Dynamic Range -- what it is, what it's good for, and how much you 'need'

Started Oct 17, 2011 | Discussions thread
Rriley Forum Pro • Posts: 21,846
Re: Badge of honor.

Great Bustard wrote:

Rriley wrote:

I've been busy working on the discrepency between DxOMark's DR measure and Imatest's. As it turns out, DxOMark measures what DR is defined to be, and what I've said all along, whereas Imatest measures the DR of a processed photo:

you knew NOTHING about it
you had to ask for help on it
you were clueless as to what was going on and this is more pretence

I knew nothing about Imatest, I asked, I got the answer. And when I don't know something, I ask, unlike parading around like a complete effing idiot like you and your fellow entertainers.

Case in point:


Yes, that's basically correct, although Imatest has an additional problem (at least in the versions I have seen) where it does not properly compensate for the the clipping of the negative going noise excursions as the grey patches approach black, which I cover in another post. This, as much as anything, is likely why Imatest measures higher DR than what DxOMark does.

the most suitable counterpoint was posted by me first up

but I think DXO uses what I'd call an "engineering" based approach where DR is counted up to the point where you can't distinguish any signal at all. In practice, that overstates useful or practical DR significantly. A better approach is to establish some noise threshold as the cutoff point. The problem with that, is that some images will make noise more or less noticable and some viewers are more or less tolerant of noise. So you really need a range of thresholds. I like that Imatest delivers its results in that manner. There's a very good chance that "one number" DR numbers aren't saying what the reader thinks. Any time you see such single numbers, make sure you understand what the number means before placing too much importance on it

which pretty well laid it all out from the beginning
so you were saying ?

i knew enough to ask the question

But I knew enough to get the answer. Now, do you know enough to get understand the answer?


Well? Do you?

like I said, Jay covered that from the beginning

the 'fool' here didnt even think to ask it

Because I did not know that Imatest gave different results than DxOMark.

and somehow you think that puts you in front

Yes -- in fact it does.


And yet, I was right all along, whereas you were just fishing for some way to discredit DxOMark, and show the fool once again.

i think DxO is roundly criticised for its 'individual' even cavalier approach. More importantly is how DxO is used to bash, you would know more about how that works than I

It's one thing to be ignorant -- I was ignorant about Imatest, and am getting an education in the link above. It's quite another to parade your ignorance as a badge of honor, but, well, that's what makes The Entertainers' posts so entertaining, I suppose.

Yeah -- that.

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