Jump to content
Hannes Famira

Recording externally from Sony CineAlta camera

Recommended Posts

Hey everybody,

I heard somewhere in the Youtube universe that when recording externally with Sony cameras there is an undocumented difference in quality (maybe it was the bit depth?) wether you hit record on the camera itself or only on the recorder.

Can you confirm this and is this only true for mirrorless and DSLR or also for CineAlta cameras? Would it make a difference if I went via BNC or HDMI cable? Would it make a difference if I triggered record via LANC? I am a newbie with a Sony PMW-F3, recording to an Atomos Ninja Assassin and I am not sure how I would go about testing the above assertion myself.

Thanks so much and have a very happy new year!

Hannes

Share this post


Link to post
Share on other sites

AFAIK the A series are all 8 bit only.. the only benefit of ext Rec is a better color sampling fro 4-2-0 to 4-2-2.. and recording to a different codec if you want .. HDMI is a notoriously useless connection though..

 

The F3 others know more about but I think yes you can get a higher quality recording from the SDI out.. 50 Mbps rather than 35 ?.. 10 bit rather than 8..?..the achilles heal of that camera .. it can't record internally 50 Mbps.. which became the standard for broadcast HD.. . which allowed the C300 MkI to take over the market for years.. another very odd Sony decision..

 

The F5/55... Venice..you can attach a Raw recorder made by Sony ..to get 16 bit files.. there is no other reason for rec ext unless for backup and codec.. as far as I can see.. XAVC is 10 bit 4-2-2. internal.. the f55 you can record 4K and HD Mpeg proxies on the same SxS card if you want.. and the F5 with the 4K rec option installed..

Share this post


Link to post
Share on other sites

The SDI output is uncompressed (and thus at a data rate of up to 1485Mbps, depending on the frame rate and resolution involved.) Attaching a recorder such as those made by Convergent Design or Atomos will give you a recording that's (optionally) compressed down a bit from that huge figure, but still much better than the F3's rather anemic 35-megabit internal options. ProRes 4444 XQ targets 500Mbps, for instance.

 

I'm not personally sure about the HDMI output on the F3, but many sources state that it is 8-bit. HDMI is really intended for monitoring and is very commonly 8-bit, though still uncompressed and a better recording than the F3's internal option.

 

If you can get an SDI recorder, do so, as it will allow you to record 10-bit images. Given external recording the F3 is a very competent camera and a common budget option as they go for a song these days.

 

P

Share this post


Link to post
Share on other sites

 

I heard somewhere in the Youtube universe that when recording externally with Sony cameras there is an undocumented difference in quality (maybe it was the bit depth?) wether you hit record on the camera itself or only on the recorder.

 

Hi Hannes,

 

I've never heard of different record triggering methods affecting the bit depth, that would be a very odd thing to happen. The HDMI port on the F3 will only output 8-bit 4:2:2 though. So don't use that.

 

Use the SDI A port (or A and B if you need dual-link recording - i.e. for 50p or 60p output if you don't have the RGB444 upgrade for the camera).

 

I use an Odyssey 7Q with my F3, and record primarily in 10-bit ProRes4444XQ, which provides fantastic images. The F3 may be lacking in features, and ergonomically awkward compared to more modern cameras. But if you treat it as a sensor in a box, and leave the recording to a more advanced external unit - it puts out terrific image quality in SLOG.

  • Upvote 1

Share this post


Link to post
Share on other sites

The F3 is a very strange camera, it only outputs 59.94i on the SDI stream. It does not do progressive scan, just progressive segment framing, which can be decoded by several external recorders and turned into an interlace-free image.

 

Yes, the SDI is 10 bit 4:2:2, but the camera itself is only an 8 bit system. This is how and why the 444 update works, because it's 8 bit 444 rather then 10 bit 444, which is a lot more money and at the time, not available on the lower-end Sony cameras as it would directly compete against their other product line.

Share this post


Link to post
Share on other sites

I've run into an issue of poor external recording quality when doing high-speed frame rates on the Sony FS7 with the Odyssey 7Q. This was back in 2015 for a short I did that used a lot of slow motion. We were recording internally and externally at the same time. The external footage was 2k ProRes and the internal was 2k XAVC for proxy editing. However, slow-motion, externally recorded footage had heavy banding and was largely unusable. The internal proxy, however, was in tip top shape!

 

My theory for why I experienced this problem is compression. Because of the high-speed frame rate (240 if I remember), an incredible amount of data was being pumped through a BNC cable and processed by the camera's extension unit and main motherboard. I believe the banding happened either because the firmware in either the Odyssey or FS7 couldn't handle the data and was compressing the information. (I'm not sure if this issue has been fixed since)

 

A camera can output 10bit, 4:2:2 images, but it may be unwise to assume that a camera manufacturer's statement about an uncompressed 10bit 4:2:2 signal is 100% accurate, given my above situation. Testing the externally recorded image is an obvious choice, but how does one truly test if an image is 10bit, 4:2:2 uncompressed? I'm open to everyone's thoughts!

Share this post


Link to post
Share on other sites

Does the recorder have a setting for PsF.. that's what Sony cam,s give out over SDI.. its not actually interlaced ..its just splitting a progressive frame so that interlaced monitors etc could read the image.. might be your recorder thinks its getting an interlaced image ..?

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.



  • Media Blackout - Custom Cables and AKS



    Gamma Ray Digital Inc



    Serious Gear



    Wooden Camera



    FJS International



    CineLab



    Rig Wheels Passport



    Metropolis Post



    Glidecam



    New Pro Video - New and Used Equipment



    Broadcast Solutions Inc



    G-Force Grips



    Abel Cine



    Visual Products



    Ritter Battery



    Just Cinema Gear



    Tai Audio



    Paralinx LLC


×
×
  • Create New...