Is the sensor in the Leica SL2 ISO Invariant?

[JESan]

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Hello all, I am trying to find out if the Leica SL2 sensor is ISO invariant. Do any of you know of a reference that addresses this question? I am likely going to run some tests myself to validate afterwards.

Cheers!

John

[Jeff S]

You might find interest in this discussion as it progresses...

 

Jeff

[AphotoBerlin]

looks like it. (Dual Gain). Just don't get higher than ISO800 and you can just underexpose and push the picture in postproduction instead of raising the ISO. 

https://photonstophotos.net/Charts/PDR_Shadow.htm#Leica SL2

[jankap]

Interesting is the result of the Sigma fp in this chart.

[cboy]

55 minutes ago, jankap said:

Interesting is the result of the Sigma fp in this chart.

The fp has dual base iso at 100 & 3200 i understand. The shadow recovery is quite good in comparison to highlights which is 1 stop

Edited April 15, 2021 by cboy

[helged]

23 hours ago, AphotoBerlin said:

looks like it. (Dual Gain). Just don't get higher than ISO800 and you can just underexpose and push the picture in postproduction instead of raising the ISO. 

https://photonstophotos.net/Charts/PDR_Shadow.htm#Leica SL2

The largest challenge with SL2, as many/most sensors, is highlight clipping. The newer M10-R and S3 sensor (sharing the same sensor) is better in this respect. But care is still required.

[SrMi]

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9 hours ago, helged said:

The largest challenge with SL2, as many/most sensors, is highlight clipping. The newer M10-R and S3 sensor (sharing the same sensor) is better in this respect. But care is still required.

Highlight clipping is caused by exposure technique, not by sensor. If exposing manually, any camera can cause or avoid highlight clipping.

[helged]

1 hour ago, SrMi said:

Highlight clipping is caused by exposure technique, not by sensor. If exposing manually, any camera can cause or avoid highlight clipping.

Based on my experience, highlight clipping also depends on the sensor; some sensors are more prone to (harsh) clipping than others. So, again based on my experience, the different sensors need to be tested regarding clipping (based on M8, M9, M240, MM, M246, S006, S3, Panasonic S1, S5, S1R, and Nikon bodies). 

[SrMi]

7 hours ago, helged said:

Based on my experience, highlight clipping also depends on the sensor; some sensors are more prone to (harsh) clipping than others. So, again based on my experience, the different sensors need to be tested regarding clipping (based on M8, M9, M240, MM, M246, S006, S3, Panasonic S1, S5, S1R, and Nikon bodies). 

To my knowledge, this can't be if you consider how sensors work. If a sensel is over-saturated, the highlight will be clipped for that pixel, and nothing can recover the blown data. If it is not oversaturated, the data can be used. 

[helged]

3 hours ago, SrMi said:

To my knowledge, this can't be if you consider how sensors work. If a sensel is over-saturated, the highlight will be clipped for that pixel, and nothing can recover the blown data. If it is not oversaturated, the data can be used. 

Agree. Oversaturated pixels contain no data. But additional factors - like data processing in camera - are involved, yielding different apparence of highlights, not in the blown highlights, but in the transition from highlights without data in the three channels, to pixels with (some) information. Some sensors tend to produce very sharp transitions, others more even transitions. (Personally, I clearly prefer how highlights are treated by film.) The sensor/algorithms used in M10-R and S3 are among the better. Lumix S1R and Nikon D5 are (much) more problematic. 

[SrMi]

56 minutes ago, helged said:

Agree. Oversaturated pixels contain no data. But additional factors - like data processing in camera - are involved, yielding different apparence of highlights, not in the blown highlights, but in the transition from highlights without data in the three channels, to pixels with (some) information. Some sensors tend to produce very sharp transitions, others more even transitions. (Personally, I clearly prefer how highlights are treated by film.) The sensor/algorithms used in M10-R and S3 are among the better. Lumix S1R and Nikon D5 are (much) more problematic. 

Agreed. I also prefer how highlights are treated by film 😁.