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Base ISO 200 and Low ISO (100) compared

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  • Base ISO 200 and Low ISO (100) compared

    After doing a low ISO exposure bracket with the E-P5 for Ulfric the other day, here are two shots (both RAW+JPEG) taken at ISO 200 (base ISO) and Low ISO (100). The Zip download link is here:

    I'd be very interested to know what everyone here thinks of these two results.

    By the way, centre-weighted metering was used, @f/1.8, 75mm m.Zuiko, tripod was used and IS was switched off.

    It seems to me that if we are happy to expect diminishing image quality when ISO sensitivity rises, why shouldn't we be content for this to happen as ISO reduces below base ISO? In which case, we should be offered the option of several ISO steps below base ISO in our cameras.

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  • #2
    Re: Base ISO 200 and Low ISO (100) compared

    Thanks foir posting these, Ian. To be honest I only checked the JPEGs but even highly magnified on my screen I could not tell the difference. You make a good point about whether we would be willing to trade ultimate quality to get ISO several stops lower than base, in the same way that we accept image quality will deteriorate at higher ISO. Personally speaking I would welcome that. In bright light ISO 200 can be a real pain, especially when wanting to use fast aperture lenses wide open. I know that ND filters can be fitted but this is hardly convenient and may slightly compromise image quality anyway. I find ISO 1600 more than acceptable on the E-M5, so ISO 25 (3 stops below base) would be welcome.

    "A hundredth of a second here, a hundredth of a second there � even if you put them end to end, they still only add up to one, two, perhaps three seconds, snatched from eternity." ~ Robert Doisneau


    • #3
      Re: Base ISO 200 and Low ISO (100) compared

      sounds reasonable to me
      Cameras: E-M5, E-PM2, OM40, OM4Ti
      Lenses (M.Zuiko Digital): 7-14mm/F2.8, 12-40mm/F2.8, 40-150mm/F2.8+TC1.4x, 12-50mm/F3.5-6.3, 14-42mm/F3.5-5.6 EZ, M.ZD 40-150 F4-5.6 R, 75-300mm/F4.8-6.7 Mk1, 12mm/F2, 17mm/F1.8
      Lenses (OM Zuiko): 50mm/F1.2, 24mm/F2, 35mm/F2.8 shift
      Lenses (OM Fit): Vivitar Series II 28-105mm/F2.8-3.8, Sigma 21-35mm/F3.4-4.2, Sigma 35-70mm/F2.8-4, Sigma 75-200mm/F2.8-3.5, Vivitar Series II 100-500mm/F5.6-8.0, Centon 500mm/F8 Mirror
      Learn something new every day