GH5 Controlling Blown Highlights with GH5?

B

bhuether

Member
Hi, the last video I did with my GH4 was home video of my cat and after doing the shots I realized how many of them had blown highlights.

Video is here:


That camera was stolen while visiting Boston and I just received a GH5 as replacement.

My first pressing question is what techniques can I use to better control highlights? I don't always know what I am going to do when shooting my cat. I can't know what the brightest expected scene is that I plan to use in post. So I am trying to find a good compromise where I can get nice dynamic range under varying conditions, realizing that the unexpected actions of the cat often require me to react in realtime with no shot planning.

It would be awesome if the camera has some setting that amounts to "When blown/clipped highlights are detected, start using automatic control to tame those highlights somewhat."

Thanks!

Brian
 
Use HLG or VLOG and do not over expose. That's all you can do, it is limited by the dynamic range of the camera.
 
I use the easy-to-reach exposure button on the GH5, which makes it really easy to adjust the exposure. Obviously, if you are concerned about blown-out highlights, reduce the exposure. I've discovered that you can adjust the exposure on the GH5 as it records, and it smoothly adjusts the exposure to the new setting. It's pretty nice, actually.

One other tip for not blowing out the highlights is to use the ISO just below where you notice possible overexposure. If you're working at ISO 800 and you get zebra lines (or whatever indication you have set up for overexposure), reduce the ISO to 400 and shoot in that. If that is too dark, raise it a bit in your editing software. Still waiting for that camera with contrast of 18 stops. :grin:
 
Thanks. One of the things I notice in watching films lately is that scenes that seem like they could be in danger of overexposure (backlit, etc) seem to have this smooth washed out look where you have this subtle yellowish glow. I rarely see pure white highlights in very bright film scenes. Has me wondering if this is some tried and true technique, something done in post.

Also has me wondering if it is time for camera industry to open their cameras up to 3rd party plugins. Would be pretty wild to have plugins that can control things like exposure beyond what cameras currently do. For instance a plugin that monitors exposure and applies exposure curves based on user defined parameters, such as "if past 3 seconds saw some highlights threshold crossed, then ramp down exposure and apply non linear curve to highlights."

Or maybe voice control :) Which manufacturer will be first to add voice control. So you are shooting something and would like to make some change on the fly and you just tell the camera what you need. Of course only useful when recorded audio is not a concern.

thanks again, Brian
 
This thread reminded me of a similar one on BMCuser a while ago...

If you check the original DNG in the first post - in which the exposure is completely blown out - and then people's results below bringing back a lot of those highlights, it will make you want a camera that shoots RAW...which is kind of what you're talking about with your "plugin" idea. Essentially you're asking for more flexibility and that's what RAW will provide you.

http://bmcuser.com/showthread.php?21005-Is-my-footage-salvageable&highlight=lightroom

P.S. If you can't see the photos.

Before.jpg

After.jpg
 
Thanks for the info. Is that to say GH5 does not shoot RAW? Is it RAW only for stills? Is v log supposed to be something close to RAW for video (as far as what it enables in post)?

thanks,
Brian
 
It's different. The GH5 does not shoot RAW video (but V-LOG does provide you more flexibility in post vs. the camera's other picture profiles).

No Japanese stills camera shoots RAW video right now although Nikon is supposedly working on it via an external recorder.
 
bhuether said:
Thanks. One of the things I notice in watching films lately is that scenes that seem like they could be in danger of overexposure (backlit, etc) seem to have this smooth washed out look where you have this subtle yellowish glow. I rarely see pure white highlights in very bright film scenes. Has me wondering if this is some tried and true technique, something done in post.

Also has me wondering if it is time for camera industry to open their cameras up to 3rd party plugins. Would be pretty wild to have plugins that can control things like exposure beyond what cameras currently do. For instance a plugin that monitors exposure and applies exposure curves based on user defined parameters, such as "if past 3 seconds saw some highlights threshold crossed, then ramp down exposure and apply non linear curve to highlights."

Or maybe voice control :) Which manufacturer will be first to add voice control. So you are shooting something and would like to make some change on the fly and you just tell the camera what you need. Of course only useful when recorded audio is not a concern.

thanks again, Brian
Click to expand...
You cannot "curve" exposure. Lookup sensor saturation.
 
I guess what I mean is having the camera adjust ISO on the fly anticipatively. So that in a 3 second period, you might see the camera sensor sensitivity changing. Or better yet, imagine there is some omnidirectional light meter that you use at several points before shooting. So now the camera already knows what the lighting conditions are like 360 degrees around you at various elevation angles, etc. Then the camera has built in inertial navigation system and the camera knows where the camera is pointing relative to some starting point of reference. So I start out shooting a dark scene, maybe under a table and unexpectedly I shoot towards a sunny window. If the camera knows where it is now pointing and knows the trajectory that it is moving along, then perhaps it would know "Ok, based on this motion in half a second the camera will be faced with extreme brightness." Or even without using navigation sort of data you could almost maybe get away with using current brightness data and detect if brightness is rapidly increasing (which could indicate quick movement) and then quickly lower ISO. Engineers would have a lot of experimenting to get this to work even horribly then over time like with any algorithm it could be refined. Just seems that as smart as cameras are that there should be some next evolution. It might even amount to using current practices in machine learning. So maybe you have new camera and the camera has collected months of data on your personal use. Such as what was happening right before those moments that you then had blown highlights (such as the speed of increase in brightness). Then if similar conditions arise the camera knows when to dial ISO back. Or I am overthinking and this just comes down to better camera operation by the user!
 
Overthinking for sure. All you need is a [preferably very] high dynamic range camera with a solid format, and the rest can be done in post. What you see in Hollywood (not that everything is good there) doesn't come straight from their cameras. There are people behind computers/screens working. Pushing and pulling.
 
The golden rule has always been expose for the highlights and either use fill light / reflector to open up the shadows. If you have no supplementary lighting, then you can try lifting the shadows in post. RAW footage is very flexible in post, LOG and flat profiles have some flexibility but don't expect miracles.
 
The new Blackmagic Design Pocket Cinema Camera 4K has a new RAW format called "Blackmagic RAW", and it also records ProRes directly. In theory, using Blackmagic's DaVinci Resolve Pro editing software (the $300 version), you can massage this RAW video in ways that a standard MP4 or MOV file won't gracefully handle. That is the promise, anyway. I like Blackmagic (and use Resolve for a few projects), but its products sometimes take a long time to work the bugs out and live up to their potential.
 
BobKo said:
The new Blackmagic Design Pocket Cinema Camera 4K has a new RAW format called "Blackmagic RAW", and it also records ProRes directly. In theory, using Blackmagic's DaVinci Resolve Pro editing software (the $300 version), you can massage this RAW video in ways that a standard MP4 or MOV file won't gracefully handle. That is the promise, anyway. I like Blackmagic (and use Resolve for a few projects), but its products sometimes take a long time to work the bugs out and live up to their potential.
Click to expand...

But it won't recover blown highlights any better than the GH5 codec.
 
What about CinemaDNG RAW...will that recover highlights better for you?

Or is it still just like the GH5? :2vrolijk_08:
 
So based on this thread, seems some tips are

- Shoot in HVG or V0LOG
- Adjust ISO on the fly as needed

What do you think of this video where it is claimed that the H265 codec is the closest that GH5 comes to RAW?
https://www.youtube.com/watch?v=znLS7h2dSXM

Also in the GH5 manual there is mention of the Like 409 photo style using knee compression in overexposed areas? Any advantage to this vs V-LOG?

Thanks again, Brian
 
bhuether said:
So based on this thread, seems some tips are

- Shoot in HVG or V0LOG
- Adjust ISO on the fly as needed
Click to expand...

My suggestion was to adjust the exposure on the fly, using the GH5's convenient exposure button. I do not know if you can control the ISO on the fly.

Bob
 
NorBro said:
What about CinemaDNG RAW...will that recover highlights better for you?

Or is it still just like the GH5? :2vrolijk_08:
Click to expand...

Once the sensor sites are saturated i.e 'clipped' there is no magic in BRAW or even cDNG that can get this back - what's so difficult for you to understand about this well understood concept of digital capture?
 
Many people use variable ND filters to control exposure so look at this. I wouldn't ISO on the fly even if it's possible as changing ISO also changes the dynamic range and the noise.
 
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