non-standard ISOs increase noise?

Discussion in 'Open Discussion' started by barry13, Jun 7, 2014.

  1. barry13

    barry13 Super Moderator

    Mar 7, 2014
    Southern California
    Real Name:
    Hi, I came across an article today ( which says:

    Does this apply to any/all mu-43 cameras?

    I notice on my E-M1 (fw 1.4) that if I change the "ISO Step" option to '1 EV', then it only offers the 'standard' ISOs when choosing manually, but if ISO is set to Auto, it'll still choose non-standard ISOs such as 640.

  2. Robstar1963

    Robstar1963 Mu-43 Top Veteran

    Jun 10, 2011
    Isle of Wight England UK
    Real Name:
    Robert (Rob)
    I think the 'low' ISO setting made available on latest firmware on OM- D EM-5s (and also as standard on EM-1s ?) is equivalent to 100 ISO but is I believe artificially generated by the camera and is only a 'pseudo' 100 ISO and apparently subject to a lower dynamic range
    I don't know if there is any effect on image noise on this setting ?
  3. biomed

    biomed Mu-43 Hall of Famer

    Aug 22, 2013
    Seattle area
    Real Name:
    Panasonic does the same with the "low" ISO setting. I haven't seen any advantage to using this over the normal Low ISO setting of 200. I believe you are correct about the lower dynamic range.
  4. b_rubenstein

    b_rubenstein Mu-43 All-Pro

    Mar 20, 2012
    Melbourne, FL
    From what I read several years ago, Canon did what was described in your quote. No idea if other makers used the same technique.

    FWIW, Kent DuFault (the person who was quoted) based on what I read on his site is just a photographer and not particularly technical. Professional photographers virtually never have a solid technical background.
  5. Luckypenguin

    Luckypenguin .

    Oct 9, 2010
    Brisbane, Australia
    Real Name:
    Rather than me make a poor attempt to try to explain the concept here, if you research the term "ISO-less sensor" you will find that for cameras which use type of sensor, every ISO other than the base value requires a push to the exposure so there is no great distinction between, say, a 2 stop push and a 1 2/3 stop push. Sensors such those made by Canon don't use this type of design and I do remember watching a demonstration a few years ago that showed how the "uneven" ISO values could produce more noise than the "even" values.
  6. metalmania

    metalmania Mu-43 Veteran

    Jul 19, 2012
    Canon 5D Mark II prefers ISO 160, 320, and etc..

    Sent from my Nexus7 using Tapatalk 2
  7. fortwodriver

    fortwodriver Mu-43 Top Veteran

    Nov 15, 2013
    Toronto, Ontario, Canada
    Real Name:
    Um...this was a Canon thing... I don't think it applies to m43... I remember this mostly coming about around the time of the Canon 7D and the 5D mkii in 2009. I remember people making WAY too much of a big deal about it.
  8. MajorMagee

    MajorMagee Mu-43 All-Pro

    Feb 24, 2011
    Dayton, OH
    It was years ago that I tested it on an E-PL2, but I couldn't see that it mattered on that sensor.
  9. barry13

    barry13 Super Moderator

    Mar 7, 2014
    Southern California
    Real Name:
    Thanks for all the answers!


    Sent from my iPad using Mu-43