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StephenL
15th September 2009, 03:20 PM
There has been quite a bit of discussion in the photo press and fora regarding the "base" level ISO for the sensor in the E-620. Although not documented by Olympus, it seems generally accepted that although the lowest ISO setting is 100, the "best" base setting, ie the level at which the optimum definition is available, is ISO200.

Now, I've been playing with the Auto ISO setting on my E-620, and have discovered that, whilst you can set the maximum ISO setting to anything you want, the base ISO setting is 200, and not the 100 which is the absolute minimum.

This seems to reinforce the opinion that ISO100 is an artificial low setting, and the true base level of the sensor is indeed 200.

Or have I missed something?

Ian
15th September 2009, 03:50 PM
There has been quite a bit of discussion in the photo press and fora regarding the "base" level ISO for the sensor in the E-620. Although not documented by Olympus, it seems generally accepted that although the lowest ISO setting is 100, the "best" base setting, ie the level at which the optimum definition is available, is ISO200.

Now, I've been playing with the Auto ISO setting on my E-620, and have discovered that, whilst you can set the maximum ISO setting to anything you want, the base ISO setting is 200, and not the 100 which is the absolute minimum.

This seems to reinforce the opinion that ISO100 is an artificial low setting, and the true base level of the sensor is indeed 200.

Or have I missed something?

This is something I am in quandary about. I must confess I haven't seen any definitive evidence in my photography that has made me avoid ISO 100, but then I haven't yet done an exhaustive test. Also, the dxoMark (http://dxomark.com/index.php/eng/Image-Quality-Database/Compare-cameras/(appareil1)/315%7C0/(appareil2)/220%7C0/(onglet)/0/(brand)/Olympus/(brand2)/Olympus) RAW file analysis of Olympus and Panasonic system cameras, doesn't show any issues with ISO 100 compared to 200.

Ian

stevednp3
15th September 2009, 05:10 PM
The E-30 is the same and has the lowest auto setting of 200, I always wondered why I couldnt select 100 as my minimum

oly_om
15th September 2009, 06:40 PM
DPreview have tests that measure the DR at various ISO settings. What becomes very clear is ISO 200 has more DR than ISO 100. Given that it isn't a whole stop worse at ISO 100 (E-30 is about 1.1 EV worse, E-3 is about 0.1 EV worse in the highlight range), that would indicate that ISO 100 is not simply ISO 200 over-exposed and clipped back... What it does say is perhaps with the E-30, the base sensor sensitivity may be a little over ISO 200 and for the E-3, it's a little over ISO 100. On the E-3, you can configure your lowest setting to be ISO 100.

Andy

Edit: Just looked at their test of the E-P1 - that would indicate the base sensitivity is a bit below ISO 200 - which is welcome as there isn't much point for having the lower ISOs otherwise!