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Auto ISO and max shutter speed not working?


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Hi, if I use the A shutter speed and maximum ISO of 6400ISO and 1/125s as max shutter speed (in Auto ISO setting), and it's dark, the Q2 goes above 1/125 to 1/8, 1/4, etc... why this weird behaviour? On the Q1 when you set the max shutter speed to 1/125 it keeps 1/125 and display a very dark image in the viewfinder but it doesn't change the shutter speed alone.

I'm missing something/doing wrong or is it a bug?

Thanks!

Edited by giuliomagnifico
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17 minutes ago, giuliomagnifico said:

Hi, if I use the A shutter speed and maximum ISO of 6400ISO and 1/125s as max shutter speed (in Auto ISO setting), and it's dark, the Q2 goes above 1/125 to 1/8, 1/4, etc... why this weird behaviour? On the Q1 when you set the max shutter speed to 1/125 it keeps 1/125 and display a very dark image in the viewfinder but it doesn't change the shutter speed alone.

I'm missing something/doing wrong or is it a bug?

Thanks!

I think it is the intended behavior. Raise max Auto-ISO to max value if you do not want the shutter speed to go down. For example, staying at ISO6400 at 1/125 while underexposing by one stop (instead of dropping shutter speed to 1/60) is similar to exposing at ISO 12500 @ 1/125.

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I don’t understand, the Q2 doesn’t underexpose by 1 step, it changes to 1/60, 1/30, 1/15, 1/8, etc… also if I configured the auto ISO max value to 1/125. 
 

Instead it should stay at 1/125 and display a dark image inside the EVF, like the Q1 did. 

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32 minutes ago, giuliomagnifico said:

I don’t understand, the Q2 doesn’t underexpose by 1 step, it changes to 1/60, 1/30, 1/15, 1/8, etc… also if I configured the auto ISO max value to 1/125. 
 

Instead it should stay at 1/125 and display a dark image inside the EVF, like the Q1 did. 

Assume a scene light where Q2 meters ISO 6400 at 1/60 while Q1 meters ISO 6400 at 1/125. In that case Q1’s image is underexposed by 1 stop. In most cases it would be better/similar to shoot with ISO 12500 at 1/125 than with ISO 6400 at 1/125.

If you do not want slower shutter speed to counter lower light, then it is better to set Auto-ISO to its max value. If you want to limit the amount of noise, then Q2’s approach is the only solution (increase exposure).

AFAIK, most cameras implement Q2’s approach. IMO, it makes more sense.

Why don’t you want to set higher max-ISO limit?

 

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3 hours ago, SrMi said:

If you do not want slower shutter speed to counter lower light, then it is better to set Auto-ISO to its max value. If you want to limit the amount of noise, then Q2’s approach is the only solution (increase exposure).

🤨 I still don't understand... this is not a way to limit the amount of noise if it goes above my 6400ISO.

 

3 hours ago, SrMi said:

Assume a scene light where Q2 meters ISO 6400 at 1/60 while Q1 meters ISO 6400 at 1/125. In that case Q1’s image is underexposed by 1 stop. In most cases it would be better/similar to shoot with ISO 12500 at 1/125 than with ISO 6400 at 1/125.

But I don't want the Q2 shoot above 1/125s at 6400ISO, and it's impossible to keep this setting, also if the Q2 settings report "Max shutter speed time", what's the point of this setting if it isn't respected/considered?!

 

3 hours ago, SrMi said:

Why don’t you want to set higher max-ISO limit?

Because I want to switch from A shutter speed to manual (using the time ring) with the time slower than 1/125 that I want to use, not the camera that uses the time it wants! Because sometimes I shoot in macro mode and I don't want the camera to shoot slower than 1/125, I want to choose by myself when I have to shoot slower than 1/125.

 

This setting inside the Q2 is pointless, maybe it's a firmware bug if there's this setting but it isn't respected.

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1 hour ago, giuliomagnifico said:

 I still don't understand... this is not a way to limit the amount of noise if it goes above my 6400ISO.

The noise does not depend on the ISO but the exposure (aperture and shutter speed). Therefore, the ISO limit will not limit the max noise unless the camera lowers the shutter when ISO limit is reached.
Q2's technique (decrease shutter speed when ISO limit is reached) limits the noise. However, Q1's technique does not limit the noise since the noise increases as the image is underexposed. So I do not see any benefit in Q1's approach.

1 hour ago, giuliomagnifico said:

Because I want to switch from A shutter speed to manual (using the time ring) with the time slower than 1/125 that I want to use, not the camera that uses the time it wants! Because sometimes I shoot in macro mode and I don't want the camera to shoot slower than 1/125, I want to choose by myself when I have to shoot slower than 1/125.

Your comment does not explain why you do not set a higher max ISO for Auto-ISO. If you are OK with Q1's ISO 6400 at 1/125 and one-stop underexposed, then you should be OK with ISO 12500 at 1/125. The ISO 12500 shot will have the same noise as the ISO 6400 shot.

1 hour ago, giuliomagnifico said:

This setting inside the Q2 is pointless, maybe it's a firmware bug if there's this setting but it isn't respected.

IMO, Q2's implementation is the correct one and has been implemented in most cameras, AFAIK.

Q2's implementation allows limiting the amount of noise by decreasing the shutter speed when necessary—if noise limit is not the goal, then setting the ISO limit to its max value will keep the shutter limit as long as possible.

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Small correction:
noise is NOT increased when the camera sticks to a fixed max iso and shutter speed and, as a consequence, underexposes the image.

Noise is increased when the photographer brightens the image in post-processing afterwards, to get the actually desired exposure.

 

But I do agree:
the sensor in the Q2 is basically what we call ISO-invariant, so it doesn't care about iso (unlike my very old Canon 1Ds mk III) and uses it to increase the exposure as if you were just doing it in post-processing.

 

That said, I would also prefer it if the camera underexposes instead of slowing the shutter speed.

But it might be better to just use auto iso in manual mode and let the camera adjust for the correct exposure while you control aperture and shutter speed.

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Posted (edited)
4 hours ago, SrMi said:

The noise does not depend on the ISO but the exposure (aperture and shutter speed). Therefore, the ISO limit will not limit the max noise unless the camera lowers the shutter when ISO limit is reached.
Q2's technique (decrease shutter speed when ISO limit is reached) limits the noise. However, Q1's technique does not limit the noise since the noise increases as the image is underexposed. So I do not see any benefit in Q1's approach.

Your comment does not explain why you do not set a higher max ISO for Auto-ISO. If you are OK with Q1's ISO 6400 at 1/125 and one-stop underexposed, then you should be OK with ISO 12500 at 1/125. The ISO 12500 shot will have the same noise as the ISO 6400 shot.

IMO, Q2's implementation is the correct one and has been implemented in most cameras, AFAIK.

Q2's implementation allows limiting the amount of noise by decreasing the shutter speed when necessary—if noise limit is not the goal, then setting the ISO limit to its max value will keep the shutter limit as long as possible.

But this is not the point, I simply want to change from the maxium automatic 1/125 sec to 1/60 manually when the Q2 reaches the maximum configured ISO of 6400 and it shows a dark image in the EVF. But the Q2 is not working in this way (despite the menu name), it changes the exposure time (lowering it to 1/60, 1/4, etc..) by itself.

Since I photograph moving people, the camera became annoying to use if it doesn't respect my/your settings!

What the point of having a menu called "maxium exposure time" if the camera change it by itself as it prefers? Looks like more a bug than a feature to me. If I want to use higher ISO I should simply change the maxium ISO setting.

 

I'm not discussing about "what in theory is better" but "what I want to do with a setting in the Q2 that -instead- isn't working as it should" 🙄😡

Edited by giuliomagnifico
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7 hours ago, mbphotox said:

Small correction:
noise is NOT increased when the camera sticks to a fixed max iso and shutter speed and, as a consequence, underexposes the image.

Noise is increased when the photographer brightens the image in post-processing afterwards, to get the actually desired exposure.

 

But I do agree:
the sensor in the Q2 is basically what we call ISO-invariant, so it doesn't care about iso (unlike my very old Canon 1Ds mk III) and uses it to increase the exposure as if you were just doing it in post-processing.

 

That said, I would also prefer it if the camera underexposes instead of slowing the shutter speed.

But it might be better to just use auto iso in manual mode and let the camera adjust for the correct exposure while you control aperture and shutter speed.

There are two Auto-ISO strategies, Q1's (nobody uses it?) and Q2's (all manufacturers use it?):

Q1: Shutter speed stays the same. The Auto-ISO setting (ISO limit) has no effect except for making the image darker. The IQ result is the same as if there were no Auto-ISO limit. However, it needs brightening in the post.

Q2: Shutter speed increases once the Auto-ISO limit is reached. The Auto-ISO setting determines the max. allowable noise in the image.

I do not see the point in Q1's approach, especially if not setting Auto-ISO to max ISO value.

As you suggested, using Misomatic mode (Auto-ISO in M mode) is a low light solution if you need to stay at a shutter speed, regardless of IQ.

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6 hours ago, giuliomagnifico said:

But this is not the point, I simply want to change from the maxium automatic 1/125 sec to 1/60 manually when the Q2 reaches the maximum configured ISO of 6400 and it shows a dark image in the EVF. But the Q2 is not working in this way (despite the menu name), it changes the exposure time (lowering it to 1/60, 1/4, etc..) by itself.

Since I photograph moving people, the camera became annoying to use if it doesn't respect my/your settings!

What the point of having a menu called "maxium exposure time" if the camera change it by itself as it prefers? Looks like more a bug than a feature to me. If I want to use higher ISO I should simply change the maxium ISO setting.

 

I'm not discussing about "what in theory is better" but "what I want to do with a setting in the Q2 that -instead- isn't working as it should" 🙄😡

Solution: set Auto-ISO to the max ISO value.

Using EVF brightness to judge the image exposure is unreliable. A better approach would be to set Auto-ISO to max ISO value, and when the ISO display in the EVF shows a value higher than 6400, change manually to 1/60 to keep the noise in control (operator's choice of lowering shutter speed, instead of forced by camera).
Why do you set the ISO limit at 6400 instead of the max possible value? If I understand correctly, you will accept increased noise to eliminate subject movement blur.
In Q1's approach, the ISO value in Auto-Setting has no meaning. The final result after brightening is the same as if there were no ISO limit.

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I can only check with M11, which does the same as Q2, but I assume that all Leica cameras do it the same way as Q2 (and Sonys and Nikons).

IMO, Q1’s implementation is a bug.

P.S: This Auto-ISO concern is raised for other non-Leica cameras regularly. The conclusion is always the same: it is better this way.

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No it's not better for me, it's better on other cameras that don't have the shutter speed ring, but with the ring like the Q/M is way better to respect the user setting and if the user want to brighten the photo or change the shutter speed, it can be done by simply rotate from A to 1/60sec.

This is because sometimes I make portraits in macro mode, and I can't use shutter speed below 1/125s, I prefer to view by myself when the image is too dark I can't take the photo, but in the Q2 I have to check both the ISO (if I set the maxium ISO at 50k is not usable for me), and the shutter speed that it isn't below 1/125, and this take more time than know that the camera has respected your settings and it keeps the is at 6400 (or 1-2 steps above) with a speed of 1/125.

This is not how I make my street photos, and this will make me to change how I take some photos.

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37 minutes ago, giuliomagnifico said:

No it's not better for me, it's better on other cameras that don't have the shutter speed ring, but with the ring like the Q/M is way better to respect the user setting and if the user want to brighten the photo or change the shutter speed, it can be done by simply rotate from A to 1/60sec.

This is because sometimes I make portraits in macro mode, and I can't use shutter speed below 1/125s, I prefer to view by myself when the image is too dark I can't take the photo, but in the Q2 I have to check both the ISO (if I set the maxium ISO at 50k is not usable for me), and the shutter speed that it isn't below 1/125, and this take more time than know that the camera has respected your settings and it keeps the is at 6400 (or 1-2 steps above) with a speed of 1/125.

This is not how I make my street photos, and this will make me to change how I take some photos.

One last comment on the topic from my side :) (unless you ask for clarification):

On Q2, ISO 50000 gives you a slightly better image than ISO 6400 with 3 stops underexposed and lifted three stops in the post (Q1 approach). If you let ISO go as high as possible, you will get slightly better images than stopping at ISO 6400 and 1/125 while allowing the camera to underexpose.

Have you tried M-mode  (1/125) with Auto-ISO? It simulates what Q1 does, except that it does not increase the shutter speed if there is too much light.

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Agreeing mit SrMi here.

Shoot in manual mode when you are constantly faced with low light anyways.
Set the shutter manually, select your aperture, and have the camera chose the iso value.

If you cannot live with iso above 6400, then you shouldn't even shoot images in that light. It's that easy.

 

Underexposing (because you desperately want to stay below iso 6400 at all cost) and then pushing the exposure up will result in the same or a worse image than if you let the camera expose at a higher iso from the start.

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Yes my problem is not set the camera in M mode, with Q1 when I saw all dark in the EVF, I switched the ring to 1/60-1/30... this is not the trouble, trouble now is that when I'm shooting in macro mode (where 1/125 is the time limit to avoid blurred pics) now I don't see all dark inside the EVF, the camera changes itself the shutter time, and I see a normal image, but it takes the photo at 1/4-2"etc... and it's all blurred when I zoom it. As I wrote, I have to check everytime the shutter speed, is less quick than view all dark inside the EVF.

This is my only complaint, yes I can rise the auto ISO to the max but the result will be the same: noise instead blur. Instead if I see all dark I can avoid to take the photo, or I can manually change to 1/60 and be careful about the motion, or disable the Macro mode (and shoot at f1.7 instead 2.8) etc...

I found a bit silly how the Q2 handles/doesn't respect your settings. I'm trying to say this, but it's my opinion and my way to take pictures, other people with other techniques maybe like it.      

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