Ensuring correct exposure - please help

[KDog]

Hi All - apologies if this has been covered in the past (I did do a search but it mostly came up with long exposure discussions).

Anyhow, I'm interested to hear how you all ensure that your exposure settings are correct when shooting. I shoot in D-Log so that I get the most out of my footage in post, and I shoot with over-exposure (zebra) alert activated. I always set my camera settings for the light etc. before each new shot, however it seems that my iPhone screen is misleading me - I visually set exposure settings to what appears to be in the sweet spot, however routinely when I get back into post and apply the D-Log to Rec.709 LUT it really crushes the shadows and I get very dark parts of the footage. I can normally fix it with exposure adjustments in post, but obviously it's always better to film correctly exposed.

Today I went out in bright sunlight and shot using settings that looked on the phone screen like it was hugely over-exposed and murdering the highlights, but then when applying the Rec.709 LUT everything fell into place perfectly. I didn't get any over-exposure zebra pattern on my phone screen, but it did look blown when filming. I've attached a capture of the Log next to the Rec.709 LUT with no other effects applied and the Log doesn't look over exposed here, but on the phone screen while shooting, it really did.

What's the best way to ensure that you're on the money with exposure settings? Do you dial all the way up to over exposure and then wind it back a stop or two? What are your experiences with this?

Thanks.

P.S. I'm using the free GroundControl D-Log to Rec.709 2017 LUT which comes up great when exposed correctly.
P.P.S. I always apply between a 2 and 4 stage colour grade workflow in post (not just LUT set and forget), but that's a different thread I'd imagine.

 

[cobra46]

I'm no expert but I use the histogram and if I error to one side or the other I try to error on the too dark side.

 

[KDog]

Thanks, that would make sense; haven't used the histogram in the past because it made the screen very cluttered, but that would be the logical solutions.

Thanks.

 

[Xcel]

If you want a clear camera view, you can swipe up while flying and it while hide the entire HUD and only display the camera view and battery % on your phone. Swipe again and the HUD comes back.

 

[ecoleman]

Firstly I'd stop using D-Log and secondly you should be using your histogram to check exposure, never rely on your screen.

 

[KDog]

Firstly I'd stop using D-Log and secondly you should be using your histogram to check exposure, never rely on your screen.

Got it on the histogram, but what's wrong with D-Log? I appreciate your opinion, but if you won't qualify your response it doesn't really help me. My understanding of D-Log is that it captures the widest dynamic range, preserves the most detail in highlights and shadows and is best for post manipulation into a gamma colourspace. If not D-Log, what should I be shooting in and why? What advantage is there to be gained by limiting the dynamic range during filming?

 

[Ziggy01]

Got it on the histogram, but what's wrong with D-Log? I appreciate your opinion, but if you won't qualify your response it doesn't really help me. My understanding of D-Log is that it captures the widest dynamic range, preserves the most detail in highlights and shadows and is best for post manipulation into a gamma colourspace. If not D-Log, what should I be shooting in and why? What advantage is there to be gained by limiting the dynamic range during filming?

The D-Log for the Mavic is not worth a dime. The sensor is far too small and the bit-rate too low to produce anything that resembles a decent Log V. Setting to None or Cine will produce far superior results.

 

[KDog]

The D-Log for the Mavic is not worth a dime. The sensor is far too small and the bit-rate too low to produce anything that resembles a decent Log V. Setting to None or Cine will produce far superior results.

Thanks - I'll give it a test and check it out. Will try to take some comparative test shots and post them here.

 

[Hurseyc]

The D-Log for the Mavic is not worth a dime. The sensor is far too small and the bit-rate too low to produce anything that resembles a decent Log V. Setting to None or Cine will produce far superior results.

I thought they had "fixed" D-Log in a recent firmware release. Is that not the case?

 

[ecoleman]

Got it on the histogram, but what's wrong with D-Log? I appreciate your opinion, but if you won't qualify your response it doesn't really help me. My understanding of D-Log is that it captures the widest dynamic range, preserves the most detail in highlights and shadows and is best for post manipulation into a gamma colourspace. If not D-Log, what should I be shooting in and why? What advantage is there to be gained by limiting the dynamic range during filming?

You just need to look around this forum to see what's wrong with D-Log. D-Log isn't preserving anything, it's just crushing your DR into an unesable mush.

 

[KDog]

I thought they had "fixed" D-Log in a recent firmware release. Is that not the case?

The more I read into this, the more it seems it's a hardware limitation rather than a firmware issue. To be honest I don't understand the technical drivers, but it's been stated a number of times that bitrate compression of 60mbit/s for 4K is the primary driver. Evidently the compression isn't reduced for lower resolutions (so there's no option for say, 60mbit/s at 1080), which on face value seems like it could be a firmware fix, but I don't understand the mechanics of the MP sensor enough to know if this is correct.

I've even read on other forums that this high compression is an issue on the zenmuse cameras as well, although unsure how old that was.

 

[KDog]

You just need to look around this forum to see what's wrong with D-Log. D-Log isn't preserving anything, it's just crushing your DR into an unesable mush.

Like everything on the internet, there's a pretty good diversity of opinions in here both ways around shooting in D-Log, so it's difficult to find a single source of truth, hence the specific question. That's why it always helps to qualify our responses instead of just assuming that people will accept our opinions on face value.

As per my initial post, I've produced both excellent and very poor results shooting in D-Log (in both good and low light both ways), hence initially diagnosing the variable as being exposure settings rather than colour space.

My now current understanding is that it's better to shoot as close to final look as possible, since the compression brings out artifacts more and more with each layer of processing in post. Obviously this limits how much flexibility one has in creating the final look in post, so isn't ideal, but I guess that's the trade-off for portability and a consumer price point.

I still think there may be some secrets to achieving good results in D-Log hidden in how the colour space is mapped to Rec.709. The main complaint about D-log seems to be crushing shadows, not about blowing out highlights, and my experience shows me that the LUT shifts the whole luma profile down quite considerably. If someone was able to actually provide some insight into this, it might be more helpful than just slagging off D-log and image compression.

 

[ed1nh0]

I am very interested in this subject. According to DJI, the D-Log was "fixed" since fw .0400.
We all know the Mavic cam is far from a DSLR, but it leaves nothing to be desired for a decent drone camera. And we don't need to compare it to the Inspire's X5S.
Aside its limitations and settings, I see nothing wrong with D-Log. Well I never tried any other profile for filmmaking purposes.
Looking forward to see what others could add as relevant info.

 

[newnan3]

If you want a clear camera view, you can swipe up while flying and it while hide the entire HUD and only display the camera view and battery % on your phone. Swipe again and the HUD comes back.

Noice! Didnt know this!!

 

[ed1nh0]

Just for the record, this video was made 11 months ago, so there was no Mavic on the market yet.
But, concerning the D-Log subject, this guy show basic diffs between some settings and how to use scopes (on Davinci Resolve) to guide you recover brighter and darker areas on post-production, tweaking and/or applying LUTs.
I think it might be a good idea to share it with you guys.

 

[ecoleman]

Just for the record, this video was made 11 months ago, so there was no Mavic on the market yet.
But, concerning the D-Log subject, this guy show basic diffs between some settings and how to use scopes (on Davinci Resolve) to guide you recover brighter and darker areas on post-production, tweaking and/or applying LUTs.
I think it might be a good idea to share it with you guys.

Casey Faris is just selling LUTS. He'll tell you whatever you want to hear to sell his products. He's also the same guy that recommends shooting with -2 sharpness which has now been established is a really bad idea.

Here's another view of D-Log Vs D-cinelike, although I would disregard his recommendation of applying -1 sharpness as it's been established that this causes the watercolour effect.

 

[ed1nh0]

He's also the same guy that recommends shooting with -2 sharpness which has now been established is a really bad idea.

I agree with you. And I don't want to buy his LUTs and didn't mean too. Indeed it's a bad idea to set sharpness that way, but take note that the video was made 11 months ago.
The video you posted is also very good and helpful to watch.
Thanks for share.

 

[Strafe1]

I get terrific video shooting in D-Cinelike, and good video shooting in D-Log or Art. I also keep my sharpness at -1, or 0 at the most. Not all Mavics experience the same color problems identically. Some people have to have sharpness at +1 just to get a useable image. Others don't need to do this at all. I think you really have to experiment with your own Mavic, under a variety of shooting conditions. It's the classic "your mileage may vary" scenario. For me, D-Cinelike with -1,-1,-1 settings is perfect under normal (not too contrasty) conditions. I also like to shoot at +0.3 EV. It doesn't stress the compression algorithm too much and allows me a little room to manipulate the lights and darks. I prefer to not use LUTs since all my scenes seem to be different. I get good video with D-Log, but I have to work harder to get the same result as D-Cinelike. And a little luck is involved since the Mavic sensor and algorithm can't always recover the flat image. Again, YMMV!