S-Log Exposure Discussion

[Justin Molush]

For you guys that have shot with this cam before, would I be correct in saying that I would be getting the full DR of the camera while capturing to .DPX with my decklink quad? It doesn't sound like that much of a clipping issue going from 104-109 IRE, but when shooting in harsh contrasty additions, Ill deal with the extra size of DPX for that extra bit of latitude in post.

[Alister Chapman]

104 to 109 clipping isn't much but it is almost 5% of the total range, which if we assume to be 12 to 13 stops is over half a stop.

DPX should be OK. Most recorders and codec will allow at least 108%. The 104 clip is a ProRes specific issue as according to Apple they want to ensure that users of ProRes stay within the limits normally specified for broadcast TV, which is a nominal 100% maximum with overshoots to 104 allowed.

[Duke Marsh]

Although I haven't seen it yet AJA said they were going to give a free firmware upgrade that included the ability to record to DNxHD. I'm looking forward to getting that extra bit of DR back.

[Alister Chapman]

OK, I wrote about the clipping issue without digging deep enough. If you read the original post about clipping I claimed that ProRes was clipping my files at 104%. Well it's NOT. The ProRes files are just fine, BUT some Quick Time applications are clipping the files at playback. In FCP the files are OK. Premiere appears to be reducing the level of the files a little and Quick Time player is clipping the files at approx 104. So this isn't as big an issue as I thought, but you do need to keep an eye out as to what is happening with highlights and super whites depending on what software you are using. I was wondering why I hadn't seen this before. In part it because I am no longer using FCP.

[Nate Weaver]

Originally Posted by Alister Chapman

OK, I wrote about the clipping issue without digging deep enough. If you read the original post about clipping I claimed that ProRes was clipping my files at 104%. Well it's NOT. The ProRes files are just fine, BUT some Quick Time applications are clipping the files at playback.

This is the same phenomenon as Canon Quicktime files clipping, etc etc. Quicktime re-wrapped XDCAM native files do it too.

In the header of each Quicktime file is a set of metadata that instructs the decoder how to render the file, if the decoding program chooses to heed it. Display resolution, contrast, saturation level, etc etc.

Anyway, with that info, you can see how all sorts of wacky things that can happen from program to program.

In any case, i've found that any highlights "clipped" in this manner are recoverable in almost any color correction program, and most NLEs. When working in Davinci with Quicktime files, I routinely check the material for this and often I can lower the gain wheel and watch highlights come back on the scopes as I dial it down.

[Alister Chapman]

I was wondering why, as a big user of ProRes, I had not seen this before. I've stopped using FCP and am flipping between Avid and Premiere and other apps as well as using Quicktime Player a lot more and this is where I'm seeing the issue. As you say if you bring the levels down, all is the data is there.

That will teach me to not investigate properly. Should have gone back to FCP and checked sooner, but I'm trying to force myself to learn the other NLE's rather than falling back on "old faithful" all the time.

[Leonard Levy]

Don't be too hard on yourself Alister. Your attention to detail has saved hundred's of us from needing to bother at all. Thanks for all that work and willingness to share the results.

[Nate Weaver]

Originally Posted by Alister Chapman

I was wondering why, as a big user of ProRes, I had not seen this before.

It's not even a ProRes issue, per se. More of an issue with the interactions of the device/software that generated the Quicktimes, and the program reading them.

First time I saw it was with 5D files.

[Hornady Setiawan]

Thank you guys,
your findings are truly insights that even Apple, Sony, etc. didn't see, let alone me ordinary user.
Very valuable information.

Now, is there info on service menu in F3?
In F350 I can display gray ramp and see the gamma curve in waveform monitor. Can we do this in F3?

[Dennis Dillon]

Hornady,
I do not believe a Test Saw option is on the F3.
On the 800 it is in the Paint Menu

[Chris Medico]

Originally Posted by Alister Chapman

OK, I wrote about the clipping issue without digging deep enough. If you read the original post about clipping I claimed that ProRes was clipping my files at 104%. Well it's NOT. The ProRes files are just fine, BUT some Quick Time applications are clipping the files at playback. In FCP the files are OK. Premiere appears to be reducing the level of the files a little and Quick Time player is clipping the files at approx 104. So this isn't as big an issue as I thought, but you do need to keep an eye out as to what is happening with highlights and super whites depending on what software you are using. I was wondering why I hadn't seen this before. In part it because I am no longer using FCP.

Avid Liquid would do the same thing. It clipped any imported video at 100% but if you captured video via firewire (or SDI) the limit was 109%. I ran into that problem when I started capturing HDV video onto hard drive recorders and bringing it in as files. All the highlights were harsh and crunchy.

Luckily that hasn't been the case with Media Composer.

[Nate Weaver]

Originally Posted by Dennis Dillon

Hornady,
I do not believe a Test Saw option is on the F3.
On the 800 it is in the Paint Menu

There is, I've used it. It's in the service menu.

[Hornady Setiawan]

Originally Posted by Nate Weaver

There is, I've used it. It's in the service menu.

Hi Nate,
Please give us some insights how to enter service menu in F3? :)

Thanks!

[Dennis Dillon]

Originally Posted by Nate Weaver

There is, I've used it. It's in the service menu.

Nate
Thanks. Sony is a bit hesitant to provide me with the special handshake. Understandable.

[Steve Kalle]

I just checked some footage and I don't see anything different between XDCAM EX and Pro Res in Premiere Pro CS5. (recorded to a PIX240 at 0 or 6db).

XDCAM on left and Pro Res on right.