Raw and the PXW-FS5

advertise-here-275 Raw and the PXW-FS5

This isn’t a “how to” guide. There are many different recorders that can be used to record raw from the FS5 and each would need it’s own user guide. This is an overview of what raw is and how raw recording works to help those that are a bit confused, or not getting the best results.

First of all – you need to have the raw upgrade installed on the FS5 and it must be set to output raw. Then you need a suitable raw recorder. Just taking the regular SDI or HDMI output and recording it on an external recorder is not raw.

Raw is raw data direct from the cameras sensor with very little image processing. It isn’t even a color image, it won’t become color until some external processing, often called “De-Bayer” is done to convert the raw data to a color image.

For raw to work correctly the camera has to be set up just right. On the FS5 you should use Picture Profile 7. Don’t try and use any other profile, don’t try and shoot without a profile. You must use Picture Profile 7 at it’s factory default settings. In addition don’t add any gain or change the ISO from 3200. Even if the scene is a dark one, adding gain will not help and it may in fact degrade the recorded image.

White balance is set using the appropriate SGamut + color temperature preset chosen from within Picture Profile 7, there are only 3 to choose from for S-Gamut, but with a raw workflow you will normally fine tune the white balance in post. No other color matrix or white balance method should be used. Trying to white balance any other way may result in the sensor data being skewed or shifted in a way that makes it hard to deal with later on.

All of the above is done to get the best possible, full dynamic range data off the sensor and out of the camera.

If you are viewing the S-Log2 (ie don’t have viewfinder gamma assist enabled) then the exposure level that Sony recommend is to have a white card at 60%. So consider setting the zebras to 60%. Don’t worry that this may look a bit dark or appear to be a low level, but that’s the level you should start with… More about exposure later on.

This raw data is then passed down the SDI cable to the external recorder. The external recorder will then process it, turn it into a color signal (de-bayer) and add a gamma curve so that it can be viewed on the recorders screen. Exactly what it will look like on the monitor screen will depend on how the recorder is set up. IF the recorder is set to show S-Log2, then the recorders screen and the FS5’s LCD should look similar. However you might find that it looks very different to what you are seeing on the FS5’s LCD screen. This is not unexpected. If the recorder is setup to convert the raw to Rec-709 for display then the image on the recorder will be brighter and show more contrast, in fact it should look “normal”.

Under the surface however, the external raw recorder is going to be doing one of two things (normally at least). It’s either going to be recording the raw data coming from the camera as it is, in other words as raw. Or it will be converting the raw data to S-Log2 and recording it as a conventional ProRes or DNxHR video file. Either way when you bring this footage in to post production it will normally appear as a flat, low contrast S-Log2 image rather than a bright, contrasty rec-709 image. So understand that the footage will normally need to be graded or have some other changes made to it to look nice.

Recording the actual raw data will give you the best possible information that you can get from the FS5 to work with in post production. The downside is that the files will be huge and will take a fair amount of processing power to work with. Recording a ProRes or DNxHR video file with S-Log2 gamma is second best. You are throwing away a bit of image quality (going from 12 bit linear down to 10 bit log) but the files should still be far superior to the 8 bit UHD internal recordings or even an external recording done via the HDMI which is also limited to 8 bit in UHD.

Most raw recorders have the ability to add a LUT – Look Up Table – to the image viewed on the screen. The purpose of the LUT is to convert the S-Log2/raw to a conventional gamma such as Rec-709 so that the picture looks normal. If you are using a LUT then the normal way to do things is to view the normal looking picture on the recorders screen while the recorder continues to record S-Log2 or raw. This is useful as the image on the screen looks normal so it is easier to judge exposure. With a 709 LUT you would expose the picture so that the image on the recorders screen looks as bright as normal, skin tones would be the usual 70% (ish) and white would be 90%.

There is a further option and that is to “bake in the LUT”. This means that instead of just using the LUT to help with monitoring and exposure you actually record the image that you see on the recorders screen. This might be useful if you don’t have any time for grading, but… and it’s a big BUT…. you are now no longer recording S-log2 or raw. You will no longer have the post production grading flexibility that raw or S-Log2 provide and for me at least this really does defeat the whole point of recording raw.

Exposure: Raw will not help you in low light. Raw needs to be exposed brightly. If viewing S-Log2 then Sony’s recommendation is to have a white card or white piece of paper at 60%. I consider that to be the absolute minimum level you can get away with. The best results will normally be achieved if you can expose that white card or piece of paper at around 70% (when looking at an S-Log2 image). Skin tones would be around 55%. If you expose like this you may need to use a different LUT on the recorder to ensure the picture doesn’t look over exposed on the recorders monitor screen. Most of the recorders include LUT’s that have offsets for brighter exposures to allow for this. Then in post production you will also want a LUT with an exposure offset to apply to the S-Log2 recordings. You can use the search function (top right) to find my free LUT sets and download them.

SEE ALSO: https://www.sony.co.uk/pro/article/broadcast-products-FS5-raw-shooting-tips

 

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15 thoughts on “Raw and the PXW-FS5”

  1. Very VERY nice article as always! Alister can you talk a bit about this software and how it can be used with Sony?
    My setup is: FS5 + Odyssey 7Q+.

    Thanks

  2. Thanks for the write up. Question though. Why use SLOG2 instead of SLOG3 with RAW? I had read elsewhere that PP9 was the profile to use for export. I should note i’m using a shogun inferno so I can’t record raw, just the 10-bit output into prores or dnxhd.

    Thank you.

    1. PP7 is the recommend profile. The raw signal contains a metadata flag for S-Log2 no matter what the camera is set to and the recorders will default to S-Log2. In addition as there are no LUT’s in the camera S-Log2 will provide a higher contrast image that is easier to focus and judge exposure with. There is absolutely no benefit to S-Log3 when using raw and Sony’s 12 bit raw is decoded as S-Log2 by default.

  3. Hi Alister,

    Got another issue.
    http://i.imgur.com/tE6RNII.jpg

    Image on the left is what i’m getting out of the shogun. Image on the right is out of the camera. The color is way off. Recorded PP7 as you said, and the shogun is not set to record any lut into the image.

    Thank you.

    1. See my other replies. When you record ProRes you are not recording raw. The recorder has to take the raw data and convert it to a YCbCr conventional video signal and as part of that process it has to add a gamma curve and conventional color encoding, so this can and often will result in an image different to what is seen in the viewfinder. I also wonder if you are using Adobe Premiere? as this does some strange things to the signal levels of Sony’s S-Log XAVC.

      1. Hi Alister, yes I am using Premiere.
        The images have the same look in Resolve as well. The XAVC is much flatter than what i’m seeing on the files from the inferno. I really don’t care about “True RAW” I just wanted an uncompressed signal from the FS5 so I can get a similar image to the FS7’s XAVC-I. I’m shooting a feature doc with very long interview segments, I don’t have the space to handle all those DNG’s.

        I’ve noticed also that no matter what picture profile I choose, it basically looks the same on the Shogun Inferno. I can change the white balance, and there appears to be a slight shift in color if I move from PP7 to something like PP4, but no matter what the picture profile, it doesn’t seem to be changing it.

        Is there no way to get uncompressed 4K SLOG out of the camera?

        Thank you,

        1. Hi Paul.

          I’m experiencing the same thing as you. The Infernos footage is waay more contrasty than the FS5s internal.

          Have you figured out what’s going on, and any “solution”?

        2. As I tried to explain in the article when using raw you are getting raw sensor data out of the camera, so there is no gamma curve etc, so changing the profiles will make no difference, it’s the raw information from the sensor. But you MUST use PP7 to ensure the sensor gain is set correctly.

          The Inferno has to decode the raw to turn it into a viewable image, it is applying it’s own processing and adding it’s own gamma curve, so it may look different to the cameras own display.

          You can get uncompressed S-Log by going back to the conventional shooting mode and taking the conventional SDI or HDMI output to an external recorder. However this will be limited to 8 bit in UHD.

  4. I’ve sent the screencaps to Atomos, they asked for the waveform information, nothing back yet. I’m very irritated at the whole thing. I bought the FS5 and the Inferno specifically so I could get uncompressed 10-bit prores, the RAW is too much to handle for 4 hour documentary interviews.

    Sure you can go HDMI, but it’s 8 bit, so that’s a fail. If Atomos provided a LUT or something that corrected for their own gamma curve, maybe that would be okay, but they are basically just spitting out a compressed image.

    1. Lets make sure we are getting our terminology right here. I’m guessing that by compressed you mean restricted in range? Because ProRes is always compressed and that’s why the files are so much smaller than the uncompressed cDNG raw files. If the files were uncompressed YCbCr then they would actually be much larger than the raw.

  5. Hi guys,

    Alister thank you as usual for cutting through the fog of the internet to explain things so simply. I am really just wanting to get 4K 10bit pro res out of my FS5. What I’ve interpreted from the comments is that this is possible when outputing RAW from the camera to a recorder that then compresses the signal to pro res. I made th mistake of getting a Video Devices pix e5 and am thinking that it won’t be able to interpret a raw signal from the FS5. Can anyone confirm this? I do documentary so was really wanting to keep the small form factor of the camera but at this point I might just need to get an FS7!

    1. The regular HD output is 10 bit. But to get 10 bit 4K you need the raw upgrade option in the camera plus a compatible recorder such as an Atomos Flame/Inferno that can convert the raw to ProRes.

      Generally if you just want high quality 10 bit 4K the FS7 is my recommendation. But don’t dismiss the FS5’s 8 bit. It can produce wonderful results if treated carefully.

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