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Auto ISO or Not?

sathlersathler Member
edited February 2014 in Nikon
Could I get some of our members here to give their thoughts on the benefits or the negatives of using Auto ISO?
I bought recently the Nikon D4 and most of my photos are portraits outdoors with natural light with fill flash.

Regarding the Minimum Shutter Speed would be better to set it to AUTO or set my own?

The reason for my question is that I use the heavy Nikon 70-200mm 2.8 VR Lens and to make sure that I get best results hand held I normally,more or less, double the shutter speed in relation to the size of the lens…In this case of the 200mm nikon lens I normaly set the minimum shutter speed to 1/500th. But have been thinking if the AUTO minimum shutter speed would bring more benefits?

Thank you!



  • You can set the camera to manual so that you can set the shutter speed and aperture yourself and then, with auto ISO, let the camera select the appropriate ISO.

  • I see a few questions in there.

    First, on auto ISO - I like it in some situations, but using flash is definitely not one of them. Without flash, I sometimes use auto ISO when dealing with quickly changing lighting conditions. As johnmottershaw above points out, it works great in manual too - you just turn on auto ISO (minimum shutter speed setting won't come into play) and you set the shutter and aperture, and the camera will select the ISO for the correct exposure based on the metering.

    On using auto ISO with flash - I don't like it. It does weird things that I haven't figured out yet. For example, it seems to love ISO 400 for some reason. With flash, I prefer to be more deliberate in what my ambient exposure will look like (selecting shutter, aperture, and ISO myself), then let TTL flash expose the subject. If you turn on auto ISO, you basically lose control over your ambient exposure.

    On auto ISO and minimum shutter speed, I've used the AUTO shutter speed setting successfully. If you're using the 70-200 you could say give me a shutter speed no less than 2X the focal length and it will go from 1/140 to 1/400 as you zoom - if that works for your situation, go for it. Note the minimum shutter speed setting only comes into play shooting in P or A mode. The rub here is if you're using flash and auto ISO settings like these. As soon as you go above the sync speed of the camera (1/250 or 1/320 if you have enabled that), then you're getting into high speed sync territory (Auto FP) and the effectiveness of the flash output is suddenly going to change very dramatically. And not in a good way, haha.

    You should not need to shoot that fast with the 70-200 - the VR is very effective on it and you should easily be able to get consistently sharp shots at 1/250 or slower at 200mm.

    Hope this helps.
  • sathlersathler Member
    edited February 2014
    Hi Nikonguy,

    Thank you so much for your help here.

    By the way...are you the same "That Nikon Guy" (from YouTube) from NSW Australia?
  • I agree about its use with flash - I definitely switch it off then.
  • Sathler, no relation to him. :)
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