Is visible noise in the viewfinder normal

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wemrick1

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Is visible noise in the viewfinder normal

PostMon Jan 24, 2022 8:53 pm

Have visible noise on both the flip out monitor and evf on my Ursa Mini 4k. Is this normal?
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wemrick1

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Re: Is visible noise in the viewfinder normal

PostMon Jan 24, 2022 11:41 pm

Been searching around the forum and with googoo and I think I have the answer. Yes, normal. I was warned this was no low light camera but I had no idea to what degree. It plain don't like shadows. That's ok. Now that I know what to expect it will be fine.
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Jamie LeJeune

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Re: Is visible noise in the viewfinder normal

PostTue Jan 25, 2022 1:52 am

Yup. I'd set that camera no higher than 400 ISO, and you can't push the exposure in post. The global shutter is nice, but that does come at a cost in terms of light sensitivity.
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wemrick1

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Re: Is visible noise in the viewfinder normal

PostTue Jan 25, 2022 2:07 am

Jamie LeJeune wrote:Yup. I'd set that camera no higher than 400 ISO, and you can't push the exposure in post. The global shutter is nice, but that does come at a cost in terms of light sensitivity.


Man, you got that right. Even at 400 with any amount of underexposure It's a mess. It was really worrying me. I used both false colors and the histogram just now with a very well lit subject. That did it. Not a trace of noise that I can see. Even in shadowed areas it's clean. Strange camera. I've never had a two ISO camera before, lol. Regardless, when you feed it enough light it comes with a beautiful image.
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rick.lang

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Re: Is visible noise in the viewfinder normal

PostTue Jan 25, 2022 2:57 am

The false colours are perhaps more reliable to judge an image in the shadows than using the histogram. The ‘native’ ISO is 400 and best to use that value as Jamie mentioned, controlling light to ensure there’s no purple except where you expect to be near black for your deliverables. Nothing wrong with black, but keep the shadows dark grey or just turning blue when you want details to be visible in your grade.

The histogram will certainly show you black but you don’t know where in the frame that’s happening. False Colour will tell you what and where it is unlit and you determine if that’s okay or not.
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wemrick1

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Re: Is visible noise in the viewfinder normal

PostTue Jan 25, 2022 3:19 am

rick.lang wrote:The false colours are perhaps more reliable to judge an image in the shadows than using the histogram. The ‘native’ ISO is 400 and best to use that value as Jamie mentioned, controlling light to ensure there’s no purple except where you expect to be near black for your deliverables. Nothing wrong with black, but keep the shadows dark grey or just turning blue when you want details to be visible in your grade.

The histogram will certainly show you black but you don’t know where in the frame that’s happening. False Colour will tell you what and where it is unlit and you determine if that’s okay or not.


That's pretty much the way my last two clips looked as I was filming. I appreciate you taking the time to give that detail. It will save a lot of trial and error. For the last two i didn't push things. I had two lights on each at about 45° from the camera and subject. Enough light to shoot at 2.8T, 24fps, 180° shutter and still keep away from the blues. Where I get confused with the false colors are the greys. Don't know if they are under or over mid grey.
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Overlander

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Re: Is visible noise in the viewfinder normal

PostTue Jan 25, 2022 4:15 am

Okay correct me if I am wrong but are we talking about the Ursa G2 4k? I thought the native ISO and recommend was 800. I just shot a lynx (wildcat) at 1200 in shade and it was a mess for sure. Just could not get it sharp at all.
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Howard Roll

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Re: Is visible noise in the viewfinder normal

PostTue Jan 25, 2022 4:46 am

Overlander wrote:…are we talking about the Ursa G2 4k?


BM never made a 4k G2. They’re talking about the original Ursa Mini 4k with the Cmosis 4k global sensor. The native iso on that cam was 400.

Good Luck
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Overlander

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Re: Is visible noise in the viewfinder normal

PostTue Jan 25, 2022 6:31 am

Thanks. I meant the G2 4.6K. Missed the .6.
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rick.lang

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Re: Is visible noise in the viewfinder normal

PostTue Jan 25, 2022 4:47 pm

The False Colour greys take some getting used to as occasionally I’ve mistaken one shade of grey for another. There’s dark grey just above blue and below green; medium grey between green (middle grey) and pink; and light grey above pink and below yellow. But the grey isn’t represented by three ‘solid’ shades as it is on a continuum of colour from very dark beside the blue to very light beside the yellow.

With experience it’s easier to know where you are. The BMPCC4K and BMPCC6K models now have a False Colour scale on the screen that helps, as of firmware 7.3.
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wemrick1

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Re: Is visible noise in the viewfinder normal

PostTue Jan 25, 2022 5:07 pm

rick.lang wrote:The False Colour greys take some getting used to as occasionally I’ve mistaken one shade of grey for another. There’s dark grey just above blue and below green; medium grey between green (middle grey) and pink; and light grey above pink and below yellow. But the grey isn’t represented by three ‘solid’ shades as it is on a continuum of colour from very dark beside the blue to very light beside the yellow.

With experience it’s easier to know where you are. The BMPCC4K and BMPCC6K models now have a False Colour scale on the screen that helps, as of firmware 7.3.


You nailed it once again. I think now it's a matter of spending time with the camera. I'm better understanding it's capabilities and limitations. I have one instance of noise I am going to have to research and try to figure out. It was a well exposed (pink to upper grey) with a 3 stop ND but shows horizontal lines of noise. It was cold out, like single digit F cold but I don't know if that is a factor. I just need to shoot some similar footage and see if I can duplicate the noise.
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rick.lang

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Re: Is visible noise in the viewfinder normal

PostTue Jan 25, 2022 6:00 pm

I wonder if that cold temperature is a factor with that sensor. Enough light but if the sensor is performing in cold weather like that, you may have exceeded the recommended operating temperature. I can’t recall what the recommendation is for that sensor but my guess is you’re too cold as that’s below -10 degrees Celsius. A lot of electronics are not going to perform well approaching your ambient temperature of a few degrees Fahrenheit. Sometimes you can keep the camera warm enough by wrapping it in a small blanket.
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wemrick1

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Re: Is visible noise in the viewfinder normal

PostTue Jan 25, 2022 7:06 pm

rick.lang wrote:I wonder if that cold temperature is a factor with that sensor. Enough light but if the sensor is performing in cold weather like that, you may have exceeded the recommended operating temperature. I can’t recall what the recommendation is for that sensor but my guess is you’re too cold as that’s below -10 degrees Celsius. A lot of electronics are not going to perform well approaching your ambient temperature of a few degrees Fahrenheit. Sometimes you can keep the camera warm enough by wrapping it in a small blanket.


Ya, I don't know. I'll do some more testing after it warms up a bit and let you know at least what I found. Right now we're in single digits F so I'm going to wait a bit to go back out.
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wemrick1

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Re: Is visible noise in the viewfinder normal

PostWed Jan 26, 2022 12:34 pm

rick.lang wrote:The false colours are perhaps more reliable to judge an image in the shadows than using the histogram. The ‘native’ ISO is 400 and best to use that value as Jamie mentioned, controlling light to ensure there’s no purple except where you expect to be near black for your deliverables. Nothing wrong with black, but keep the shadows dark grey or just turning blue when you want details to be visible in your grade.

The histogram will certainly show you black but you don’t know where in the frame that’s happening. False Colour will tell you what and where it is unlit and you determine if that’s okay or not.


Did some more testing with your instructions in mind and am now understanding the results. Exposed a scene with areas from red to purple last night. As the exposure progressed into the blue areas noise increased as per your observations. Going into dark blue and progressing into purple the noise and "flashing" (no idea what the proper term is) manifested as edge movement, i.e. the edge of a dark couch appeared to be moving and morphing against a much brighter wall background. Moving up the scale, grays started to be more acceptable with some noise reduction (25%) in Resolve.

It will be challenging for me to understand how to manipulate the blue/purple areas to achieve some of the wonderful low light footage I have seen where fire light is illuminating a subject. Obviously black is used along with grey and up and the troublesome blue/purple has been omitted/bypassed?

Amazing hobby! Plenty of meat here to work with. This should keep me busy for a good long time.
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Uli Plank

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Re: Is visible noise in the viewfinder normal

PostWed Jan 26, 2022 1:12 pm

First of all: no digital camera can record true black (other than a film camera).
So, shoot with enough light and contrast and generate black in post.
The software may be free, but the hardware needed for smooth performance is not.

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wemrick1

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Re: Is visible noise in the viewfinder normal

PostWed Jan 26, 2022 1:49 pm

Uli Plank wrote:First of all: no digital camera can record true black (other than a film camera).
So, shoot with enough light and contrast and generate black in post.

Got it! Makes sense.
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Re: Is visible noise in the viewfinder normal

PostWed Jan 26, 2022 2:22 pm

Uli Plank wrote:First of all: no digital camera can record true black (other than a film camera).
So, shoot with enough light and contrast and generate black in post.


I truly hope my continued babbling doesn't annoy you. It just hit me that I have an old pantax spot meter that is calibrated in IRE. I looked up the BM false color chart that relates to IRE. I am going to play with that this evening and see if the meter can be a helpful tool. Never used it for photography per built in spot meters on my cameras.
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Uli Plank

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Re: Is visible noise in the viewfinder normal

PostWed Jan 26, 2022 6:46 pm

Nobody is annoyed here, or we wouldn’t answer.
And trying to understand a scene in terms of spot metering will be a very good starting point.
The software may be free, but the hardware needed for smooth performance is not.

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wemrick1

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Re: Is visible noise in the viewfinder normal

PostWed Jan 26, 2022 6:59 pm

Uli Plank wrote:Nobody is annoyed here, or we wouldn’t answer.
And trying to understand a scene in terms of spot metering will be a very good starting point.


Thanks!

Ok, I found a BM false color chart that indicates that:

Red = 93 to 100 IRE
Orange = 84 to 93 IRE
>
Lower gray (under green) = 24 to 43 IRE
>
>Purple = -7 to 2 IRE

Thinking maybe by using a spot meter I could get a little more exact per understand which areas will not work well with this camera.

BTW: Reviewed your posts and I think the Broadcast G2 will be the next camera I look at now that I'm understanding things better.
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wemrick1

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Re: Is visible noise in the viewfinder normal

PostThu Jan 27, 2022 12:50 am

I'm rethinking the term low light. I just did a test at 3.5 EV which came out to about 12.5% in waveform and the noise was acceptable. That's not bad at all given the age of the camera and other systemic constraints. It wasn't long ago that 3.5 EV on a still camera would look much worse. Interesting.

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