Blackmagic Forum

Hey guys,

I've read that the "native" ISO for the URSA Mini Pro is 400. What does "native" mean? As far as my education has told me one should always set their ISO as low as possible in order to reduce noise. So for the URSA Mini Pro, why shoot on 400 ISO instead of 200 all other things being equal? Is 200 not the optimal setting?

It depends on what you are shooting, but the actual “native” ISO for the 4.6K sensor in the Ursa Mini/Pro is actually 800 for optional results and IQ. If shooting in Raw, ISO is just meta data, and you can change the exposure in post on Resolve. If shooting ProRes, changing the ISO only changes the mid level exposure value on a curve (exposure curve) relative to high and low exposure values.

Unlike many video cameras, changing ISO on BM cameras does not add or reduce analog Gain, which is actually fixed. While you are correct on cameras that add additional analog Gain as you crank up the ISO, keeping the ISO down improves the image quality. But since BM cameras have a fixed ISO/Gain level, changing ISO only changes the exposure curve, and does not add Gain.

So I would recommend doing some test shots, under the lighting conditions you normally use, to see which ISO level works best for your workflow. Start at 800, then shoot the same scene at 400 and again at 200.
Shooting at 1600 does increase the video noise levels somewhat.
Cheers

Denny Smith wrote:It depends on what you are shooting, but the actual “native” ISO for the 4.6K sensor in the Ursa Mini/Pro is actually 800 for optional results and IQ. If shooting in Raw, ISO is just meta data, and you can change the exposure in post on Resolve. If shooting ProRes, changing the ISO only changes the mid level exposure value on a curve (exposure curve) relative to high and low exposure values.

Unlike many video cameras, changing ISO on BM cameras does not add or reduce analog Gain, which is actually fixed. While you are correct on cameras that add additional analog Gain as you crank up the ISO, keeping the ISO down improves the image quality. But since BM cameras have a fixed ISO/Gain level, changing ISO only changes the exposure curve, and does not add Gain.

So I would recommend doing some test shots, under the lighting conditions you normally use, to see which ISO level works best for your workflow. Start at 800, then shoot the same scene at 400 and again at 200.
Shooting at 1600 does increase the video noise levels somewhat.
Cheers

Hi Denny, thanks for your advice as always. Just wondering: what exactly is "IQ" I've never heard of that term before? Also, when one says "native" and "best results" when speaking about ISO, what exactly are the benefits of using a camera's "native" ISO and the drawbacks of non-native ISO?

That's really interesting to know about the difference between BM cameras and other cameras in relation to ISO and grain. However, 1600 as you mentioned does add a bit of noise to the image but even more particularly it also adds a fairly noticeable FPN in the URSA Mini 4.6K sensor (verticle lines). Or perhaps this is just in low light... (more testing should clarify as I imagine FPN and grain behave differently).

James, IQ is short for intelligence quotient. Well that used to be the true meaning. But in the forum, the long form is probably image quality.


Sent from my iPhone using Tapatalk

Right, Rick, I meant image quality.

Yes James, FPN from what I see is mostly down to underexposure, which is what you are basically doing at 1600 in low light.
Cheers

If you rate the camera as 800 ISO, you'll get about the same range of stops above and below mid gray.
If you rate it lower, you'll get cleaner shadows at the cost of clipped highlights.
If you are shooting with tungsten lighting, I'd rate it at 400, but that could be just me.

rick.lang wrote:James, IQ is short for intelligence quotient. Well that used to be the true meaning. But in the forum, the long form is probably image quality.


Sent from my iPhone using Tapatalk

Haha, Rick, I'm aware IQ means intelligence quotient. I've studied quite a bit of statistical psychology. But yes it probably does mean something different when speaking about cameras. Image quality makes sense.

Then there is “EQ” — Emotion Quotient, the other side of the coin...
Cheers

Ha, ha! Equalizer! Next batter up!


Sent from my iPhone using Tapatalk

rick.lang wrote:Ha, ha! Equalizer! Next batter up!


Sent from my iPhone using Tapatalk

haha!

James McDonagh wrote:Hey guys,

I've read that the "native" ISO for the URSA Mini Pro is 400. What does "native" mean? As far as my education has told me one should always set their ISO as low as possible in order to reduce noise. So for the URSA Mini Pro, why shoot on 400 ISO instead of 200 all other things being equal? Is 200 not the optimal setting?

Blackmagic say 800.

I shoot mostly ProRes 444 and it's always at 800, even in very low light.

jb

James McDonagh wrote:As far as my education has told me one should always set their ISO as low as possible in order to reduce noise. So for the URSA Mini Pro, why shoot on 400 ISO instead of 200 all other things being equal?

I almost never change the ISO rating on my camera either, shooting pretty much always at ISO 800.

The way to avoid noise is to make sure you have good exposures.

John Brawley wrote:

James McDonagh wrote:Hey guys,

I've read that the "native" ISO for the URSA Mini Pro is 400. What does "native" mean? As far as my education has told me one should always set their ISO as low as possible in order to reduce noise. So for the URSA Mini Pro, why shoot on 400 ISO instead of 200 all other things being equal? Is 200 not the optimal setting?

Blackmagic say 800.

I shoot mostly ProRes 444 and it's always at 800, even in very low light.

jb

Hi John

There a reason you're shooting ProRes rather RAW? I see that both versions of 444 are higher data rates than RAW 4:1 and XQ is higher even than 3:1. Is that because productions are demanding ProRes, or do you find the quality to be better than compressed RAW?

Storage Rates
4608 x 2592
CinemaDNG RAW - 513MB/s
CinemaDNG RAW 3:1 - 180 MB/s
CinemaDNG RAW 4:1 - 135 MB/s
3840 x 2160
Apple ProRes 444 XQ - 250 MB/s
Apple ProRes 444 - 165 MB/s

Thanks!

Ian Henderson wrote:

John Brawley wrote:

James McDonagh wrote:Hey guys,

I've read that the "native" ISO for the URSA Mini Pro is 400. What does "native" mean? As far as my education has told me one should always set their ISO as low as possible in order to reduce noise. So for the URSA Mini Pro, why shoot on 400 ISO instead of 200 all other things being equal? Is 200 not the optimal setting?

Blackmagic say 800.

I shoot mostly ProRes 444 and it's always at 800, even in very low light.

jb

Hi John

There a reason you're shooting ProRes rather RAW? I see that both versions of 444 are higher data rates than RAW 4:1 and XQ is higher even than 3:1. Is that because productions are demanding ProRes, or do you find the quality to be better than compressed RAW?

Storage Rates
4608 x 2592
CinemaDNG RAW - 513MB/s
CinemaDNG RAW 3:1 - 180 MB/s
CinemaDNG RAW 4:1 - 135 MB/s
3840 x 2160
Apple ProRes 444 XQ - 250 MB/s
Apple ProRes 444 - 165 MB/s

Thanks!

The easy fast answer is

It’s easier and faster.

I shoot three cameras sometimes more per unit. That’s 5–6 hours of rushes per day for weeks on end.

Many post facilities gear their dailies setups for ProRes. For example, pretty sure colorfront (used by Lightiron for dailies) won’t read compressed DNGs.

PreRes is also hella good in 444. It’s 12 bit and doing 1920 ProRes also makes a bug difference to data rates of your above figures too.

90% of TV drama is not shot 4k despite the mythology.

JB

Thanks - helpful insight into the TV production world requirements.

John Brawley wrote:It’s easier and faster.

PreRes is also hella good in 444. It’s 12 bit and doing 1920 ProRes also makes a big difference to data rates of your above figures too.

I absolutely agree with this. Recording ProRes444 is one of the best features of the Ursa Mini Pro. ProRes files are so easy to run through post. Even that one producer/editor that I work with occasionally who is still stuck on FCP7 and using a 10 year old laptop can play the files no problem. Try that with anything from Red, or Canon or Sony, or Panasonic.

I also work as a colorist and as long as the white balance isn't 100% opposite of where it should be, there's virtually zero difference between ProRes444 and raw.

I think a lot of the benefits people see in raw is when they are comparing raw files to more compressed 8bit 4:2:0 or 10bit 4:2:2. But when you put raw back to back against 12bit 4:4:4 ProRes, it's damn hard to find cases where raw would actually yield a better result.

Did this comparison of raw versus ProRes 444 across ISO values:



password UM46K


Sadly I’ve been deleting my Vimeo videos now that the free version only allows a lifetime total of 5 GB of storage. Debating if I can afford the Plus account. I think Vimeo is the best place for me, but since all my work is pro bono, I hate subscriptions. At least my clients have their own sites and I upload very large files happily there.


Sent from my iPhone using Tapatalk

rick.lang wrote:Did this comparison of raw versus ProRes 444 across ISO values:



password UM46K


Sadly I’ve been deleting my Vimeo videos now that the free version only allows a lifetime total of 5 GB of storage. Debating if I can afford the Plus account. I think Vimeo is the best place for me, but since all my work is pro bono, I hate subscriptions. At least my clients have their own sites and I upload very large files happily there.


Sent from my iPhone using Tapatalk

How can you afford to only do ProBono work?!?! :O

James, I’m retired and trying to give back. I have been fortunate and blessed. I’m not doing commercial work pro bono that would be taking work from a professional; I’m doing work for people that could not afford to hire a professional, but appreciate having a high quality of video.

Sent from my iPhone using Tapatalk

rick.lang wrote:James, I’m retired and trying to give back. I have been fortunate and blessed. I’m not doing commercial work pro bono that would be taking work from a professional; I’m doing work for people that could not afford to hire a professional, but appreciate having a high quality of video.

Sent from my iPhone using Tapatalk

Excellent to hear that, Rick. Best wishes to you and happy retirement.

Rick is a man with joy in his heart and poetry in his mind.

Yes, yes he is...

And now back to our regular scheduled program... So, we can say the UM 4.6 sensor does best at ISO 800, while the UM4K is best at ISO 400. Now the question is, will BM follow Panasonic’s lead and come out with a new dual ISO sensor?
Cheers

800