG noise. So yet again, you're using an external recorder on a VERY expensive camera.

 

I think the F3 is 10 bit 422 SDI out to ext recorder.. could be wrong..   yes agree C300 Log is not a real log curve ,because of  8 bit.. its pretty much Hyper Gamma 7/8 on a Sony..  XAVC Intra SLOG 2/3 from the F5/55 is alot better and linear above grey.. 

 

F3 is a very cheap camera these days though.. a few thousand dollars or cheaper.. Fs7 pushed the price down alot..


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#9 Jimmy Jib

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Posted 17 February 2016 - 11:32 AM

With the PIX 240i you can get 10 bit ProRes 444 1080p out of the F3... though most people agree the 10 bit 422 from this camera is competitive enough against the more expensive cameras. In 1080 at least.


Edited by Jimmy Jib, 17 February 2016 - 11:33 AM.

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#10 Tyler Purcell

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Posted 17 February 2016 - 01:05 PM

I think the F3 is 10 bit 422 SDI out to ext recorder.. could be wrong..   yes agree C300 Log is not a real log curve ,because of  8 bit.. its pretty much Hyper Gamma 7/8 on a Sony..  XAVC Intra SLOG 2/3 from the F5/55 is alot better and linear above grey..


That's the tricky part. Sony has many versions of the camera. The F3K and F3L are the one's which can spit out 10 bit 422 and 444. If you have a standard original model, it's an 8 bit camcorder.
 

F3 is a very cheap camera these days though.. a few thousand dollars or cheaper.. Fs7 pushed the price down alot..


Well, the FS7 has nothing to do with the F3. They are made for different purposes entirely. When I look at the F3... I see a 1080p camera that really doesn't have any special features like the FS7. It's pretty outdated today, yet Sony still believes that imager size is the reason people buy cameras. The price drop is simply because nobody wants to shoot in 1080p anymore. There are FAR better options today as well, my pocket camera being one of them for 1/4th the price.
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#11 Tyler Purcell

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Posted 17 February 2016 - 01:12 PM

Haha, yeah someday. What are some sub $5k cameras (used market value) that internally record to at least 422 out the box?


Blackmagic 2.5k Cinema camera ($2000 used)
Blackmagic 4k Cinema camera ($2500 used)
Blackmagic Pocket cinema camera ($850 used)
AJA Cion (prores only and new only)

Less then 10k
Blackmagic URSA and URSA mini 4k/4.6k
Red Raven
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#12 Landon D. Parks

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Posted 26 February 2016 - 04:07 PM

I'd say with today's modern camera technologies the difference between 4:2:0, 4:2:2 and maybe even 4:4:4 are pretty minor, and not something most people will be able to spot, unless they know what they are looking for. I know when I'm editing my GH4 4:2:0, even some of the green screen I key just works perfectly.

However, the best way I found to achieve better color depth is to shot 4k and downrez to 2k. In the case of the GH4, you can either shot C4K or UHD, and then downrez that appropriately to either 2k or 1080p (C4K - 2K, UHD - 1080p), and you'll end up with 4:4:4. Sure, its still 8-bit, though there is some debate as to rather shrinking the frame also increases the bit value a little, and on one forum I read (and can't find it again now) that when you downrez 4k 4:2:0 you actually end up with something akin to 9-ish bit, 4:4:4 footage.

Of course, this means you'll need a 4k camera that can downrez evenly at 4x.... For example, downrezing a C4K image to 1080p will not work correctly (I've tried), nor will trying to make a UHD image 2K work. It has to be a pixel-for-pixel downrez. Now, since I don't do anything in 4K, I use this method (and will for a while) to achieve better color sub-sampling, though in practice, in non-chroma key shots, I have seen little benefit other than a little sharper 1080p image (which isn't always a good thing).

In order to use this workflow, keep in mind you cannot just 'shrink' the file down... You need to go through a proper encoding process in post with the files. I use Davinci Resolve, make sure the project is set at 10-bit or higher colors, then import my C4k/UHD footage, then export it as either DNxHD/HR, Cineform, or ProRes (if your on a mac, which I'm not), making sure to select an output codec capable of holding the 10-bit 4:4:4 data.

However, the F3 is not a UHD/C4k Camera, so this workflow would not really apply in this case.


Edited by Landon D. Parks, 26 February 2016 - 04:10 PM.

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#13 David Mullen ASC

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Posted 26 February 2016 - 05:36 PM

With 4:2:2 and worse, you are basically talking about more compressed, softer, red & blue information relative to green, so I imagine a scene lit under a lot of red or deep blue lighting might look softer compared to if it had been recorded to 4:4:4.  And of course, those two channels will be harder to manipulate in timing later without picking up some artifacts.


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#14 Tyler Purcell

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Posted 26 February 2016 - 07:14 PM

However, the best way I found to achieve better color depth is to shot 4k and downrez to 2k. In the case of the GH4, you can either shot C4K or UHD, and then downrez that appropriately to either 2k or 1080p (C4K - 2K, UHD - 1080p), and you'll end up with 4:4:4. Sure, its still 8-bit, though there is some debate as to rather shrinking the frame also increases the bit value a little, and on one forum I read (and can't find it again now) that when you downrez 4k 4:2:0 you actually end up with something akin to 9-ish bit, 4:4:4 footage.


The reason why downres works better is because there are more pixels being used. It's still 4:2:0, but since there are more pixels being used, they are denser and those barriers between colors are less visible. You're still lacking TUNS of color information and the 8 bit recording makes it even harder to work with in post production. Plus, when you downres, you are actually compressing pixels, which means even more loss of information. I mean you're still dealing with MPEG recording as well, so it's really not much better.

External recording in 4k in 10 bit 4:2:2, is the best solution with that camera.

The moment you start coloring in 444 RGB 12 bit color space, is the moment you realize how BAD these little cameras really are.
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#15 Landon D. Parks

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Posted 26 February 2016 - 09:11 PM

My biggest complaint (at least with current technology) is that there does not yet appear to be a way to record 10-bit 4:2:2 Cinema 4k, at least not to any of the recorders I have found. The Atomo's Shogun can record UHD, but that is still lacking, since one of the main reasons the GH4 works so well for me is because of the Cinema 4k option, which can be downrezed perfectly to a 2k DCP file without the need for adjusting the image in post.
 

So, until the Shogun can record in a dcp-complaint frame size, I'll have to stick with my internal recording, and downrez in post.

One thing I recently noticed though when I watched 'The Witch' yesterday... It was painfully obvious to me they shot the footage at 1080p on the Alexa, and then just added black bars to the side (rather than to resize) to fit into the 2k projection... Most people probably didn't notice it, but my eye kept wondering to the edges of the frame to oogle at the half-black, half-grey pillar boxes... Which on a 50 foot screen are annoying large... Yuk!


Edited by Landon D. Parks, 26 February 2016 - 09:12 PM.

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#16 Robin R Probyn

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Posted 26 February 2016 - 09:33 PM

You can record 10bit  422 cinema 17-9 (is that what you mean) 4K or 2K with Sony F5 (with 4K upgrade) or the F55..   Fs7 too I think..


Edited by Robin R Probyn, 26 February 2016 - 09:37 PM.

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