ISO performance on SL2-s vs SL2

[hansvons]

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@hdmesa can’t agree more!

[davidmknoble]

At the end of the day, measuring tells all.  Photos to Photons has a pretty scientific measurement system with a lot of data.  Here is the comparison of the SL2 vs SL2-S of dynamic range vs. ISO.  Even if you don’t believe the actual dynamic range, the difference between sensors is real, at essentially all ISO’s.  The better the range, typically the less the noise.

https://www.photonstophotos.net/Charts/PDR.htm#Leica SL2,Leica SL2-S

 It is clear the native ISO of the SL2-S is 100 not 50, and I use 100 as my low ISO, but you could also argue that 50 provides the same ISO, but the key is the ISO of the SL2-S is about a stop ahead of the SL2.  Whether it shows up is a function of enlargement because noise is also pixel based.  So, you could also argue that the SL2 won’t show the noise as fast as the SL2-S.  But, in my use, I can keep highlights in more extreme light better with the SL2-S, which is why I prefer it for landscape work.  Depends on usage for sure!

So, I think the difference is that from a hardware perspective the SL2-S is ahead in noise and dynamic range, from a print perspective, the SL2 won’t show the noise as quickly, but the dynamic range still may not suit all users.

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[SrMi]

3 hours ago, davidmknoble said:

At the end of the day, measuring tells all.  Photos to Photons has a pretty scientific measurement system with a lot of data.  Here is the comparison of the SL2 vs SL2-S of dynamic range vs. ISO.  Even if you don’t believe the actual dynamic range, the difference between sensors is real, at essentially all ISO’s.  The better the range, typically the less the noise.

https://www.photonstophotos.net/Charts/PDR.htm#Leica SL2,Leica SL2-S

 It is clear the native ISO of the SL2-S is 100 not 50, and I use 100 as my low ISO, but you could also argue that 50 provides the same ISO, but the key is the ISO of the SL2-S is about a stop ahead of the SL2.  Whether it shows up is a function of enlargement because noise is also pixel based.  So, you could also argue that the SL2 won’t show the noise as fast as the SL2-S.  But, in my use, I can keep highlights in more extreme light better with the SL2-S, which is why I prefer it for landscape work.  Depends on usage for sure!

So, I think the difference is that from a hardware perspective the SL2-S is ahead in noise and dynamic range, from a print perspective, the SL2 won’t show the noise as quickly, but the dynamic range still may not suit all users.

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When comparing two cameras using P2P, you should consider that the ISO is not normalized across cameras. That means the curves may be shifted left/right to compare the two cameras correctly. 

ISO 50 on SL2 and Q2 is tricky, and I avoid it. But we do have more DR at ISO 50. The answer to whether ISO 50 is native or not is irrelevant if most people avoid it anyway,

There is no doubt that SL2-S has less noise and allows better shadow lifting than SL2. The question is how much we can mitigate SL2's disadvantage using the latest NR tools.

[kobra]

4 hours ago, davidmknoble said:

At the end of the day, measuring tells all.  Photos to Photons has a pretty scientific measurement system with a lot of data.  Here is the comparison of the SL2 vs SL2-S of dynamic range vs. ISO.  Even if you don’t believe the actual dynamic range, the difference between sensors is real, at essentially all ISO’s.  The better the range, typically the less the noise.

https://www.photonstophotos.net/Charts/PDR.htm#Leica SL2,Leica SL2-S

 It is clear the native ISO of the SL2-S is 100 not 50, and I use 100 as my low ISO, but you could also argue that 50 provides the same ISO, but the key is the ISO of the SL2-S is about a stop ahead of the SL2.  Whether it shows up is a function of enlargement because noise is also pixel based.  So, you could also argue that the SL2 won’t show the noise as fast as the SL2-S.  But, in my use, I can keep highlights in more extreme light better with the SL2-S, which is why I prefer it for landscape work.  Depends on usage for sure!

So, I think the difference is that from a hardware perspective the SL2-S is ahead in noise and dynamic range, from a print perspective, the SL2 won’t show the noise as quickly, but the dynamic range still may not suit all users.

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Thanks for sharing this @davidmknoble I have a question you or others may be able to answer... (I've asked on DPR but didn't get an answer)

What does "scaling" mean on this chart? I ask because the chart shows scaling (triangle up) for the SL2, starting at ISO 3200, but it does not show scaling at all for the SL2-S. 

My experience on the SL2 seems to show that the image changes a lot between ISO 1600 to ISO 3200, and I've been disappointed in some low light ISO3200 images (surprised a bit as from my research I expected more from ISO3200). 

So, does anyone know what scaling means and how that affects ISO and IQ at about 3200 on the SL2?

Thanks for helping me understand this better!

Brad

 

 

[jrp]

I imagine that scaling means that the sensor is "ISO invariant" at the settings that have adjacent triangles.  That is, it makes no difference whether you change exposure in camera or in your raw editing app.

[jaapv]

Basically it means a separate amplifier for intermediate ISO values. It allows the designers to assign different amplification algorithms for different ISO ranges, making the sensor non-ISO invariant.

[kobra]

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Ok, I think I'm confused... for the SL2 is the sensor "non-ISO invariant" or "ISO invariant"? 

Thanks!

Brad

[SrMi]

From Bill Claff on scaling in SL2 (DPR post):

“Up  triangles are scaling that appears to be done by the firmware after the Analog to Digital Converter (ADC) has been read.”

[SrMi]

5 minutes ago, kobra said:

Ok, I think I'm confused... for the SL2 is the sensor "non-ISO invariant" or "ISO invariant"? 

Thanks!

Brad

Almost no camera is ISO invariant over the whole ISO range. Many cameras are almost ISO invariant above a certain ISO. For SL2 that is ISO 800.

[kobra]

4 hours ago, SrMi said:

Almost no camera is ISO invariant over the whole ISO range. Many cameras are almost ISO invariant above a certain ISO. For SL2 that is ISO 800.

Thanks guys! 

Getting back to the original topic... clearly the charts are different for the 2 cameras. If we set aside the "extra stop" on the chart when we compare the DR of the 2 cameras, what practical difference does it make to the DR when we compare the sensor of the SL2 (scaling) vs the SL2-S (no scaling). 

I'm still trying to better understand the differences we are discussing here. 

Thanks again! 

Brad

[LocalHero1953]

On 4/6/2023 at 8:05 PM, hdmesa said:

• If you don't need the higher resolution of the SL2, the SL2-S is a no-brainer.
• If you need high resolution, why would you want an SL2-S?
• If you need both resolution and the highest-quality ISO, why not wait for the SL3?

I don't like introducing AI noise reduction to the equation since it can be used on either camera to further improve the output from each. I also don't like the overly-smooth and blended "oil paint quality" of AI noise smoothing.

To me, the quality of noise is more important to me than the quantity of noise. To that end, I do not like the look of the noise from high ISO images from the SL2 and Q2 (at or above 6400 in low light) – even converting them to black and white does not fully satisfy me. The noise from the SL2-S at high ISOs is very filmic and pleasing to me.

Also when looking at samples people provide, don't confuse high ISO performance in good light versus high ISO performance in very low light.

A solid common sense post! Totally agree.

[davidmknoble]

6 hours ago, kobra said:

Thanks guys! 

Getting back to the original topic... clearly the charts are different for the 2 cameras. If we set aside the "extra stop" on the chart when we compare the DR of the 2 cameras, what practical difference does it make to the DR when we compare the sensor of the SL2 (scaling) vs the SL2-S (no scaling). 

I'm still trying to better understand the differences we are discussing here. 

Thanks again! 

Brad

Brad, I had the SL2 for about a year.  I shoot a lot of travel, but I also shoot a lot on the coast of the Eastern US.  What I found was I could never get the highlights and shadows balanced well enough to get a print (or output) that I liked.  I use graduated filters and other methods to reduce the light range (because I also shoot film and it is just a better capture if you can lower the highlights and boost shadows before you press the shutter).  I would find shadows in the rocks or crested waves that just didn't pull out enough detail or the highlights in the foamy water or skylit water would be white with no detail.  Yet, I could get the range and the detail with my S007 / S3, so I knew it was there.  So, I sold the SL2 and got the SL2-S.

With the SL2-S, I don't have that problem and I can get more images that I can be happy with.  To be clear, my biggest problem was high dynamic range light and also very early light (pre-sunrise).  From a detail perspective, a 4,000 x 6,000 pixel sensor, at 250 dpi (english, not metric) gives me a 16 x 24 print size with zero software help, or at 300 dpi 13 x 20 (13 x 19 paper).  I do find that very slight enlargement by the right software doesn't hurt and my largest paper size in my epson printer is 17 x 24.  And if all that isn't good enough, if I have a still subject (not the ocean!) I can use the multi-image offset to get a larger sized image.

So, I don't need the size and I can print really large prints on my own.

All that said, and the lower cost of the SL2-S makes good sense as I love the M11 sensor and it is the closest to an S camera I have every used.  If the M11 sensor were in an SL body, I would by it on the spot. I don't know what makes the SL2-S so much less expensive, but the only difference I see is the sensor.

[LocalHero1953]

An interesting thread.
If it shows anything, it is that camera tests are great at measuring the parameters they measure 😉. They not great at mirroring the experience of users.

This is not to denigrate the tests or the testers, but it shows that there are a lot more factors involved in creating a camera we like than than simple things like dynamic range, pixel density etc. There are noise patterns, colour quality and, no doubt, other things that we haven't yet separated out and articulated from the mush that is our eye-brain complex.

[BernardC]

12 hours ago, SrMi said:

Almost no camera is ISO invariant over the whole ISO range. Many cameras are almost ISO invariant above a certain ISO. For SL2 that is ISO 800.

To be clear, most sensors now have "dual native ISO", which is a second signal path much like a "line" and "mic" input on audio amplifiers. That was a Panasonic innovation, which they introduced on their professional video cameras (VariCam and EVA-1). Sensors are invariant within these two ranges.

Here is Panasonic's page on the topic: https://na.panasonic.com/us/audio-video-solutions/broadcast-cinema-pro-video/dual-native-iso-camera-technology-cinematic-low-light-video-production

[SrMi]

1 hour ago, BernardC said:

To be clear, most sensors now have "dual native ISO", which is a second signal path much like a "line" and "mic" input on audio amplifiers. That was a Panasonic innovation, which they introduced on their professional video cameras (VariCam and EVA-1). Sensors are invariant within these two ranges.

Here is Panasonic's page on the topic: https://na.panasonic.com/us/audio-video-solutions/broadcast-cinema-pro-video/dual-native-iso-camera-technology-cinematic-low-light-video-production

Almost all still cameras have dual conversion gain sensors using Aptina technology (whitepaper).

Video cameras use the dual output gain described in the linked Panasonic page. Panasonic GH6 is the only still camera using that technology, AFAIK. Its high ISO performance is not that good.

While DPR is still alive, you can read a comparison here.

[SrMi]

On 4/6/2023 at 11:05 AM, hdmesa said:

If you don't need the higher resolution of the SL2, the SL2-S is a no-brainer.

When do you need a higher resolution?

I always need higher resolution, regardless of how large or small my print is and whether I want to crop more or less.

I have both SL2-S and SL2. I typically use SL2-S when I work in low light. It is always better to start with the least noise in an image. However, I am still investigating whether the latest AI NR gives me fewer artifacts with higher-resolution sensors.

The comparison I posted before is just one situation and may or may not be typical.

[hdmesa]

54 minutes ago, SrMi said:

When do you need a higher resolution?

I always need higher resolution, regardless of how large or small my print is and whether I want to crop more or less.

I have both SL2-S and SL2. I typically use SL2-S when I work in low light. It is always better to start with the least noise in an image. However, I am still investigating whether the latest AI NR gives me fewer artifacts with higher-resolution sensors.

The comparison I posted before is just one situation and may or may not be typical.

"Need" versus "prefer" for me. I would prefer to have the 60mp M11 sensor in an SL3 and in the Reporter finish  That said, I still prefer the images from the SL2-S at low ISO even over those I get from my M11, as good the M11 is. I would expect the difference there is mainly due to available profiles in C1/LR.

[davidmknoble]

I think a good use case for the higher resolution is when you need to crop more than a 18-24mp sensor might want.  I know, you might say "get closer," but that does not work at the edge of a deep gorge, or at the edge of the ocean, or on the deck of a ship.  It does allow for a lower lens selection and crop to get the missing focal lengths.  So, you could use a 35 and a 75 and effectively have a 50 and a 90 in very reasonable ending resolution.

What I like about the M11 sensor is the dynamic range and color.  Out of the camera the DNG files don't need as much tweaking and they are very, very close to the S3.  I still have work to do on the SL2-S files but in my mind they are a strong second.  If you add the adapters, that is what makes the SL system so great and flexible.

[Ken Abrahams]

Great posts and info about the DR of the two SL (and S) cameras. I found myself having to use amy friends GND filter on the APO SL 35 yesterday. It's the problem with clouds higher up in the frame while the foreground and subject are in the shadows. I call it a "shadow pit". The sun is moving in and out of clouds above and behind so managing the exposures can be tricky. The clouds are going to clip most of the time as they have the brightest illumination compared to the foreground and subject. I have a clipping limit set marginally below 255 so if I see a bit of clipping I know I am in the ball park. 

The 0.6 GND sorted the issue out for the SL2 however my friend mentioned how he gets clipping on his SL2 while his S2 (which is set up in the same shooting position) does not show clipping. My M10M does not show clipping in the same scene like the SL2. Given that the range of luminance in the scene is vast I have always managed to get a good exposures on the SL 601 and M10M using with M lenses.  I am already looking into another filter system for the Apo SL 35 because I love shooting with this lens.  Otherwise I could just purchase the SL2s and alternate the cameras like some have said above.

This image has had a fair bit of post processing but I like the dramatic/surreal look and my clouds must have usable detail  

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Edited April 9, 2023 by Ken Abrahams

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[cope07]

FWIW:

I’ve used both. The SL2 is basically a base ISO camera for me.  Even then the DR doesn’t handles skies well, but the color and resolution is very nice. At ISO 800 I find shadows are not useable if lifted (ugly purple noise (even after LR’s built in NR). That’s not a super high ISO for me (especially if I want to use f/2 lenses instead of 1.4 for size/weight). 
 

the SL2-S can basically be used as a ‘normal’ modern 24MP camera (like a z6, a7iv, d750, etc): you have a pretty full range of ISO to play with and competitive DR at base ISO 

 

 

I ended up selling both. I got some images on the SL2 whose color I loved but that camera was too limited and AF-C was even less consistent than a DSLR when I needed. 
The SL2-S never produced an image that wowed me, 24MP from 45 (of my d850) was rough to swallow and again the AFC. 

Edited April 9, 2023 by cope07