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How to use auto ISO?

Cirrus

By Cirrus
in Leica M8 / Leica M8.2

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Cirrus

Cirrus

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I have tried the auto ISO in the new firmware. In A mode it just seems all over the place and I can't see using it and I thought it would be best in manual mode anyway. In manual you could select an F stop and shutter and just have it fixed to these values you want. But the auto ISO here in manual mode jumps in full stops like 360 to 640. So this becomes a very gross way to control exposure. Am I missing something here?

Thanks,

Dan

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lars_bergquist

lars_bergquist

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No. Leica Camera AG missed it. The feature is useful only in a camera that runs exclusively in 'P-mode', i.e. with both aperture and shutter completely programmed and interdependent. That is, in a simple compact. Don't use the feature. If you need it, then a M8 is completely wasted.

 

The old man from the Age of Do It Yourself

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chris_livsey

chris_livsey

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I have tried the auto ISO in the new firmware. But the auto ISO here in manual mode jumps in full stops like 360 to 640. So this becomes a very gross way to control exposure. Am I missing something here?

Thanks,

Dan

 

No that's the way it works. If you set an aperture in manual, with fixed ISO, and then manually adjust exposure using marked speeds you change in "very gross" full stops. Setting speed instead you can set aperture more finely in half stops (or one thirds if you are fortunate enough to own a Zeiss-M lens :) )

I presume you want the auto iso to work like the shutter in auto where speeds smoothly change ?

It doesn't do this because obtaining intermediate ISO values means, usually in other cameras, a second amplifier in the circuit which introduces more noise. Or other workarounds which also reduce quality.

The combination of auto exposure " A " which smoothly changes exposure using the shutter and Auto ISO will give fine control as will Auto ISO and manual speed where you can finely control aperture manually. If you want to use a "fixed" aperture and manual speed you are not going to get fine control from the auto ~ISO.

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Shootist

Shootist

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No. Leica Camera AG missed it. The feature is useful only in a camera that runs exclusively in 'P-mode', i.e. with both aperture and shutter completely programmed and interdependent. That is, in a simple compact. Don't use the feature. If you need it, then a M8 is completely wasted.

 

The old man from the Age of Do It Yourself

Lars just where to you get that from? Or was that a joke. Auto ISO in a M is the best thing since they put a meter in it.

 

To Cirrus

If in A mode you find the ISO jumping way up and then down it could be you have the slowest shutter speed set to Lens Dependent or have it set to high, like 1/125. Also you can limit the highest ISO the camera uses. I have mine set to 1250.

I use Auto ISO all the time and find it a real boon. I have my slowest shutter speed set to 1/30 and use that for all lenses, even my 90mm Elmarit. When in A mode the sutter speed will drop below your lowest setting. The shutter speed setting is only a trigger to tell the camera to raise the ISO. Once you get to your highest set ISO the shutter speed will drop below your slowest set speed and the readout in the viewfinder will flash.

I don't find the ISO jumping all over the place but then like I said I have ISO high set to 1250 and lowest shutter speed set to 1/30.

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chris_livsey

chris_livsey

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Piero

 

Correct. There are no intermediate ISO values.

On A though you will get smooth transitions of exposure as the shutter, set on A, is able to make very small changes in speed to finely adjust the exposure.

 

For example this pm I took two shots one shows 1/750 the next 1/800 as I slightly changed framing, now that is fine tuning.

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gfspencer

gfspencer

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I'm confused. (I am often confused. :confused: ) So you set your shutter speed to A and your ISO to Auto ISO and pick you aperture? And let the camera select the ISO?

 

And how do you set up the Auto ISO? Do you select "Lens dependent" or do you specify a "Slowest speed" and a "Max ISO"?

 

And if you select Slowest speed and Max ISO what would the Slowest speed and MAX ISO be?

 

Sorry for all the questions but inquiring minds want to know. ;)

 

Thanks

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chris_livsey

chris_livsey

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So you set your shutter speed to A and your ISO to Auto ISO and pick you aperture? And let the camera select the ISO?

 

Yes, if Im happy the meter is going to be "correct". I would go manual if I was in any doubt.

 

And how do you set up the Auto ISO? Do you select "Lens dependent" or do you specify a "Slowest speed" and a "Max ISO"?

 

Lens dependant only sets the speed change point you can still select max ISO on that setting. I'm still experimenting with the possible combinations.

 

And if you select Slowest speed and Max ISO what would the Slowest speed and MAX ISO be?

 

That's like asking what aperture and shutter speed you set for 160 ISO :) It depends on what you are shooting. In motor sport you might want to set a min speed of 1/250 in a church it might be 1/15. I have been setting max ISO to 2500 as I would rather have a noisy shot than no shot at all.

 

Just have a play on something that doesn't matter that is one of the advantages of digital, cost free testing.

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chris_tribble

chris_tribble

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Hi - quick example (I'm stuck in a hotel room in Bucharest with nothing much else to do - so I was following this thread ...)

 

With the camera set to Auto ISO (1250 / 30th as limits) the first image can in as ISO 320 f2.8 @ 1/60th, the second - only shifting across so the main desklight wasn't in frame, came in ISO 1250 f2.8 @ 1/30th. If you're working in extreme ranges of light I think this is really helpful... and the noise levels in the 1250 shot are remarkably OK. I process in Lightroom - adding +15 luminance noise reduction was all that was needed.

 

I'm continuing to be impressed and know that I will use this a lot.

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Shootist

Shootist

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no idea what lens dependent does & I don't like things I don't understand.

 

You are not confused at all :D

 

The lens dependent setting let the camera (Leica) choose the lowest shutter speed to use as the trigger point to raise the ISO based on what lens you have attached to the camera, this is with coded lenses. With a none coded lens it seems the camera always chooses 1/60 as the slowest speed. I found that out becasue the hand coding on my CV 21/4 had worn off.

I just did a little test using a from a 21mm, after I re-coded it, to a 50mm lens and it seems the lowest shutter speed the camere will select is 1/45. That is with a 21mm lens attached.

For a 28 or 35 1/60 is the slowest and for the 50 1/90, although at times I got a flashing 1/90 shutter speed in the viewfinder and at other times I didn't. When the shutter speed LED's flash it is tell you the camera is at its highest ISO, that you set, and it is at or below the lowest speed for a shake free shot.

I won't be using lens dependent.

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rafael_macia

rafael_macia

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Please clarify for me;

 

Does the new software give a new choice in "ISO"? Auto or OFF?

 

With the new software can I just use "A", and have the ISO remain unchanged,, while the shutter changes ?

 

I have not upgraded the firmware.' and I use "A" but 95 % of my work is at 160 ISO

I don't want the ISO to be changing,

 

thanks

 

Rafael

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chris_tribble

chris_tribble

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ChrisL - I'm in Romania until Thursday - plenty enough Grouse for that...

Rafael - it's easy.

 

Use MENU to set up Auto ISO - here you can decide on the maximum ISO you want to use (I set 1250 as I really don't find a need for 2400 in most situations I shoot) + making your minimum shutter either dependent on the (coded) lens thats on the camera (remember 35mm = 1/35th second rule of thumb) or to a set value (I use 1/30th).

 

Use SET to determine if you're using AUTO ISO or a set value from 160 through to 2400. I have PRESET 1 = 160, RAW, 0 EV compensation / PRESET 2 = 320, RAW, 0 EV compensation, and now have PRESET 3 = Auto ISO, RAW, -1/3 EV compensation.

 

Works for me...

 

Hope that helps.

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