ISO 100, OMD-EM1II and firmware 3.0?

Started 2 months ago | Questions thread
bobn2 Forum Pro • Posts: 61,709
Re: ISO 100, OMD-EM1II and firmware 3.0?

Architeuthis wrote:

JaKing wrote:

Wolfgang, I only ever felt the need to use the extended LOW ISO with my E-30, not with either of my E-M1s (MkI or MkII).

With the E-30, which was a real noise machine given half a chance, using ISO 100 certainly lessened the noise. Never noticed any other changes for good or ill.

The main advantage is that you are getting a longer exposure on your sensor because the (nominal) ISO is lower. If you catch twice as many photons this way, the noise will be lower.

I suspect that using extended LOW settings with any camera that offers it/them is going to help with noise, but little else.

With the E-M1 MkII, using the lower extended settings keeps DR much the same, and that's a considerable improvement on previous sensors, most of which caused the DR to drop when using the extended setting (e.g. my E-M1 MkI). See Bill Claff's site for comparisons of whatever cameras you choose. It is here:,Olympus%20OM-D%20E-M1%20Mark%20II

This is very interesting, JaKing.

One must say, however, that the nominal ISOs that the camera manufacturers provide seem to be lies: DxO states that on the EM1II both nominal ISO64 as well as ISO200 correspond to real live ISO of 83. For EM1 nominal ISO100 and ISO200, the real live ISO is 122 in both cases:

Beware of those figures. What DxOmark calls 'measured ISO' isn't 'ISO'. For a start, it applies to the raw files, and ISO is very clear that 'ISO' does not apply to raw files. (it was always clear to those that understood the standard, but in the latest version, they have spelled it out explicitly, for those, like DxOmark, who were abusing the standard). DoO mark's measurement is still useful, just misnamed. What it tells you is what is the lowest ISO you could set your meter to (if you had a handheld meter separate from the camera) and still get raw files where the highlights weren't clipped.

When EM1 and EM1II real ISO vs. DR is compared, the performance of both cameras is pretty the same...

No 'real ISO'. That's a misunderstanding of what ISO is.

So what is the difference between extended ISO (I assume also the "new" ISO100 is extended ISO) and base ISO (both mean ISO83 (EM1II) or ISO122 (EM1), respectively)? Does the "new" ISO100 mean just another ISO83 setting?

They are all the ISO settings which they claim to be. The ISO 100 setting sets the meter and processes for 100 ISO. It has a more sensible amount of raw headroom than the old 200 ISO setting. I suspect that the other ISOs will also have less raw headroom, as they do on the EMIX.

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263, look deader.

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