PXW-FS5 Native ISO’s

workshops-275 PXW-FS5 Native ISO's

This is as much for my benefit as yours as I can never remember what the native ISO (0dB) is for each of the gamma curves in the FS5.

Standard 1000 ISO
Still 800 ISO
Cinegamma 1  800 ISO
Cinegamma 2  640 ISO
Cinegamma 3  1000 ISO
Cinegamma 4  1000 ISO
ITU709 1000 ISO
ITU709(800) 3200 ISO
S-Log2 3200 ISO
S-Log3 3200 ISO

Using dB and setting it to 0dB really is so much easier with this camera!

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6 thoughts on “PXW-FS5 Native ISO’s”

  1. Does native iso remain the same at 1080 through to 4K?
    I guess I could work this out myself if I toggle between gain and iso in diplay info.

  2. Hi Alister, can you explain what is the purpose of ITU709 800%? Is this meant to be used as a normal shooting mode as an alternative to normal ITU709? If I’m submitting footage directly to a network would it be a good or bad idea to use this gamma? (Ignoring that it might go over 100% level). I can’t find anywhere an explanation of what this gamma is meant for so if you can help explain that would be much appreciated cheers

    1. 709(800) was designed for use in LUT’s as a way to monitor a large part of the 14 stop S-Log range. Below 80% it’s pretty much vanilla Rec-709, above 80% an additonal 5 stops are squeezed into a large highlight roll-off. This results in flat highlights, but a decent amount of headroom. It’s up to you whether you use it or not. If you like the way it looks, go for it.

      Rec-709 is a Recommendation (that’s what the “Rec” stands for). If you use pure Rec-709 you should get a 1:1 contrast match between capture and display, but only within the 6 stop display range that a 709 TV can show. If you shoot with a different gamma all that happens is you create a gamma miss-match, so the contrast will change. It won’t produce “illegal” video as such, just a different look, which is no different to what happens when you grade footage. So use whichever gamma curve that gives you the kind of look and range that you want, bearing in mind that the greater the capture range the lower the on-screen contrast.

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