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02-25-2012, 09:27 PM   #1
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puzzled about auto sensitivity setting

I have just obtained my first auto lens for the K5 - I have been using a couple of old manual lenses up to now.

If I want to use say the auto lens in shutter priority mode, the book warns that the exposure may be incorrect if the sensitivity is not set to AUTO. However, the default e-dial functions for shutter priority mode do not include a means of setting sensitivity to AUTO, as the green button is inactive.

Is there some other way of doing it that I have not spotted in the book?? It would seem a bit silly for the default e-dial (including green button) function to be limiting in this sense.

The same issue arises in aperture priority mode, and a similar situation (not identical) in P mode.



02-25-2012, 09:40 PM   #2
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Press the ISO button and then the green button at the same time and your sensitivity will go into auto mode. This trick is probably hidden away somewhere in the manual

The only time you wouldn't achieve a proper exposure in shutter priority would be when your lens isn't fast enough to support the chosen shutter speed at that ISO, and this will be depicted in the VF by a flashing F stop value. Setting the ISO to auto would be the beginner's solution here- more experienced users would probably change either the shutter speed or both the ISO and the shutter speed to find an equillibrium.

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02-25-2012, 09:51 PM   #3
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In order for exposure be incorrect due to ISO not being set to AUTO in shutter priority, the camera would normally adjust your apperture value accordingly to achieve the correct exposure, so only in the case that the maximun or minimun aperture setting is not sufficient to ensure correct exposure, you would have problems, then you could manually set ISO higher or lower. In any case to activate the auto ISO just hold the ISO button and then press the green button. To disable it hold the ISO button and turn the rear e-dial. This works in all modes except Sv because obviously your supposed to set the ISO manually and the TAv because the camera needs to set ISO automatically.
02-25-2012, 10:20 PM   #4
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Thanks for the advice

Thanks both for your advice - doubly valuable, because it also explains that the 'incorrectness' is not so much a possible camera error (i.e. sensitivity must be set to auto to expose correctly in these modes - which was my first interpretation of the note in the book) as 'unable to achieve correct exposure because the user's selected iso & shutter speed in combination with that lens's max aperture does not allow it'.




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