Scarlet Dragon Noise Floor Issue

[Mark S Sanders]

Hey Redusers,

This is my first post on Reduser, but I've been reading things on this forum for a long time. I'd love to get some opinions on this from the truly knowledgeable community here.

I just received my new Scarlet Dragon this week, and I am noticing a strange image flicker or fluctuation in heavily underexposed situations. It's hard to explain but I think that after looking at the R3D you will be able to see it too. This is the link to the R3D: https://drive.google.com/file/d/0B_jmW-mTqLN0eUxjd2RlUWxWazA/view?usp=sharing

It looks to me almost as if the image is fluctuating slightly in terms of brightness, and there are some slight color shifts going on. After walking around my house and my yard with the camera, I can confirm that this only happens when the image is underexposed, the more underexposed it is the more intense this effect becomes. I sent a similar R3D to RED's support team, and they told me that after running some tests and viewing the camera log that this is not a hardware issue, and that it's normal - that basically this is what happens when the sensor hits it's noise floor. Now, noise is something I fully expect at 3200 ISO. So obviously it will be unbearably bad if the image is underexposed at that ISO, I get that. But what about this flicker/fluctuation thing that's going on? Does anybody else see this?

For example, obviously it's not ideal to underexpose like this but let's just say that I am shooting a doc, I have to shoot in a dimly lit situation and I am hitting the noise floor, and I can't add any light. Yes there will be noise. But am I just stuck with this flicker? Because if that's true it renders this camera useless in low light documentary situations.

This is my first RED cam, and so I'll be the first to admit that there will be some getting used to and that there will be a learning curve. Luckily these forums are a great resource and I have learned a lot on here. But this just doesn't seem normal to me. What do you guys think?

 

[Charles Bergquist]

Yes I've had the same response from RED. It's not a "hardware issue" it's just how the sensor performs, i.e. the flickering. To test the situation, exaggerate it so you can clearly see it, set the camera to 12,800 ISO and leave the lens cap on.

 

[Michael Tiemann]

Hey Redusers,

This is my first post on Reduser, but I've been reading things on this forum for a long time. I'd love to get some opinions on this from the truly knowledgeable community here.

If you have been reading these forums for a long time, you know that RED cameras need light to operate properly.

I just received my new Scarlet Dragon this week, and I am noticing a strange image flicker or fluctuation in heavily underexposed situations. It's hard to explain but I think that after looking at the R3D you will be able to see it too. This is the link to the R3D: https://drive.google.com/file/d/0B_jmW-mTqLN0eUxjd2RlUWxWazA/view?usp=sharing

If you just received a stock SCARLET DRAGON, then it probably has the Skin-Tone-Highlight OLPF, which means it works best at ISO 320, though it will tolerate being pushed to about ISO 800. If you replace the STH OLPF with the Low-Light-Optimized (LLO) OLPF, you can stretch that to ISO 2000 before noise starts to rise. ISO 3200, underexposed, using the STH OLPF is going to be very noisy indeed. I have seen this; I know.

It looks to me almost as if the image is fluctuating slightly in terms of brightness, and there are some slight color shifts going on. After walking around my house and my yard with the camera, I can confirm that this only happens when the image is underexposed, the more underexposed it is the more intense this effect becomes. I sent a similar R3D to RED's support team, and they told me that after running some tests and viewing the camera log that this is not a hardware issue, and that it's normal - that basically this is what happens when the sensor hits it's noise floor. Now, noise is something I fully expect at 3200 ISO. So obviously it will be unbearably bad if the image is underexposed at that ISO, I get that. But what about this flicker/fluctuation thing that's going on? Does anybody else see this?

There is now D.E.B. (DRAGON-Enhanced-Black) which helps curtail a good bit of noise in DRAGON images. It's been available in RED CINE-X since the summer, and recently supported now in Resolve 11.1, too.

Here's a great example of what can be done with ISO 12800 if you really know your post-processing workflow: http://www.reduser.net/forum/showthread.php?120575-Red-Epic-Noise-Reduction-test-at-ISO-12800

Note that in that video, the scenes are not underexposed: they are properly exposed for the ISO, and they are brilliantly processed--and noise-reduced--in post.

For example, obviously it's not ideal to underexpose like this but let's just say that I am shooting a doc, I have to shoot in a dimly lit situation and I am hitting the noise floor, and I can't add any light. Yes there will be noise. But am I just stuck with this flicker? Because if that's true it renders this camera useless in low light documentary situations.

This is my first RED cam, and so I'll be the first to admit that there will be some getting used to and that there will be a learning curve. Luckily these forums are a great resource and I have learned a lot on here. But this just doesn't seem normal to me. What do you guys think?

D.E.B. will help you crush down your blacks so that an underexposed scene looks underexposed. It works well enough that it will make your exposure, not the camera's sensor, look bad.

If you need to shoot low-light documentary footage, for example, using moonlight to shoot a surf documentary, there are other cameras better suited to the task: https://vimeo.com/109262022

The DRAGON is a brilliant camera within its normal ISO limits, and it can be stretched with software some stops beyond that. But you are asking for all kinds of trouble if you are shooting STH @ ISO 3200 while underexposing the scene.

I, too, once thought "hey, it would be so great to have a camera that doesn't need lights". I have come to learn that lighting is what makes the image, not merely in terms of filling photosites on the sensor, but by really defining the scene that is to be recorded.

Here's a great example of low-light documentary that is not no-light documentary: http://www.reduser.net/forum/showth...Sharp-Art-of-Amazing-Selection-Stills-and-BTS

That example shows that with a little foresight and fore-thought, the light can be where it needs to be, and yet appear to be invisible/not there to the casual observer (or the subject himself).

 

[Aria Khosravi]

There is definitely a slight flicker in the noise pattern on Dragon that was not present on MX, and as Charles said, you can raise the ISO to really see it in action. I remember people discussing it in the early days of the Dragon.

Having used Sony cams like the A7S and F5/55 I can tell you that those cams have really bad noise flicker and the ugliest moving noise patterns, albeit with a much lower noise floor that makes it less of an issue. So yes, it flickers, it's an issue, but not one unique to the Dragon.




And not to go off-topic or sour the mood (I know some people are going to get upset about this) but the Dragon is one of the last cameras I would pick for low-light documentary work anyway. It really isn't designed for that, neither from a form factor nor image perspective.
I'm not saying it can't be done -- several successful and great-looking documentary films have been shot partially on the Epic and there are some REDusers shooting doc material with the Dragon now -- but that there are better options out there for that specific sort of work. There is a reason that for strictly low light work the go-to documentary cams right this minute are the C300 and the F5/55.

At any rate, if you think you'll be doing that sort of work on this camera, you definitely need to get the Low-Light Optimized OLPF to at least get you an extra stop or so before you hit the noise floor. When shooting 5K/6K, the LLO OLPF will give you slightly cleaner images than an Alexa or Arri Amira, and you'll have better resolution and color science in a smaller package than the C300 and Sony.

 

[Nick Morrison]

There is definitely a slight flicker in the noise pattern on Dragon that was not present on MX, and as Charles said, you can raise the ISO to really see it in action. I remember people discussing it in the early days of the Dragon.

Having used Sony cams like the A7S and F5/55 I can tell you that those cams have really bad noise flicker and the ugliest moving noise patterns, albeit with a much lower noise floor that makes it less of an issue. So yes, it flickers, it's an issue, but not one unique to the Dragon.




And not to go off-topic or sour the mood (I know some people are going to get upset about this) but the Dragon is one of the last cameras I would pick for low-light documentary work anyway. It really isn't designed for that, neither from a form factor nor image perspective.
I'm not saying it can't be done -- several successful and great-looking documentary films have been shot partially on the Epic and there are some REDusers shooting doc material with the Dragon now -- but that there are better options out there for that specific sort of work. There is a reason that for strictly low light work the go-to documentary cams right this minute are the C300 and the F5/55.

At any rate, if you think you'll be doing that sort of work on this camera, you definitely need to get the Low-Light Optimized OLPF to at least get you an extra stop or so before you hit the noise floor. When shooting 5K/6K, the LLO OLPF will give you slightly cleaner images than an Alexa or Arri Amira, and you'll have better resolution and color science in a smaller package than the C300 and Sony.

You've mentioned this, but I'm very optimistic for the lowlight potential of the LOWLIGHT OLPF. As Phil and Bjorn have pointed out, it's possible to get usable 5000iso, which sounds like more than I'd ever need!

 

[Aria Khosravi]

You've mentioned this, but I'm very optimistic for the lowlight potential of the LOWLIGHT OLPF. As Phil and Bjorn have pointed out, it's possible to get usable 5000iso, which sounds like more than I'd ever need!

Day 2 with the LLO for me. It has a different look than the STH, roll-off is less smooth and more MX-like for exteriors and stuff, but it's a world of difference in noise level and noise pattern. Even in tungsten the noise is less colorful and less blotchy than the STH OLPF. At least 1.3 stops quieter in daylight. I was rating STH at 320 always, now very comfortable with 800 on LLO. Definitely cleaner than the Alexa/Amira at equivalent ISOs, cleaner than MX in daylight and tungsten. And as you know noise is subjective... 5000 can be 'usable' to some but it won't be 'clean' per se, unless you actually exposed the sensor in such a way that all the shadow areas were above the noise floor at say 800... Then you can push as far as you'd like without introducing noise. Again, depends on your tolerance for noise -- Don't go expecting to rate 1600-5000 and underexpose!

That's all I'll say for now about the LLO because I don't want to hijack the thread. But it definitely will help out OP with his noise problems.