Help Me (And Others) Understand Exposure/Low Light Shooting

The place for questions about shooting with Blackmagic Cameras.
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awppollock

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Re: Help Me (And Others) Understand Exposure/Low Light Shoot

PostTue Jan 12, 2021 4:29 am

Ric Murray wrote:It appears to me from this thread, and another posted elsewhere on this forum about depth of field, that awppollock is beginning a new chapter in the world of digital cinema cameras, as opposed to, perhaps, consumer equipment. There are a large number of overlapping issues he appears to be working on, lighting, tonal compression and underexposure, video compression and codecs, the relationship between lens settings and DOF, and the differences in streaming platforms. He seems like a thoughtful fellow with a thirst for knowledge, but this forum is perhaps not the most efficient way for him to learn the basics of shooting and post production. Could some of the posters here recommend reading material and/or Youtube channels where he may study these topics more efficiently?

I would also recommend to awppollock that he consider volunteering as an unpaid Production Assistant on any local indie productions, and try to work his way into the camera department. Watching others with a lot of experience in lighting, setting up shots, blocking, and production design is a great way to learn quickly at no cost at first, and then working your way up to $100/day as second AC is way less expensive than film school and hundreds of thousands in student loans. Don't get me wrong and start another argument here, I went to a very good art school myself, a very long time ago, and it was worth it. However, I see a lot of people in this forum and a few others that have bought a "professional" digital cinema camera and think that alone will make their images look like what they see on Netflix. If that were true, everyone who bought a good hammer at Home Depot would be a finish carpenter. As I said earlier, don't mistake a good tool for good craft. Best of luck, to you awppollock. Keep learning!


Thank you, yes, I am learning and there are evidently LOTS of issues colliding at once and it can be difficult to tell which one is the issue at a given juncture. I HAVE learned a lot here and an deeply grateful to everyone who has and who continues to post their thoughts and wisdom. Thanks to all!
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awppollock

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Re: Help Me (And Others) Understand Exposure/Low Light Shoot

PostTue Jan 12, 2021 4:37 am

Howard Roll wrote:Learning the difference between low light and low-key lighting would probably be a good place to begin gaining some understanding. https://en.wikipedia.org/wiki/Low-key_lighting

This example is low light, the results are unsurprising, the image has no contrast and the blacks are floating in space. Once the blacks are lowered there's almost nothing left and the subject is underexposed by about 4 stops. Additionally the light is all fill, there is no key light which is why she's underexposed 4 stops.

scopes.png


Further, if the subject had been kept camera left immediately following this grab the BG would be the lights in the room instead of the wall. She breaks the 180 rule for no reason then forces poor composition. I'd advise putting some conscious effort and thought into the lighting approach and blocking.

This on the other hand is what a proper low-key shot is supposed to look like.

Low-key_cat.jpg


The fill level is the same as the OP's grab with the addition of a hard key light. If the key light is coming from the direction of a practical source it is referred to in the larger industry as motivated lighting.

Nothing about BC Tipi's video is remarkable, limited dynamic range and crushed blacks, meh. This is basically day for night.

BC Tipi.png


Good Luck


I do appreciate the input. Thank you. She breaks the 180 rule because I have no idea what the hell that is yet haha. I appreciate the help. I am new to these crafts and do appreciate you all for offering your input, experience and guidance. The camping video is less of a stunning example of cinematography to me and more of a decent example of clean blacks/not a ton of light on Youtube without compression totally artifacting the heck out of it. Anyway, I appreciate the feedback and the examples you gave, thank you.
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awppollock

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Re: Help Me (And Others) Understand Exposure/Low Light Shoot

PostTue Jan 12, 2021 4:38 am

Oyvind Fiksdal wrote:
Robdoc wrote:Hi Alex, I don't mean to hijack your thread but I am learning (trying) to shoot dark shots as well. I have a BMPCC6K though and I wanted my shots to look like this:




I shot at 3200 Iso. From what I have read in these comments it seems best to shoot the scene with lots of light then in post make it darker? But I am just confused I guess on how those other shots look crystal clear with no noise while it is night outside with not a lot of light???


From my own experience.. Its about being bold with grading. Go bananas. Always keep in mind that what you get from BRAW files is pure RAW data without any filters. Not sexy. I always keep in mind when shooting "this is not representative to what i want". Because you have the chance to make it painterly good at your own control later on. That is, IF you have recorded enough data(Light).

Here is an example simulating "the witch" look from a shot i did this Christmas. Its shot at 3200ISO, afternoon(midday), in a dark forest at F2.8 40mm(equivalent).
witch_Pocketgrade.jpg




This is a screencap from the movie "The Witch" as reference.

thewitch_screencap.jpg



Here is the original flat straight out of cam.

forest-original.jpg


Very cool and informative. Thank you.
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Oyvind Fiksdal

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Re: Help Me (And Others) Understand Exposure/Low Light Shoot

PostTue Jan 12, 2021 9:00 am

Robdoc wrote:Yes, that is it. Tonal banding. I am not sure what could be doing that to the video. I even exported it from resolve as a different format and it still gives the tonal banding on the video. (I use the BMPCC6K)
The settings are:
Blackmagic RAW
Constant Bitrate
5:1
6K
Film


banding from a 12bit source viewed on a 8bit monitor is most likely cause by either the monitor or the delivered format (8bit). There are a couple of topics around discussing banding and how to avoid it.

This is what the tech guys from Davinci resolve is saying to solve such problems:
"add a Filter tool to the Fusion comp. Filter tool set to Noise, Power 2 or 3, turn off alpha, and low Blend of ~0.04, adjust to taste. That should break up the bands and won't change the image depth"

Also. It seem like people have been experiencing more of these issues on Macos rather than windows.. don’t know why... I’m using both and haven’t experienced it.
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Robdoc

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Re: Help Me (And Others) Understand Exposure/Low Light Shoot

PostTue Jan 12, 2021 8:57 pm

Oyvind Fiksdal wrote:
Robdoc wrote:Yes, that is it. Tonal banding. I am not sure what could be doing that to the video. I even exported it from resolve as a different format and it still gives the tonal banding on the video. (I use the BMPCC6K)
The settings are:
Blackmagic RAW
Constant Bitrate
5:1
6K
Film


banding from a 12bit source viewed on a 8bit monitor is most likely cause by either the monitor or the delivered format (8bit). There are a couple of topics around discussing banding and how to avoid it.

This is what the tech guys from Davinci resolve is saying to solve such problems:
"add a Filter tool to the Fusion comp. Filter tool set to Noise, Power 2 or 3, turn off alpha, and low Blend of ~0.04, adjust to taste. That should break up the bands and won't change the image depth"

Also. It seem like people have been experiencing more of these issues on Macos rather than windows.. don’t know why... I’m using both and haven’t experienced it.


Do you know where turn off alpha is? I do not see that in the filter noise node in Fusion.
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Ellory Yu

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Re: Help Me (And Others) Understand Exposure/Low Light Shoot

PostWed Jan 13, 2021 8:45 pm

Robdoc wrote:So I took the advice from what was mentioned on this thread and shot in light and then in post tried to grade it to it looks like dark/night.

The problem I am having is that the footage looks blotchy.

This footage below shows three different clips. One in raw and then one graded to look like it is night. Do you guys see the same I do with the blotchiness? Any idea what I am doing wrong?
I shot these at 400 iso with the sigma 18-35 lens.. The kitchen light was on above my wife. I had two Neewer Bi-Color Video LED lights pointing at her from each side too.



Hey Rob, Here's a screenshot of the test grade I did that took care of the banding and made it look like dark/night shot. Be aware I just did a very fast grade with the clip since I only put in a few minutes as I'm super busy this week. But I hope it will give you an idea what you can do with your shot and get a start. Good luck!

rctest.JPG
rctest.JPG (35.61 KiB) Viewed 113 times
MSI Raider X99 MB / Intel i7 5280 6 core CPU / 2 x AMD R9 390X 8Gb GPU / 32Gb 3200 RAM / Decklink 4K Mini Monitor / 240Gb SSD OS Drive / 4Tb RAID 0 SSD Cache/Scratch Drive / 24Tb 7200rpm HDD Data Drive / Win 10 Pro 64bit / Resolve 16.2.8
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Robdoc

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Re: Help Me (And Others) Understand Exposure/Low Light Shoot

PostFri Jan 15, 2021 2:01 am

Thanks so much for your time!
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