Black Levels

[SrMi]

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In the PSAT (Photographic Science and Technology) subforum of DPR, Bill Claff discusses the importance of proper Black Level encoding in the EXIF of raw files:

"Correct BlackLevel in the Exif is important to get correct color hues at low light levels."

P2P has the Black Level Range on the Sensor Heatmaps page. That range measures the frame's black level relative to the EXIF value — Bill: "The closer to zero, the better. Anything above 1 is probably problematic for very deep shadows. "

These are the values for SL cameras (low and high gain):

SL at ISO 50: 0.68

SL at ISO 200: 0.312

--

SL2 at ISO 50: 1.587

SL2 at ISO 800: 0.943

--

SL2-S at ISO 100: 0.049

SL2-S at ISO 800: 0.180

--

SL3 at ISO 100: 0.255

SL3 at ISO 320: 0.185

 

Those numbers approximating deep shadows' quality match the forum's experience.

 

 

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[pf4eva]

Yeah, SL2 is very bad no question here...

[goodbokeh]

Trying to prop up the amnesic SL3 eh 🙂 Well, SrMi you're a consistent supporter I have to give you that.

BTW, I'm sure you know ISO 50 are "Pull" settings for the SL & SL2. According to Reid Reviews, which (unlike P2P) does real life tests, ISO 50 for the SL & SL2 are no bono. That setting results in detrimental blown highlights with no benefits in the shadows.

This is just another P2P over analysis going down the wrong path with a misleading conclusion. I've seen other examples of P2P foul balls on cameras. Possessing raw data does not mean it's being measured or interpreted correctly.

[SrMi]

14 minutes ago, goodbokeh said:

Trying to prop up the amnesic SL3 eh 🙂 Well, SrMi you're a consistent supporter I have to give you that.

BTW, I'm sure you know ISO 50 are "Pull" settings for the SL & SL2. According to Reid Reviews, which (unlike P2P) does real life tests, ISO 50 for the SL & SL2 are no bono. That setting results in detrimental blown highlights with no benefits in the shadows.

This is just another P2P over analysis going down the wrong path with a misleading conclusion. I've seen other examples of P2P foul balls on cameras. Possessing raw data does not mean it's being measured or interpreted correctly.

ISO 50 is weird, but it is not a pull ISO setting. Bill measured better PDR for ISO 50 with SL2 and SL. Forum members also noticed better DR and Jim Kasson measured it. Pull ISOs cannot provide better DR. Instead, it seems like the sensor is operating in the nonlinear area, which affects highlights if you do not expose it properly (added correction to default metering). 

Sean Reid's methodology for determining native ISO is not correct. It may work in some cases.

Regardless, that should not affect the validity of shadow analysis. The data for high gain is also provided in case you believe ISO 50 is problematic.

I do not understand where you see anything misleading. 

The numbers also match what we see in those cameras: SL2-S seems slightly better in deep shadows than SL3 and much better than SL2. Of course, the quality of deep shadows is not always what matters most.

 

 

[goodbokeh]

Yes SiMi when you give a sensor too much light weird things do happen. It's just too bad P2P doesn't test using the manufacturer's base ISO of a camera rather than a self proclaimed hat pull of ISO 50. But go ahead and believe all of P2P's charts and say Sean Reid doesn't know what he's talking about. I don't buy it.

[SrMi]

58 minutes ago, goodbokeh said:

Yes SiMi when you give a sensor too much light weird things do happen. It's just too bad P2P doesn't test using the manufacturer's base ISO of a camera rather than a self proclaimed hat pull of ISO 50. But go ahead and believe all of P2P's charts and say Sean Reid doesn't know what he's talking about. I don't buy it.

For your education, this is the weirdness of ISO 50 (or ISO 100 in monochrome):

https://blog.kasson.com/leica-q2-monochrom/should-you-use-iso-100-on-the-leica-q2-monochrom/

P2P does not depend on manufacturers' data, and to the best of my knowledge, Leica has never officially stated its base ISO for SL2 or Q2. I subscribe to Reid Reviews and like reading his articles, but I do not think they are gospels. In the area of photographic science and technology, more competent people are out there.

I have used facts to explain why ISO 50 is not pull-ISO in the traditional sense. Feel free to address the facts instead of arguing about "authorities."

 

[SrMi]

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2 hours ago, pf4eva said:

Yeah, SL2 is very bad no question here...

I would say weaker, not very bad.