Floating ISO

[Guest NEIL-D-WILLIAMS]

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What is it??

 

 

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[jaapv]

ISO is automatically adjusted to the effective aperture of the focal length set on a zoom lens with variable  aperture.

[Guest NEIL-D-WILLIAMS]

ISO is automatically adjusted to the effective aperture of the focal length set on a zoom lens with variable aperture.

thanks Jaspv......... so with me using M lenses no need to worry about it right??

 

 

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[FlashGordonPhotography]

It's a pain in the arse that I can't turn off. That's what it is.

 

Gordon

[LD_50]

There is a menu function under Auto ISO settings to turn it off and on.

[FlashGordonPhotography]

Thanks!!

 

I hardly ever use auto ISO so I didn't think to look there for a setting that affects me when I'm setting my ISO manually.

 

Gordon

[Likaleica]

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thanks Jaspv......... so with me using M lenses no need to worry about it right??

 

 

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No, Neil.  It floats with M lenses, too.  Useful when you'd rather let ISO wander rather than aperture or shutter speed.

[Joakim]

No, Neil.  It floats with M lenses, too.  Useful when you'd rather let ISO wander rather than aperture or shutter speed.

Hi

 

Now I am curious but isn't this Auto ISO your talking about? It was my understanding that ISO floated with the effective focal length so how can it then change with a prime lens?

[jaapv]

No, Neil.  It floats with M lenses, too.  Useful when you'd rather let ISO wander rather than aperture or shutter speed.

I don't think you have this right. Floating ISO is for zoom lenses with variable aperture. M lenses do not fall into this category, but can be used with Auto-ISO, which is something different. (albeit subtly so).

[steppenw0lf]

Now I am getting interested: What happens if I choose to set in the AutoISO settings the floatingISO to off ?

For the SL zooms ?      For the SL primes ?     For manual primes ? (M or R)     For R zooms ?    For other adapted lenses not recognized by the original adapters ?

[jrp]

http://www.l-camera-forum.com/topic/258176-floating-iso

 

The manual reads as if it has been put through google translate and back a few times.

 

If you are using manual mode with a variable aperture zoom, and Floating ISO is on, then changing the zoom (and so aperture) will alter the ISO to maintain constant shutter speed (I think).

[jaapv]

http://www.l-camera-forum.com/topic/258176-floating-iso/

 

(repeated for convenience)

 

 

Maybe I should merge the threads, or would that throw everybody into more utter confusion? (if that is possible )

[Bill W]

I will keep setting iso manually.....!

[steppenw0lf]

After reading the other thread my conclusion is: I will probably never benefit from this option. (But I leave it always on, as I see no bad effects).

Too bad, I could have found it useful with some R zooms. 

I never use the SL zooms in M mode - so I will never encounter a case where this jumps in.

(I hope these are the correct logical conclusions     )

[ramarren]

The SL's Floating ISO function is a limited use function specifically designed to allow consistent manual exposure at maximum aperture with fixed ISO settings when using SL-dedicated lenses that have a variable maximum aperture. It allows the ISO setting to 'float' upwards by one stop to accommodate the change in maximum aperture without changing the set shutter time and aperture value. It simply makes your exposures more consistent—a one stop rise in ISO hardly even noticeable unless you're already up near the top of the ISO range, but a one stop change in aperture or shutter time could be very noticeable if you're doing critical work. 

 

There is no other time that it is useful or operational. It is an example of Leica paying attention to a small operational detail that will only affect a very limited number of uses. 

[Bill W]

If I can find it, I will turn it on I guess. The lens I will use the most is the 24-90 SL

[Guest NEIL-D-WILLIAMS]

If I can find it, I will turn it on I guess. The lens I will use the most is the 24-90 SL

i just turned mine off.......... trying to save some battery power

[LD_50]

If I can find it, I will turn it on I guess. The lens I will use the most is the 24-90 SL

It's easy to find. Auto ISO settings. Floating ISO. Owner's manual spells it out.

[Likaleica]

Thanks to Godfrey for the great explanation.  I find it a little frustrating when I'm in Aperture Priority, which is my most common exposure mode.  I think the Auto ISO floats to keep the exposure at the maximum time interval as defined by 1/focal length.  There are times when I want to keep a fast shutter speed, for example to freeze a moving animal, but the camera chooses instead to drive the ISO down.  I know I can just remove the camera from my face and make adjustments in the menus.  It gets messy with two variables.  Kind of like shooting in Program Mode.  

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[LD_50]

Thanks to Godfrey for the great explanation. I find it a little frustrating when I'm in Aperture Priority, which is my most common exposure mode. I think the Auto ISO floats to keep the exposure at the maximum time interval as defined by 1/focal length. There are times when I want to keep a fast shutter speed, for example to freeze a moving animal, but the camera chooses instead to drive the ISO down. I know I can just remove the camera from my face and make adjustments in the menus. It gets messy with two variables. Kind of like shooting in Program Mode.

Auto ISO has settings for 1/f or 1/(2f) to manage what you're asking for. If you're trying to keep a fast shutter speed and still want Auto-ISO and choice of aperture, why not use the 1/(2f) choice or just go to Manual mode with Auto ISO?

 

Floating ISO option seems to still be confusing people here. It only affects variable aperture zooms native to the SL if you're changing focal length and are wide open so the aperture is changing with your focal length change. What you're describing is not a Floating ISO concern, but instead a basic Auto-ISO and exposure choice concern that would be inherent with all lenses.