M11 intermittent over exposure

[andybarton]

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If you shoot a digital image at an inappropriate ISO, you can adjust the exposure in post processing, but it’s not as good as shooting at an appropriate ISO in the first place.  

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[SrMi]

Just now, andybarton said:

If you shoot a digital image at an inappropriate ISO, you can adjust the exposure in post processing, but it’s not as good as shooting at an appropriate ISO in the first place.  

Why not? My tests and experience say differently. If you do not blow highlights and are in the ISO-invariant range, the IQ is the same as long as you keep the exposure constant. We are talking about DGNs, correct?

[andybarton]

Of course DNGs.

If that is true, why bother having a variable ISO in-camera? Just shoot at 100 ISO, or whatever the base sensitivity is, and crank it up to 11 in Lightroom.

[SrMi]

Just now, andybarton said:

Of course DNGs.

If that is true, why bother having a variable ISO in-camera? Just shoot at 100 ISO, or whatever the base sensitivity is, and crank it up to 11 in Lightroom.

Good question. ISO's primary role for DNGs is to maintain helpful brightness of the image and to switch the conversion gain. 

This graph shows how much shadow noise improves by increasing ISO while keeping the exposure constant. We see a significant improvement from ISO 160 to 200 (dual conversion gain point). Otherwise, the shadow noise is not significantly affected (ISO invariant ranges). Keeping the ISO lower than metered can avoid unnecessary highlight clipping without increasing noise. The disadvantage is that the images need to be brightness adjusted in the post before being reviewed (it is easy to do in Lightroom, batch mode).

ISO is needed for JPEGs and the dual conversion gain switch. Photographers dream of having two ISO cameras with a metatag added to the raw to automatically apply proper brightness in post. That would make the EVFs more useful while avoiding highlight clipping.

 

 

[andybarton]

1 minute ago, SrMi said:

Photographers dream of having two ISO cameras

Do they?

[SrMi]

1 minute ago, andybarton said:

Do they?

OK, not all photographers dream of it 😁, only those who understand how the ISO works and see the potential of such a solution.

The camera can still use user-facing gradually changing ISO, but internally, it would use only two ISOs. Imagine that practically any clipped highlight at ISO 1600 becomes recoverable without the image being dark because we needed to "underexpose" to preserve highlights.

[lct]

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1 hour ago, andybarton said:

If you shoot a digital image at an inappropriate ISO, you can adjust the exposure in post processing, but it’s not as good as shooting at an appropriate ISO in the first place.  

Define appropriate iso. See the snap i took last night. No problem for choosing aperture as i had an f/2 lens, so f/2. No problem for shutter speed either as i had no tripod on hand, so 1/15s. Now what iso to choose? 1600iso? Too dark. 3200iso? too dark again. 6400iso? Yes probably but risk of banding with the camera i had then (M240). Better let the camera decide with sole risk of having to adjust exposure in PP, so auto iso M mode was the obvious choice for me (M240, Summicron 50/2 v1, 4000iso). YMMV.

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[crons]

5 hours ago, SrMi said:

Some call manual mode setting with Auto ISO “Misomatic” mode as it is clearly not manual mode. Still, it is one of the most powerful modes available on contemporary cameras

While the made up term "Misomatic" mode might be powerful for certain situations, it still doesn't provide the full control that true manual mode offers, which is essential for mastering exposure and achieving consistent, professional results.

 

5 hours ago, SrMi said:

The overexposure issue with Auto ISO or automatic mode is a bug in M11, it is not something that occurs in other Ms, SLs, or Qs

If the overexposure issue with Auto ISO on the M11 persists despite Leica's firmware fix, it's likely a specific problem with that camera. Both the moderator and I have tried to explain this, but clearly, you're not getting it and for this issue not switching to manual settings for better contro as a basic workaround is just idiotic. Repeating it is an M11 bug doesn't solve his issue which is what this thread is about. Helping someone. 

Edited July 3, 2024 by crons

[crons]

2 hours ago, lct said:

Define appropriate iso. See the snap i took last night. No problem for choosing aperture as i had an f/2 lens, so f/2. No problem for shutter speed either as i had no tripod on hand, so 1/15s. Now what iso to choose? 1600iso? Too dark. 3200iso? too dark again. 6400iso? Yes probably but risk of banding with the camera i had then (M240). Better let the camera decide with sole risk of having to adjust exposure in PP, so auto iso M mode was the obvious choice for me (M240, Summicron 50/2 v1, 4000iso). YMMV.

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Simply register for free here – We are always happy to welcome new members!

 

Appropriate ISO is the setting that balances the sensor's sensitivity to light to achieve a well-exposed image, considering both brightness and image quality. Your approach with auto ISO in manual mode shows a lack of understanding of how to control exposure effectively, relying instead on trial and error that could be better managed with manual adjustments.

It's not like those trees are moving so fast you don't have an extra second to find your ISO. 

In this snapshot as you said the shutter speed doesn't matter because it's on a tripod and nothing is moving. Also depending on the lens, f2 may not give someone the desired results either (depending on the picture he wants to take) because it doesn't perform well there or introduces shallow depth of field that he doesn't want. 

So for this shot I would set my ISO to one im comfortable with. ISO800 for example, and then adjust the other settings accordingly. Since the shutter speed doesn't matter then I can also adjust the aperture to f4. Your results would've been much better than that have you just gone to full manual settings. 

Edited July 3, 2024 by crons

[lct]

Different experience here. I use auto iso M mode in the vast majority of my shots with all my digital camera since 2015 more or less. Challenging lighting are situation where it justifies the more for me. See the shot below with Tri-Elmar 28-35-50/4 on M11. Again, but perhaps my English is not good enough to explain, auto iso M mode allows you to set apertures as well as shutter speeds manually. You can even set iso values manually if you wish, in which case the only thing automatic are shutter speeds actually. YMMV.

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Edited July 3, 2024 by lct

[crons]

20 minutes ago, crons said:

In this snapshot as you said the shutter speed doesn't matter because it's on a tripod and nothing is moving. Also depending on the lens, f2 may not give someone the desired results either (depending on the picture he wants to take) because it doesn't perform well there or introduces shallow depth of field that he doesn't want

I will add in your snapshot this is exactly what happened. Your trees are dark and blurry and the sky look dull. If it's RAW maybe the sky can be enhanced but there's nothing you can do about the trees now. You can see the image falling apart in the trees and that’s most of the picture. 

Automatically choosing f/2 at night with auto ISO reveals a limited understanding of how aperture impacts depth of field and exposure control, often resulting in missed opportunities to optimize settings for better image quality.

Edited July 3, 2024 by crons

[lct]

4 minutes ago, crons said:

I will add in your snapshot this is exactly what happened. Your trees are dark and blurry and the sky look dull. If it's RAW maybe the sky can be enhanced [...] Automatically choosing f/2 at night with auto ISO reveals a limited understanding of how aperture impacts depth of field and exposure control [...]

Thanks no thanks the shot above is what i wanted but i won't insist any more since i cannot convince you anyway. As for your reference to my limited understanding, i'm not sure if you're qualified to tell this to someone with 50+ years experience of photography.

[crons]

7 minutes ago, lct said:

Thanks no thanks the shot above is what i wanted but i won't insist any more since i cannot convince you anyway. As for your reference to my limited understanding, i'm not sure if you're qualified to tell this to someone with 50+ years experience of photography.

I appreciate your experience in photography, but achieving optimal results involves understanding how aperture impacts depth of field and image quality. The noisy blurry trees in your photo suggest that maximizing aperture isn't always the best approach for achieving clarity and detail, especially in low-light conditions.

Respectfully, experience in photography is valuable, but techniques and understanding evolve over time. Using optimal settings like aperture for depth of field can enhance clarity and detail in low-light shots, ensuring the best possible results regardless of experience level.

Edited July 3, 2024 by crons

[crons]

54 minutes ago, lct said:

Different experience here. I use auto iso M mode in the vast majority of my shots with all my digital camera since 2015 more or less. Challenging lighting are situation where it justifies the more for me. See the shot below with Tri-Elmar 28-35-50/4 on M11. Again, but perhaps my English is not good enough to explain, auto iso M mode allows you to set apertures as well as shutter speeds manually. You can even set iso values manually if you wish, in which case the only thing automatic are shutter speeds actually. YMMV.

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

 

Thanks for sharing your extensive experience, though this thread is focused on addressing the issues faced by the M11 user with random overexposed images. Your insights on auto ISO in manual mode are noted, but let's stay focused on troubleshooting solutions for their specific problem. The snapshots of trees you keep sharing as examples don't quite illustrate the clarity and control we're aiming for here.

Edited July 3, 2024 by crons

[crons]

5 hours ago, andybarton said:

If you shoot a digital image at an inappropriate ISO, you can adjust the exposure in post processing, but it’s not as good as shooting at an appropriate ISO in the first place.  

Correct again.Selecting an appropriate ISO setting when capturing DNG files ensures optimal image quality with maximum dynamic range and minimal noise, reducing the need for extensive post-processing adjustments, a control best achieved in full manual mode. 

[SrMi]

17 minutes ago, crons said:

Correct again.Selecting an appropriate ISO setting when capturing DNG files ensures optimal image quality with maximum dynamic range and minimal noise, reducing the need for extensive post-processing adjustments, a control best achieved in full manual mode. 

Noise is determined mainly by exposure, not by ISO. You can verify that with simple tests (keep exposure constant and vary ISO). 

BTW: Increasing ISO in manual mode either decreases noise or keeps it unchanged.

[crons]

25 minutes ago, SrMi said:

Noise is determined mainly by exposure, not by ISO. You can verify that with simple tests (keep exposure constant and vary ISO). 

BTW: Increasing ISO in manual mode either decreases noise or keeps it unchanged.

The statement suggesting that noise is mainly determined by exposure, not by ISO, and that increasing ISO in manual mode either decreases noise or keeps it unchanged oversimplifies the complex relationship between exposure settings, ISO sensitivity, and noise in digital photography.

In reality, noise in photographs results from various factors, including exposure settings and ISO. Exposure settings, such as aperture and shutter speed, directly impact the amount of light that reaches the camera sensor. In low-light conditions, longer exposures or wider apertures can capture more light but may also introduce noise if not properly balanced. ISO sensitivity, on the other hand, determines how sensitive the camera sensor is to light. Higher ISO settings amplify the sensor's signal, including both the desired light and any inherent electronic noise, leading to potentially increased noise levels in the final image.

While it is true that keeping exposure settings constant and varying ISO can demonstrate how ISO affects noise levels, this does not discount the significant impact of exposure settings themselves on noise. Adjusting ISO in manual mode does not necessarily decrease noise—it typically increases sensitivity to light, which can amplify both the signal and noise captured by the sensor. Modern cameras incorporate noise reduction algorithms to mitigate noise at higher ISO settings, but noise remains a factor that photographers must consider when selecting ISO values.

Ultimately, achieving optimal image quality involves a nuanced understanding of how exposure settings and ISO interact to balance noise, brightness, and detail in photographs. It requires careful adjustment of both exposure settings and ISO to suit the lighting conditions and desired creative outcome, ensuring minimal noise while maintaining the integrity of the captured image.

Edited July 3, 2024 by crons

[kiwidad]

19 hours ago, SrMi said:

Fixed ISO is still automatic in A mode.

ISO is not part of the exposure; it is applied after exposure. The exposure consists of shutter speed, aperture, and scene lighting.

ISO is mainly responsible for the image brightness, which can blow the highlights if set or computed incorrectly.

When I set my ISO manually it doesn't change when I use A mode(I assume your referring to aperture priority mode?)

How exactly do you mean ISO is applied afterward? Is the sensors light sensitivity a constant or does it change?

The Sensitivity (ISO) of the sensor is a product of gain and thus it is fixed at time of exposure by a setting on the camera, so the exposure consists of ISO, shutter and aperture recording scene lighting

ISO determines the range of recorded light striking the sensor that is captured! RANGE not just the highlights. Choose the wrong range (ISO) and and incorrect aperture and shutter speed and you will can lose highlights or shadow detail recorded by the sensor

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[kiwidad]

19 hours ago, SrMi said:

Fixed ISO is still automatic in A mode.

ISO is not part of the exposure; it is applied after exposure. The exposure consists of shutter speed, aperture, and scene lighting.

ISO is mainly responsible for the image brightness, which can blow the highlights if set or computed incorrectly.

When I set my ISO manually it doesn't change when I use A mode(I assume your referring to aperture priority mode?)

How exactly do you mean ISO is applied afterward? Is the sensors light sensitivity a constant or does it change?

The Sensitivity (ISO) of the sensor is a product of gain and thus it is fixed at time of exposure by a setting on the camera, so the exposure consists of ISO, shutter and aperture recording scene lighting

ISO determines the range of recorded light striking the sensor that is captured! RANGE not just the highlights. Choose the wrong range (ISO) and and incorrect aperture and shutter speed and you will can lose highlights or shadow detail recorded by the sensor

[PeterKelly]

Any chance of getting this thread back to my original topic …….?

Edited July 3, 2024 by PeterKelly