What is "image quality" anyway?

JimPearce wrote:

I'm really getting sick of this "term of art". If it has something to do with quality images, well I know them when I see them. Subjective factors like composition, the light on the subject, critical focus, bokeh, foreground/background separation, vivid colour etc. are critical. On the other hand, if it were something objective like DR at ISO, colour depth at ISO etc. it would be measurable. As it is it is something undefined which is piled on top - an undefined sum of unspecified characteristics - and smacks of confirmation bias to me. "Oh yes, I had to go FX because it slaughters DX on image quality.". I'm beginning to associate IQ with low IQ. End rant.

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Jim