Minimum shutter speed with auto iso setting?

[jayt]

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I can’t figure out how to set a minimum 1/125 shutter speed with 12,500 max auto iso setting? Anyone know the steps?local dealer did not know?

[adan]

Main Menu > ISO Setup menu > Maximum Exposure Time submenu.

There you can spec an absolute longest shutter speed to use (e.g. 1/125th sec) - OR a relative longest shutter speed to use, based on the focal length in use (as reported to the camera by 6-bit coding). E.G 1/f(ocal length) would give you 1/50th sec. or faster with a 50mm lens, whereas 1/4f(ocal length) would limit the slowest speed to 1/200th (50mm x 4).

HOWEVER - using the "A" mode on the shutter dial, the camera will drop below the chosen speed once it hits the upper limit set for an ISO to choose. I.E. if you set the top ISO to select automatically as 12500, and the light is so dim that ISO 12500 and your shutter speed limit would result in underexposure, the camera will use whatever shutter speed is needed for correct exposure (even if it is 1/4 sec.)

If you absolutely want the camera to never go below (or above) a certain shutter speed ever, even if that means underexposing (or overexposing) the picture - then set that speed on the manual shutter dial. The camera will select ISO as needed (i.e. still autoexpose for you) until it hits the 12500 limit, and then give you ISO 12500 and 1/125th no matter what - even if the resulting pictures come out pure black (or pure white).

All of that assumes that by "minimum" shutter speed you mean limiting the longest speed (to avoid camera shake).

Edited July 17, 2020 by adan

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[jayt]

Andy,

 

thank you so much will do. 

[sevsuk]

just got my Lieca m10, this is such a very useful post.  thanks.

[genefama]

I don't like the way Leica executes this. The shutter speed limit should be what the name suggests: the absolute limit. When I set the max ISO and minimum shutter speed I'm not asking the camera for a perfect 18% exposure come hell-or-high-water. A perfect exposure is great if it falls within my limits. Otherwise, the point of this setting is for the camera to NOT do what Leica cameras do in this situation: go below the shutter speed limit and give me motion blur. 

And yes I'm aware I can set everything but ISO manually but that doesn't actually find the best combination of ISO and shutter speed within my limits. It means I'm shooting everything at my slowest tolerable shutter speed when I'd really like the camera to feel free to exceed that (which you'd think would be the function of a setting that offers only the minimum and not both minimum and maximum).

All Leica cameras have this flaw so I don't expect it to change, meaning Aperture Priority doesn't actually exist for M cameras when it comes to street photography.

.

[ramarren]

@genefama: Seems to me that with my CL and M10-M, I can set either a relative maximum exposure time (1/f, 1/2f, etc) or a fixed maximum exposure time (1/125, 1/250, etc) ... that is, an absolute limit. So I have no idea what 'flaw' you're complaining about. Can you articulate more clearly?

thx, G

[Luke_Miller]

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On 9/5/2022 at 12:13 PM, genefama said:

All Leica cameras have this flaw so I don't expect it to change, meaning Aperture Priority doesn't actually exist for M cameras when it comes to street photography..

Actually, all cameras I am familiar with have this "flaw".  They disregard the slowest shutter speed setting in Auto ISO if necessary for correct exposure.  Adan in his post above has the solution to prevent motion blur.

Edited September 8, 2022 by Luke_Miller

[GuillaumeL]

Hi,

Chiming in here because I'm coming to Leica from other brands and the auto ISO feature surprised me as well. I agree with @genefama as I could not reproduce the behavior I knew in, say, Fuji X, with digital Ms (at least the 240 family).

In aperture priority with Auto ISO and a minimum shutter speed:

• Leicas seem to favor low ISO over high shutter speed while some other brands do the opposite. With max ISO 1600 and min shutter 1/125 for instance, the same light conditions will result in the M choosing 1/125 and ISO 400, while Fuji would choose 1/250 and ISO 800 instead. Giving priority to shutter speed would be a big plus e.g. for street photography. But so far, my M has always proved to keep it down at lowest speed 1/125 and favor ISO no matter what.
   
• Minimum shutter speed seems to be a misnomer as Leica will happily go below it without even warning you if proper exposure cannot be met in its limits. The underexposed red arrow does appear in the viewfinder but only when the meter is outside working range due to poor lighting conditions, unrelated to trespassing the shutter speed low limit.

In other words, maximum ISO is a hard limit but minimum shutter speed is not. This is what I think the M algorithm does:

1. | Set the shutter speed to Maximum Exposure Time from the menu. Calculate ISO required to achieve correct exposure at aperture set by user.

2. |==(correct exposure) => OK to take picture
3. |==(no ISO within range can give correct exposure) => calculate degraded shutter speed for maximum ISO. Go to 2.

TL;DR: in practice, the "maximum exposure time" menu setting is the base shutter speed that the camera will start from to calculate the ISO on a first attempt. But if the attempt is unsuccessful it will not hesitate to disregard that shutter speed setting and go slower.

Does this seem right or am I missing something? Is it the same in recent M iterations? I would be happy enough if the camera could at least display something when min shutter speed is slashed, but I don't see anything.

[jaapv]

I think that your question is answered in the posts above - and other threads.  Isn't the shutter time displayed in the viewfinder?