Auto ISO to obtain correct exposure?

[lct]

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No need to chimp with non Leica auto iso. One just has to turn the shutter speed dial that's all.

[Jeff S]

I seem to have stirred up a hornets nest.

 

No, just another similar 40 or so additional posts.

 

The forum lacks an automatic mechanism for limiting redundancy. Perhaps we need a forumware update.

 

Jeff

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[bephoto]

Yes - you have missed 12.387 posts on the subject

 

ROTFLMAO

[mjh]

From your description it seems what you want here is not auto ISO but rather a minimum shutter speed. If you use auto ISO to ensure that the shutter speed doesn't drop below a certain value you will still get "watered-down beer".

Yes indeed, but at least it is for a good reason (avoiding slow shutter speeds). Still it would preferable if the camera did refrain from increasing amplification above ISO 800, 1600, or thereabouts and would leave it to the raw converter to brighten the image. Fuji’s X models do that for any ISO values > 1600 so the raw data of shots at ISO 1600, 3200, or 6400 are identical; only the meta data differs.

 

If you think auto ISO is a bad idea: don't use it. What's so hard about that?

It encourages using the camera in a way that yields suboptimal results. I have no difficulty avoiding the Auto ISO trap but this isn’t about me. In an ideal world every photographer would understand what happens when you change the ISO setting of a digital camera and how this affects the pictures shot, but we are still quite far from that ideal.

[lct]

Horses for courses. Just tried auto iso in manual mode with Fuji X-E2 and CV 21/4. Handy feature indeed. No need to chimp and no risk that the camera selects a slower shutter speed as does the M240. Just turn the shutter speed dial and let the camera select iso automatically. 1600 iso here (f/4, 1/30s, 8 MB file).

[rafikiphoto]

Horses for courses. Just tried auto iso in manual mode with Fuji X-E2 and CV 21/4. Handy feature indeed. No need to chimp and no risk that the camera selects a slower shutter speed as does the M240. Just turn the shutter speed dial and let the camera select iso automatically. 1600 iso here (f/4, 1/30s, 8 MB file).

 

Too true. I am just selling all my X stuff but I'm keeping the X-E2 for the very low-light occasions. The Metabones converter is a great accessory so I can use all my M glass.

[rafikiphoto]

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Thanks for the FW update Leica. This function works a treat.

[paulsydaus]

Please explain why these people are misguided exactly?

Edit: I read your explanation.

Will respond later

 

While many people seem to be lusting after this feature I still think it is ultimately misguided. But as nobody cares what I think you may still get your way.

Edited June 30, 2014 by paulsydaus
update

[mjh]

Please explain why these people are misguided exactly?

I already did, in this thread and elsewhere.

[paulsydaus]

I already did, in this thread and elsewhere.

 

 

I will respond tomorrow. In general I would say that calling people misguided on this matter is a whee bit arrogant don't you think?

[digitalfx]

Auto ISO is simply a way of achieving correct exposure when you need the shutter speed and aperture to remain constant, such as to stop movement and give enough DOF etc. What can be wrong with that?

 

Steve

 

I think its just a fundamental difference in they way Leica cameras work vs others. Are we next going to ask for a P mode?

[250swb]

I think its just a fundamental difference in they way Leica cameras work vs others. Are we next going to ask for a P mode?

 

What on earth leads you to that conclusion?

 

Auto ISO in Manual mode is simply a very effective extra tool to get the correct exposure when technical circumstances dictate it. What it isn't is a fetishistic desire to put optimal image quality above the quality of the photograph. Yes there will be some more noise some of the time, and yes it works like other camera's implement it, big deal. I know some people's approach to Leica's start with the premise of 'I spent all this money, so why would I degrade image quality by allowing the camera to choose the ISO'. But there are still enough 'misguided' traditionalists who think a bit of noise or grain in the image comes second to the ability to photographing something interesting in the first place.

 

 

Steve

[digitalfx]

What on earth leads you to that conclusion?

 

I know some people's approach to Leica's start with the premise of 'I spent all this money, so why would I degrade image quality by allowing the camera to choose the ISO'. But there are still enough 'misguided' traditionalists who think a bit of noise or grain in the image comes second to the ability to photographing something interesting in the first place.

 

 

Steve

 

First, this has nothing to do with how much money one spent. I will say I misread your request though please ignore my comment. Personally I don't find a use for this feature, but I can see now how some might find it useful. I find the current auto iso implementation more than adequate. I use full manual to accomplish what you want just as quickly.

Edited July 1, 2014 by digitalfx

[lct]

Well-guided people are those who prefer blurred 200 iso pics at 1/15s or dark ones at 1/125s instead of well exposed 1600's at 1/125s i guess.

Motion blur amateurs or nyctalope photogs sort of.

[bocaburger]

One of the advantages of digital is having ISO as a third exposure parameter, mitigating the inverse nature of shutterspeed and aperture. However I would prefer in manual mode simply to have ISO assigned to the thumb wheel and affecting the metering diodes just like changing shutterspeed does.

[Son of Helm]

Well-guided people are those who prefer blurred 200 iso pics at 1/15s or dark ones at 1/125s instead of well exposed 1600's at 1/125s i guess.

Motion blur amateurs or nyctalope photogs sort of.

 

Some of those 'well-guided people' may prefer not to have auto-iso on permanently. Then fiddling with turning it on when needed may waste time. Those 'well-guided people' may prefer

some dark pictures at ISO 200, later to be corrected in LR with the same result as shooting it at 1600. Resulting noise level is the same as aperture and time settings are unchanged.

Usually after a few such shots there is time enough for dial in ISO 1600 so one can view the shots in-camera on location.

[jonoslack]

Hi There

I'm going to pick you up on this one. Of course, the discussion is now moot in that we have TAV mode with the new firmware. It always seemed strange to me that you (and several others) feel that an option should be denied to those who DO want it on doctrinaire grounds -but that's not the point either

 

 

With aperture priority the camera takes care of an optimum exposure: you choose an aperture and the camera determines a shutter speed that ensures enough light reaches the sensor. How much light needs to be gathered during the exposure is determined by the ISO setting.

 

Now when the aperture chosen is small and/or there isn’t much available light to begin with, a shutter speed compensating for the lack of light would get so slow that you cannot shoot handheld, and that is the raison d’être for Auto ISO: When the shutter speed would need to go below a selectable minimum speed the camera would rather increase the ISO setting; only when the ISO value hits a selectable maximum value would the camera use a slower shutter speed. So the reason to use Auto ISO is to prevent the camera from choosing slow shutter speeds.

 

In manual mode this isn’t an issue at all since the shutter speed is selected by the photographer. At a given ISO setting, of all the selectable combinations of aperture and shutter speed only a small subset guarantees an optimum exposure, all the others resulting in either over- or underexposure. Now the idea is that with Auto ISO in manual mode one could turn manual mode into another automatic mode: whenever the chosen aperture and shutter speed values would result in underexposure, Auto ISO increases the ISO value and amplifies the weak sensor signals so the image doesn’t look underexposed. Unfortunately this doesn’t work for overexposure which still needs to be avoided.

 

So whereas in aperture priority mode the camera controls the exposure by varying the exposure time and Auto ISO merely serves to prevent the choice of slow shutter speeds, in manual mode there is no actual automatic exposure at all – it is the photographer controlling how much light hits the sensor – and Auto ISO serves to hide the effects of underexposure if it occurs. (Suppose you go to a pub and order a pint of lager, and the landlord only draws as much beer as he thinks he can spare, filling up with enough water so he can sell you a pint. Anyone who is fine with that should go ahead and request Auto ISO in manual mode.)

 

Rather than arguing the toss with you about the philosophy of this, let's think of it in practical situations.

 

For instance you are shooting a concert, where the light is changing all the time, and where the subjects are moving around. You might decide (depending on the lens) that the longest exposure you can deal with satisfactorily is 1/60th - and that you need an aperture of at least f4 to have a decent chance of getting things in focus. You'd like to have the lowest ISO value to ensure good quality pictures. Now is your moment - do the settings - you have Auto ISO functioning, so you'll get the lowest possible ISO with your settings of 1/60th and f4.

 

You can't do this in Aperture priority - even if you set the longest shutter speed to 1/60th, the camera will still give you sliding values for ISO and shutter speed.

 

You don't have a chance in manual mode with the light changing so fast.

 

For Instance - you're being driven through spectacular countryside in China, wonderful scene after wonderful scene passes you by. You need a shutter speed of at least 1/1000 with your 50mm lens to have a chance of a sharp photo, and things are happening so fast that you're better off with f5.6 at least . . . . . . . you just make sure that your manual setting ensures that you will get no overexposure, and using Auto ISO with 1/1000 at f5.6 will give you properly exposed photographs all the time. Once again, it's a difficult situation to use with Aperture Priority - and impossible in manual mode.

 

 

Michael, at the top of your post you say:

 

It should be noted that Auto ISO in manual mode is something quite different from Auto ISO in aperture priority mode in that it serves a different purpose.

 

In these cases clearly not - the difference is that as a photographer you have less control of the situation in Aperture Priority mode in that the shutter speed is also going to be outside your control. I would contend that Auto ISO in manual mode can be a really invaluable tool in serious shooting conditions - denying it is particularly pointless in that if you don't like it - just switch it off (or select a manual ISO!).

 

Of course - as you point out - Auto ISO in manual mode doesn't protect you from overexposure . . . but in Aperture Priority mode it doesn't really protect you from too slow a shutter speed (if you've chosen too small an aperture). . . . unless you've picked a minimum shutter speed - in which case it doesn't protect you from underexposure either! It's not a distinctive difference in function.

 

I think the point is that you hadn't considered manual mode as a device for setting minimum possible parameters to get sharp pictures - you were considering it as a way for the photographer to choose a manual exposure (in which case Auto ISO is clearly not wanted - but can easily be turned off).

 

Having been involved in the history of this I understand that Auto ISO in manual mode in the M9 was actually accidental rather than intentional, and due to remonstrations from some users with your point of view it was turned off intentionally in the M240 (of course, the users, like me, who really appreciated it in the M9 didn't bother to write to Leica saying that we did).

 

For me it's the best improvement in the M240 software update - invaluable in a lot of marginal situations where both the aperture and the shutter speed are critical to the situation. Setting a minimum shutter speed in Aperture priority doesn't do the same thing at all, and there is no other way to deal with such situations.

 

There are other times when I want to shoot the M240 just like my M6 - in which case I will actually set the ISO I want (rather than letting the camera use the last picked). Horses for courses indeed.

[jonoslack]

Some of those 'well-guided people' may prefer not to have auto-iso on permanently. Then fiddling with turning it on when needed may waste time. Those 'well-guided people' may prefer

some dark pictures at ISO 200, later to be corrected in LR with the same result as shooting it at 1600. Resulting noise level is the same as aperture and time settings are unchanged.

Usually after a few such shots there is time enough for dial in ISO 1600 so one can view the shots in-camera on location.

 

Well, I quite agree with you - there are different situations which call for different solutions, and now there is the opportunity to decide whether you do want Auto ISO in manual mode, or if you don't. If you don't then you have no changes to make, and the camera will operate just as it did before - but if you DO, you now have the option to do so.

 

Clearly the option was needed!

[lct]

[...] Those 'well-guided people' may prefer some dark pictures at ISO 200 [...]

They must be well-guided by a radar then . Just kidding .

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[MarkP]

Auto ISO in Manual mode is an excellent feature for exactly where control of shutter speed and aperture take priority over ISO-determined IQ.

 

As Jono explained there are times where this feature will be invaluable and Im looking forwards to when I can next use this feature which significantly enhances the camera's functionality.