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04-07-2010, 03:21 AM   #1
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Auto ISO in manual mode

I noticed that Auto ISO is disabled when shooting with manual lenses (K-x). I use Green button in Tv-shift mode for exposure.

I found this a bit strange, especially when camera is calculating shutter speed (when green button is pressed) and it also knows about the focal length, so I guess it should have been possible for it to select appropriate ISO if shutter speed is low enough, essentially auto ISO.

Any specific reason for this functionality to be missing in manual mode OR am I missing something?

Yusuf

04-07-2010, 03:37 AM   #2
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Basically because it is enabled with the addition of TAv on higher end bodies.
04-07-2010, 03:43 AM   #3
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QuoteOriginally posted by yusuf Quote
I noticed that Auto ISO is disabled when shooting with manual lenses (K-x). I use Green button in Tv-shift mode for exposure.

I found this a bit strange, especially when camera is calculating shutter speed (when green button is pressed) and it also knows about the focal length, so I guess it should have been possible for it to select appropriate ISO if shutter speed is low enough, essentially auto ISO.

Any specific reason for this functionality to be missing in manual mode OR am I missing something?

Yusuf
If you're selecting your aperture and the camera is calculating the shutter speed--which you can see before pulling the trigger and you can make your assessments--how would the camera know what you want?

That's the whole point of manual:

Should the camera give you 1/500 at 400 ASA? Or 1/250 at 200ASA?

It doesn't know whether you need or want the better 200 ISO, or the higher 1/500 speed.
04-07-2010, 03:45 AM   #4
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if the camera chooses ISO than it is by definition not manual

04-07-2010, 03:57 AM   #5
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QuoteOriginally posted by Pablom Quote
if the camera chooses ISO than it is by definition not manual
I respectfully disagree.

The point here is if green button has been used for calculating exposure, why not ISO was included in the calculation, just like in auto mode. It does not make sense logically to exclude this functionality when camera has all the necessary information.

Remember, I am NOT talking about complete manual metering, I am just using manual lens but putting exposure responsibility on camera (using green button).

Last edited by yusuf; 04-07-2010 at 04:08 AM.
04-07-2010, 04:02 AM   #6
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QuoteOriginally posted by Ira Quote
If you're selecting your aperture and the camera is calculating the shutter speed--which you can see before pulling the trigger and you can make your assessments--how would the camera know what you want?

That's the whole point of manual:

Should the camera give you 1/500 at 400 ASA? Or 1/250 at 200ASA?

It doesn't know whether you need or want the better 200 ISO, or the higher 1/500 speed.
Take it this way, I have a manual lens and all I am doing is to set aperture manually and telling camera to do the rest. Now, is there a reason for camera to treat exposure-on-demand (green button) differently than exposure with auto lenses?
04-07-2010, 04:03 AM   #7
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I don't know any other way, but it really isn't that hard. You just pick an iso you think will work (say 400) and then hit the green button. Once you see what the camera is giving you settings-wise you can decide to go up or down.

Shooting with manual lenses is a more time intensive, thought requiring process. It probably is closer to the way photography should be.
04-07-2010, 04:04 AM   #8
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QuoteOriginally posted by Rondec Quote
I don't know any other way, but it really isn't that hard. You just pick an iso you think will work (say 400) and then hit the green button. Once you see what the camera is giving you settings-wise you can decide to go up or down.

Shooting with manual lenses is a more time intensive, thought requiring process. It probably is closer to the way photography should be.
Agree, just wondering that when camera can do it why it is not doing. Similarly, exposure compensation. I always get 1 stop underexposer with my Tak 135mm and just wish I could set camera for +1 compensation.

04-07-2010, 05:28 AM   #9
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In order to respond fully, I will start by agreeing with Pablom and the others who maintain auto ISO defeats the purpose of manual.

However lets look further into the auto ISO function and its behavior and you will see why you don';t want it.

Auto ISO will always look for a solution by adapting ISO before changing anything else, therefore by pressing green button, if it were enabled it would raise the ISO to maximum (of the range set) and then adjust shutter speed up or down to get exposure. this means that you may as well just pick maximum SIO and shoot with it.

Additionally, in manual mode with flash, the camera is locked on maximum sync speed when focal length is not readable by the camera, therefore all flash shots with Auto ISO will be minimum power flash, with high iso.,

The net result in both flash and natural light is to shoot at the maximum ISO in the set range, therefore if you want this behavior, then just set the ISO to maximum, you don't need the auto function for that.

There is a mode called Tav where you can set shutter and aperture (assuming you really do know what you want for artistic reasons like controlled DOF and COntrolled motion blurr or freezing action) and then let the camera pick ISO, but I am not sure many people do this
04-07-2010, 05:38 AM   #10
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QuoteOriginally posted by Lowell Goudge Quote
In order to respond fully, I will start by agreeing with Pablom and the others who maintain auto ISO defeats the purpose of manual.

However lets look further into the auto ISO function and its behavior and you will see why you don';t want it.

Auto ISO will always look for a solution by adapting ISO before changing anything else, therefore by pressing green button, if it were enabled it would raise the ISO to maximum (of the range set) and then adjust shutter speed up or down to get exposure. this means that you may as well just pick maximum SIO and shoot with it.

Additionally, in manual mode with flash, the camera is locked on maximum sync speed when focal length is not readable by the camera, therefore all flash shots with Auto ISO will be minimum power flash, with high iso.,

The net result in both flash and natural light is to shoot at the maximum ISO in the set range, therefore if you want this behavior, then just set the ISO to maximum, you don't need the auto function for that.

There is a mode called Tav where you can set shutter and aperture (assuming you really do know what you want for artistic reasons like controlled DOF and COntrolled motion blurr or freezing action) and then let the camera pick ISO, but I am not sure many people do this
Max ISO is not a solution IMHO. The whole purpose of auto ISO is to use minimum ISO to get cleanest image with best shutter speed.

So say I am using 135mm, I would prefer that camera choses 1/500 @ISO 400 than either 1/100@ISO100 or 1/2000 @ISO1600. Certainly camera is capable of doing this math since it is doing it in case of auto lenses. It's just that it is crippling this functionality when using manual lenses.

I am not sure why we are comparing it with manual mode at all, it's green button and I am assigning the exposure responsibility to the camera - it's manual lens, does NOT mean manual exposure - exposure is still automatic.
04-07-2010, 05:43 AM   #11
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QuoteOriginally posted by yusuf Quote
Take it this way, I have a manual lens and all I am doing is to set aperture manually and telling camera to do the rest. Now, is there a reason for camera to treat exposure-on-demand (green button) differently than exposure with auto lenses?
You're getting into semantics:

Manually turning a dial to center a needle and pushing a button to do the same thing doesn't mean one is automatic and the other isn't. It is still manual.

And having the camera select your ISO is about as far away from manual as you can get.
04-07-2010, 05:51 AM   #12
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QuoteOriginally posted by Ira Quote
You're getting into semantics:

Manually turning a dial to center a needle and pushing a button to do the same thing doesn't mean one is automatic and the other isn't. It is still manual.

And having the camera select your ISO is about as far away from manual as you can get.
It's not semantics neither it manual And it certainly mean automatic because I am not doing any exposure setting myself. All, I am doing is to set aperture because camera can't do it. Now to use that manual lens, if I set dial to 'M' does not mean I am doing manual.

And, why wouldn't you don't like that functionality - any reasons? You have both the options - fix and auto iso, I would love to have it when I press green-button like in auto mode
04-07-2010, 06:10 AM   #13
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QuoteOriginally posted by yusuf Quote
Max ISO is not a solution IMHO. The whole purpose of auto ISO is to use minimum ISO to get cleanest image with best shutter speed.
define clean, best DOF, maximum sharpness, minimum grain, each of thse is a difrferent function and the camera is programmed one way at present, this does not mean I agree with the way it is programmed, just that it is what it is
QuoteQuote:
So say I am using 135mm, I would prefer that camera choses 1/500 @ISO 400 than either 1/100@ISO100 or 1/2000 @ISO1600. Certainly camera is capable of doing this math since it is doing it in case of auto lenses. It's just that it is crippling this functionality when using manual lenses.
so what you really want is an additional function or two, on the green button. the question is, how does the camera know what you want. 1/500 is not, on a 135mm lens a shutter speed that means anything. for hand holding w/o SR you need 1/200 therefore what does the camera take as the shutter speed criteria? In reality, the best "auto ISO function" you could ask for is that the camera leave shutter speed alone (assuming you set what you want) and then set ISO to match your selected shutter speed and aperture. The other possible would be to have optional program lines, use the input focal length and then sellect either landscape, normal or action lines to trade ISO and shutter speed again far from a manual mode
QuoteQuote:

I am not sure why we are comparing it with manual mode at all, it's green button and I am assigning the exposure responsibility to the camera - it's manual lens, does NOT mean manual exposure - exposure is still automatic.
Green button function, for other than manual aperture lenses does have multiple options, I think you just want one more, as described above. Also green button is not only used in manual mode, but can be used to reset the camera to the default program line in other modes, or set aperture or shutter to match the other you have selected (Hyper program mode)

Manual aperture lenses, are another story as green button is a semi automated stopped down metering mode, and nothing more
04-07-2010, 06:23 AM   #14
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I think the OP would want the green button in Hyper-manual with PK-m lenses mode to follow the same principle as the Av mode, where iso and speed are set following a set of rules.
Lowell, you nailed it with your second guess:

QuoteQuote:
The other possible would be to have optional program lines, use the input focal length and then sellect either landscape, normal or action lines to trade ISO and shutter speed again far from a manual mode
I find this very logical myself, but a little hard to be easily implemented, from the user point of view : where do you enable Auto-iso for green button in Hyper-manual???
If you use the standard ISO screen, it's a little misleading, as the iso is always manually set in HypM...
04-07-2010, 07:19 AM   #15
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QuoteOriginally posted by yusuf Quote
It's not semantics neither it manual And it certainly mean automatic because I am not doing any exposure setting myself. All, I am doing is to set aperture because camera can't do it. Now to use that manual lens, if I set dial to 'M' does not mean I am doing manual.

And, why wouldn't you don't like that functionality - any reasons? You have both the options - fix and auto iso, I would love to have it when I press green-button like in auto mode
In M(anual) mode, with or without a manual lens, pressing the Green button just stops down the lens (if possible) and takes an exposure reading. It's up to you to decide what to do with that reading. If you're in a hurry, go with it. If not, look at it and decide whether it's something you agree with, then adjust the settings accordingly. You could have pre-set the EV up or down to accommodate a specific lens to the reading. Looking at a reading and the subject, you can adjust the shutter and aperture for motion or backlighting or contrast or whatever, and adjust the ISO to suit your noise/detail comfort level. It's your call, not the camera's. That's why it's M(anual).

Using a manual lens (but not an A-type) when you want the camera to decide your ISO for you, just go to Av mode and set Auto-ISO. If you're not in a hurry, half-press the shutter and see what ISO it's chosen. If you're OK with that, shoot. If not, go back to M(anual) and set the exposure and ISO to your taste. YOU get to choose which decisions you want the camera to make. YOU get to decide whether to override its choices. Look at it this way: in any of the auto modes, you let the camera decide on the exposure, while you're busy composing and grabbing the image. In M(anual) mode, the camera advises you, but you make all the decisions yourself.
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