FS7: REC709 LUT Recorded When It Should Not Have

basspig

basspig

Veteran
I shot some footage outdoors today and have the monitor LUT set up to reflect as such on the waveform monitor.

Mon LUT is ON
SDI & Internal is OFF
HDMI OFF
SDI2 ON

The footage came out very contrasty and highlights about 5 stops overexposed and crushed blacks. Not the dynamic range I'm used to from the FS7.

I verified that the camera is in CINE EI mode and S-Log3.

Possible bug if MLUT is getting recorded to XQD card under these conditions?

This is on my second, new FS7, which was updated to FW 4.0.
 
Donny 123 said:
Is it like that when you replay from the camera too..?
Click to expand...


Yes, except for the first clip. I shot six clips. Didn't change settings between shots. Just start/stop recording. First shot has low contrast, looks like S-Log3 with no LUT. Remaining clips look like a very contrasty REC709. Actually looks more remenicent of NTSC video from the 80s.

No part of the waveform was touching the 100 IRE line, and the viewfinder image looked underexposed!

no LUT:
no LUT.jpg
with LUT:
with LUT.jpg

Even more perplexing, I repeated testing in studio, with the waveform monitor pre and then post LUT, and both shots had no LUT burned into them and look identical.

I'm thinking the unexpected behavior may have had something to do with the weather outside today. It was in the 90s and almost 100% humidity. Perhaps the camera malfunctioned due to the humidity? But I was only out there for less than ten minutes.
 
Try with SxS card and see if its the same ? otherwise looks like camera needs to go into the shop.. Humidity shouldn't have this effect ..
 
Are these from Catalyst Browse. Is there the old correction from the last time you used it on them?

If not I am baffled at the amount of issues you seem to have that nobody else ever experiences!
 
CB, as mine is set up by default.. will apply a 709 LUT to the clip you select from the thumbnails ..(maybe because I have MLUT 709 in the metadata) for LOG footage.. your first NO LUT clip is not log footage without a LUT.. for sure .. I think you have the camera set up wrong somewhere down the line..
 
This camera won't take SxS cards. The images were loaded from the XQD cards that were recorded internally.

I'm trying to think of which button could have accidentally been pressed while I was outside recording. The only one I could think of is Full Auto, which is disabled in CINE EI mode.

My other FS7 never did anything like this.

I'm pretty certain I have them both set up the same because I saved an All File from FS7 #1 and loaded it into FS7 #2.

I can't reproduce the problem in-studio.

The peculiar part is that the EVF image looked grossly underexposed.

There is one possibility I forgot about: camera malfunctions in an RF zone. Eight years ago, I had my first Sony EX1 die on me when I stepped outside the Faraday shielded studio and into the parking lot. I've had digital cameras 'freeze' on me while using them outside. Most of the time, the FS7 seemed to work okay outdoors, so I assumed this model wasn't as susceptible to RFI. Maybe the problem is the 50,000 FM/AM transmitter site 900' down the road. It's also loaded with cellular sites. I remember when I had my analog Newvicon video cameras, that using them outdoors resulted in rock music getting into the soundtrack and magenta herringbone patterns getting into the video portion of the signal.

Given that the first clip was normal and the 5 subsequent clips were as I posted above, I can suspect that an error occurred in the camera's 'brain' as I walked around probably passing through a spot where the interference was strong enough to cause an error, which caused the color/dynamic range to go awry like this.
 
basspig said:
Yes, except for the first clip. I shot six clips. Didn't change settings between shots. Just start/stop recording. First shot has low contrast, looks like S-Log3 with no LUT. Remaining clips look like a very contrasty REC709. Actually looks more remenicent of NTSC video from the 80s.

No part of the waveform was touching the 100 IRE line, and the viewfinder image looked underexposed!

no LUT:
View attachment 115953
with LUT:
View attachment 115954

Even more perplexing, I repeated testing in studio, with the waveform monitor pre and then post LUT, and both shots had no LUT burned into them and look identical.

I'm thinking the unexpected behavior may have had something to do with the weather outside today. It was in the 90s and almost 100% humidity. Perhaps the camera malfunctioned due to the humidity? But I was only out there for less than ten minutes.
Click to expand...

What are those screen grabs showing? You mention that "firts shot has low contrast" but you also say "except for the first clip". Are screen grabs showing the very first clip you shot or is it one of the clips with issue? What is the LUT that was applied ( in the second screen grab) and which software was used ?

Lastly, you say that:

Mon LUT is On
SDI & Internal is OFF
HDMI is OFF
SDI 2 is ON

What are the settings that allow SDI 2 LUT to be ON but HDMI LUT to be OFF?
 
The screen grabs are ahowing one of the affected clips. The top one is as shot. The bottom one has a REC709 technical LUT applied.

Yes, HDMI is set to recorder. This is 23.98P and center crop mode.

As to how an error in the microprocessor instructions can cause this type of error, it cannot be ruled out. A random error can manifest in many ways, some subtle, some obvious. It depends on what part of code in memory got zapped.
 
I was curious if the camera would do it again, so I went out and took some shots in the same general area.

Left is with a LUT applied in post, right image is as it came from the camera:

302_0026.00_00_45_21withLUT.jpg302_0026.00_00_45_21noLUT.jpg

One thing I can conclude: this is what I normally would expect.

Granted, the temperature today is only 81°F and humidity is down considerably. Yesterday, it was so humid that the expression "cut it with a knife" comes to mind.

Also interesting is the file sizes are about 1/4 or the ones I uploaded yesterday, despite the same frame size and same compression settings, which suggests much less noise in the picture.

I'm filing the event under the "Unexplained Mystery" category. I don't know what went wrong yesterday, but it had to be a glitch of some sort.
 
The bottom clip is def log footage.. humidity or RF wouldn't cause the original problem.. AFAIK.. it seems you original clips looks like its had a 709 LUT but over a 709 image.. I have just been 6 weeks in Singapore and I,am willing to bet the farm its was more humid that your location.. I often shoot in Tokyo which is RF central.. and never had your issue..
 
Interesting. Looks a lot like what my footage did. Well hopefully Sony finds the culprit in the code and fixes it.
 
I read about this issue at the FS7 FB group. Scares me too! Some suspected that it happens if you record too fast after powering the camera.
 
You must log in or register to reply here.
Back
Top