View Full Version : Color correcting X70 video


Paul Anderegg
March 21st, 2016, 08:22 PM
So my X70 got used by a fellow photog to shoot another photogs wedding. He's used to using large ENG cameras, so I had to train him on the little X70 controls, and he was warned repeatedly to protect the highlights, that I can lift dark video, but once you overexpose, it's ruined. Well, got the cards back, and 90% of the footage is slammed over a stop overexposed. The overexposure was so severe, the knee altered all the highlight colors severely, talking skin tones in bright red/magenta and bright yellow, on the same person, on the same shot. :-(

I've never had to grade video is such bad condition before, so I thought I would pass on what I learned about repairing the X70 highlights and colors when this happens, since it seems to be something a lot of you deal with. I messed around with Catalyst Browse, and even downloaded Divinci Resolve, but I am not too familiar with the color wheels, so I stuck with FCPX. FCPX puts the color wheels in a box, but the general highlights shadows mids gain lift etc are all pretty generally referenced.

So, first thing I learned to do is BRING DOWN HIGHLIGHT (gain?) saturation, which erases those weird color shifts you get with overexposed knee. Second, you bring up midtone (gamma?) saturation, which is below the knee compression threshhold, so it's still happy colors. You can then work to bring your levels into happy compliance. I brought my mids (gamma) down a huge amount, then reduced highlights until things like foreheads became more then once gradient, then brought up the blacks (lift?) to a happy level where I could see some shadow detail.

For correcting white balance, I found that it was 50/50 if mid or highlight alterations rendered better results, typically dependent on if it was indoor or outdoor footage. I can't stress enough how important knocking down the highlight saturation is at the very beginning of the process when dealing with anything that has been slammed against the knee circuitry in these cameras. To play with this, go ahead and shoot a tablelamp or something, and overexpose it to the point that the lighted areas go a weird orange color, then take the clip into your NLE and do the recommendation just to see how it works.

To complicate matters more, I handed off the camera in 4K 4:2:0 mode, not HD 4:2:2! Using Catalyst Browse, I converted everything to ProRes 422, which I believe takes the 4K 4:2:0 colorspace and makes it HD 4:2:2 using the extra pixels?

Paul

Cliff Totten
March 21st, 2016, 10:22 PM
I REALLY wish the X70 had SLOG-2. I'd even pay for it as an option. Hell, the Sony Alpha division gives out SLOG-2 on the A7-II series, the A6300 and even the RX point and shoots have it.

I guess the X70 costs too much to have SLOG. If Sony would have lowered the price closer to the consumer cameras than it would have been eligible to have SLOG.

SLOG-2 could have easily protected those highlights. (if they weren't "that" bad)

CT ;-)

Noa Put
March 22nd, 2016, 02:35 AM
even the RX point and shoots have it.
That's because slog is a feature for consumer camera's, like the 1200x zoom is :)

From what I understand you best don’t use a log when you are shooting a limited dynamic range scene, like a candlelit venue at a wedding plus if you use it in a scene that has a large DR, you need to understand how to expose and how to colorcorrect, I"m sure Paul knows how to deal with the last part but that's of no use if his cameraman doesn't know how to expose.

I've said it before, if I had to hand over a camera to a person that has no experience using it (even if they are experienced shouldercamera operators) and if they have no experience shooting weddings I would just leave a picture profile at standard and set the zebra's in a way where anything that has stripes is gone so the operator knows that whatever has stripes on it has no detail. If they then still overexpose important parts, well, there is no cure for stupid.

I have hired a experienced cameraoperator who mainly did corporate film in the past with no wedding experience to take over a wedding from me, he was overly confident when I tried to brief him and had an attitude like "yeah, yeah, I know, move on pls" :) but nothing could prepare him for the unforgiving fast paced environment like a wedding and he scr*wed up big time leaving me with the task of telling the client why several shots looked like crap, I was so stupid of wanting to edit it myself, just like Paul did and I am sure Paul had the same feeling as I when I was browsing though the footage.

Wacharapong Chiowanich
March 22nd, 2016, 02:59 AM
The 4K, both 60Mbps and 100Mbps, from my AX100 always has trouble coping with even moderately contrasty scenes. At the higher brightness levels above the knee or if not the knee perhaps from some mid level EV highlights blow out very quickly and abruptly. Exposing for highlights hardly helps since once I rein in the clippings to an acceptable level, the image gets too dark and this means heavy lifting of both the shadows and mid-level gamma in post, creating plenty of noise.

There is not even a simple contrast, saturation and sharpness control on the AX100 that would certainly help like what a number of my much cheaper Cybershot still cameras have. When having to shoot in high contrast environments, it's either some help from supplementary lighting or light filtering/balancing sets or I'm out of luck.

I have no idea how the 4K from the X70 would fare compared to that from my AX100 but it should be at least similar or very close since as far as I know the range and depth of tweaking of the image parameters are available only to the 10-bit 4:2:2 1080p recording.

Noa Put
March 22nd, 2016, 05:24 AM
I've never had to grade video is such bad condition before, so I thought I would pass on what I learned about repairing the X70 highlights and colors when this happens, since it seems to be something a lot of you deal with.

Well, actually "we" don't have to deal with that as we know how to expose our shots taking the limitations of our camera's into consideration, If you have to deal with video that is badly overexposed a lot then it's time to find another hobby. :)

Bad overexposed shots will continue to look like crap, no matter what you do with it, underexposed shots however has more recovery possibilities.

It's pretty simple, as long as you get the basics right (correct exposure, whitebalance, focus etc) you can keep the grading part in post to a absolute minimum which is something that will save you hours of time and when you are in the weddingbusiness that can be crucial if you are swamped with work.

Craig Seeman
March 22nd, 2016, 09:09 AM
I'd love to see before/after frames just to see what you were up against.

Personally I have a hard to understanding how an experienced camera person, even with new camera, doesn't understand zebras. Even in some pretty difficult cases where protecting the highlights means introducing noise in post when you stretch the blacks out, there's Neat Video which, while a slow render, can help with that. As everyone knows, lost detail is gone forever.

I'd really like to understand what he didn't see or know. Zebra and maybe a proper picture profile should keep you decent. What mistake would a real experienced camera person make?

Noa Put
March 22nd, 2016, 09:53 AM
I know that Paul has a custommade profile for shooting at night for his news coverage if I understood this right, it might be that under normal conditions, like shooting in daylight the same profile might require a different interpretation of the zebra's or histogram? That's why I always say to use a factory standard profile if you are not sure because that always will work.

Jim Stamos
March 22nd, 2016, 04:22 PM
Was this guy shooting manual,surprised there would b issues unless he wasn't adjusting the iris and gain as needed,plus of course manual wb.
If he was all in auto, he's no so experienced

Paul Anderegg
March 30th, 2016, 07:47 PM
Well....it was extremely bright sunlight, and I may have forgotten to put the eyecup on it for him. :-(

I set him a Zebra 95% button, but had it set to off as I was thinking this would be indoor, but he was told which button activated Zebra.

I didn't realize how hard this camera is to shoot in daylight, until i had to shoot a helicopter rescue on the mountain next to my house. Even with zebras, I could not tell exposure using either EVF or LCD, it was horrible. I completely understand how he couldn't get it right, when even me on my own camera was blowing out and underexposing day video.

And I can't post any clips because the people involved are TV personalities, so they don't like being seen by random people out there. :-)

Paul

Dave Blackhurst
April 1st, 2016, 04:02 PM
Get the skintones right, call the rest "artistic interpretation"....