M10-Mono Base ISO?

[ldhrads]

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Probably been asked, but since I just received mine, what's the base ISO for the M10-Mono?  I don't want to be "Pulling"

 

Thanks

 

Lawrence

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[padam]

 

[Chips]

On 2/20/2021 at 9:31 AM, padam said:

 

When I got my M10 Monochrome -- the base ISO was reported as 160 which was a big improvement over the previous 340 ISO. That's my sense but others will be far more competent to comment. It really is a terrific camera! CHIPS

[Chips]

I also use a ND filter to get the ISO down to where I can make photos at longer exposures. I have a Noctilux and use an ND filter during daylight hours.  CHIPS

[Jeff S]

42 minutes ago, Chips said:

When I got my M10 Monochrome -- the base ISO was reported as 160 which was a big improvement over the previous 340 ISO. That's my sense but others will be far more competent to comment. It really is a terrific camera! CHIPS

You might read the linked thread in post #2.

Jeff

[SrMi]

Base ISO of M10 Monochrom seems to be 160.

PhotonsToPhotos measures highest DR at ISO 160: link.

The lowest ISO used in Auto ISO mode is also ISO 160. No camera manufacturer uses pulled ISOs when in Auto-ISO mode, AFAIK.

AFAIK, Sean Reid is using highlight headroom to determine base ISO. That is not the right way to determine base ISO (i.e.,  ISO with the best SNR).

[adan]

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44 minutes ago, SrMi said:

That is not the right way to determine base ISO (i.e.,  ISO with the best SNR)

That's only half the story - as is highlight headroom.

The key word in dynamic range is "range" - how many stops in total, from end to end, can be captured. without losing detail to blown highlights - or  shadows to "excess" noise (the noise floor).

https://en.wikipedia.org/wiki/Noise_floor

When I tested ISO 100 and 200 with my M10, I looked for a very high-brightness-range scene - deep inky shadows, and also bright specular highlights (sun reflecting off polished bronze)

At ISO 100, the SNR was very good in the deepest shadows (virtually no noise) - but the specular highlight headroom was miserable.

At ISO 200, the highlight detail separation was a stop (or so) better - but the SNR was worse in the deepest shadows (more noise). Also by about a stop. So both those ISOs had effectively the same dynamic range, simply clipped at opposite ends of the range.

In other words, it is easy to keep improving the SNR by increasing the S(ignal) with more and more exposure - but if that results in blown highlights, it is pointless. Gotta measure at both ends.

The base ISO (or best ISO) was probably pretty close to Stefan Daniel's vague estimate of "about 135" - right in between ISO 100 and ISO 200 (but sadly, not actually a value one can select with the M10).

If I had an M10M of my own, I would do a similar test. (If you want something done right, do it yourself. )

- find a scene with an extreme brightness range (inky shadows, sunlit whites and near-whites, specular highlights). Ideally something with a brightness range of 13 stops or more.

- set the lowest available ISO and meter a gray card (only objective way to compare exposures with internal reflective meters). Photograph the gray card as a reference.

- Make an exposure of the scene.

- repeat at all the reasonable ISOs, being sure to include the "in-between" ISOs (125, 160, 250, 320, 500, 640) and not just the "round-number" dial ISOs (100-200-400-800).

-Take those dozen or so exposures and open them on the computer, and determine which ISO reveals both maximum noise-free shadow detail  and separable (unclipped) highlights. = Maximum dynamic range - to within a 1/6th stop or so.

BTW - this is an example of a 13-stop test scene (on film) - metered exposure EV13 in the sunlit textured white-tile wall, EV0 in the "shaded shadows" bottom center. FIlm, of course, "pulls" better than digital; this was a severe "pull" (meter the shadows, underexpose them 3 stops to "zone 2", give N-3 underdevelopment, get detail everywhere ).

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[SrMi]

53 minutes ago, adan said:

That's only half the story - as is highlight headroom.

The key word in dynamic range is "range" - how many stops in total, from end to end, can be captured. without losing detail to blown highlights - or  shadows to "excess" noise (the noise floor).

https://en.wikipedia.org/wiki/Noise_floor

When I tested ISO 100 and 200 with my M10, I looked for a very high-brightness-range scene - deep inky shadows, and also bright specular highlights (sun reflecting off polished bronze)

At ISO 100, the SNR was very good in the deepest shadows (virtually no noise) - but the specular highlight headroom was miserable.

At ISO 200, the highlight detail separation was a stop (or so) better - but the SNR was worse in the deepest shadows (more noise). Also by about a stop. So both those ISOs had effectively the same dynamic range, simply clipped at opposite ends of the range.

In other words, it is easy to keep improving the SNR by increasing the S(ignal) with more and more exposure - but if that results in blown highlights, it is pointless. Gotta measure at both ends.

The base ISO (or best ISO) was probably pretty close to Stefan Daniel's vague estimate of "about 135" - right in between ISO 100 and ISO 200 (but sadly, not actually a value one can select with the M10).

If I had an M10M of my own, I would do a similar test. (If you want something done right, do it yourself. )

- find a scene with an extreme brightness range (inky shadows, sunlit whites and near-whites, specular highlights). Ideally something with a brightness range of 13 stops or more.

- set the lowest available ISO and meter a gray card (only objective way to compare exposures with internal reflective meters). Photograph the gray card as a reference.

- Make an exposure of the scene.

- repeat at all the reasonable ISOs, being sure to include the "in-between" ISOs (125, 160, 250, 320, 500, 640) and not just the "round-number" dial ISOs (100-200-400-800).

-Take those dozen or so exposures and open them on the computer, and determine which ISO reveals both maximum noise-free shadow detail  and separable (unclipped) highlights. = Maximum dynamic range - to within a 1/6th stop or so.

BTW - this is an example of a 13-stop test scene (on film) - metered exposure EV13 in the sunlit textured white-tile wall, EV0 in the "shaded shadows" bottom center. FIlm, of course, "pulls" better than digital; this was a severe "pull" (meter the shadows, underexpose them 3 stops to "zone 2", give N-3 underdevelopment, get detail everywhere ).

<snip>

Blown highlights are determined by exposure, not by dynamic range. You can always expose so that the highlights are not blown.

What you are observing is the characteristics of the automatic exposure. To determine the DR, you need to expose manually so that the sensor is just saturated, i.e., no highlights are blown, and then look at the noise in the shadows.

 

[BrianS]

Blown highlights are determined by sensor saturation count.

You can have two cameras with the same Base ISO, shoot the same scene with the same exposure and have one camera blow the highlights and the other camera not clip the highlights. Different sensors have different saturation count. An example is the M8 vs the M9. The saturation count of the M8 is 50% higher than the M9, both have the same size pixels. Both have the same Base ISO. Use the same exposure on the two cameras, with the same scene: the M9 will saturate before the M8.

Edited February 23, 2021 by BrianS