ISO 100, OMD-EM1II and firmware 3.0?

Started 2 months ago | Questions thread
bobn2 Forum Pro • Posts: 61,728
Re: Meaning of base vs. extended ISO

katastrofa wrote:

bobn2 wrote:

Chris Noble wrote:

bobn2 wrote:

Chris Noble wrote:

Architeuthis wrote:

I have installed firmware 3.0 on my OMD-EM1II.

I wonder, whether the new ISO 100 brings better dynamic range, less noise and better colors compared to the base ISO 200, when used for raw files?

Already in earlier firmware versions ISO 64 was available, but as far as I understand it, this does not improve DR, noise or color, but is useful only when too much light is present, to maintain wide aperture and increase exposure time...


Base is the lowest analog gain before A/D conversion. It's the lowest noise setting.

Extended (top and bottom of the range) is digital manipulation. No SNR improvement. And only useful for shooting JPEGs.

These definitions do not always work.

What kind of work are you referring to? They are definitions.

They don't work when it comes to sensibly delineating 'base' or 'extended

In any case, what you're calling 'base' is not the lowest noise setting. It's generally the highest noise setting so far as electronic noise goes.

Lowest gain = lowest noise introduced by the electronic processing.

Incorrect. It confirms my impression that you're working on the very common but completely nonsense accounts of what ISO is, what it works and what is the significance and effect of 'gain'.

So far as the shot noise goes, any increase in exposure will lower it, so the (so called 'extended') settings below will give less noise.

You are confusing noise due to the particle nature of light (shot noise), which the camera electronics can't do anything about, with the noise introduced by the camera electronics, which is what base ISO refers to.

I'm confusing nothing. I'm separating the two, which you failed to do, for the sake of clarity. With respect to the noise introduced by the camera electronics (or read noise) that reduces as ISO is increased, in general.

My photos look more noisy when I increase the ISO. Why?

Changing the ISO sets the meter so that you choose to use a lower exposure. Lower exposure means less light energy. Less light energy means fewer photons captured in the image. The signal to noise ratio in the image goes as the square root of the number of photons, so if you capture fewer, you get a lower SNR, which you say is 'more noisy'.

-- hide signature --

263, look deader.

Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow