DxOMark's measured ISOs vs. manufacturer ISOs

Started Mar 13, 2013 | Discussions thread
texinwien Veteran Member • Posts: 3,326
Re: No Sarcasm

Jack Hogan wrote:

texinwien wrote:I do understand that, Jack. I think the difficult thing for the DPReview guys is that this topic has been hashed and rehashed, ad nauseum (and I mean that literally ). The DPReview guys have answered the misconceptions in great detail - some misconceptions I've seen you posting in this thread for instance.

They have made their cases to skeptical digital imaging experts (people who are engineers in the field), generally, after much toil and trouble, to those experts' satisfaction, as far as I've seen.

But every few months, the same non-conspiracy boils to the top again, this time with new actors who are acting in good faith and making arguments that seem logical and common sensical, but which are either based on some degree of ignorance regarding the topic, some degree of ignorance about DPReview's testing regimes, or a combination of those things.

The problem is that they've been here before, but the new crops of people who come in and make these arguments every few months don't bother to go back and familiarize themselves with all of the details before coming up with their brilliant arguments that they're simply 100% certain are correct.

So I understand the DPReview team's annoyance at having to deal with this same topic, over and over again, with people who haven't done the hard work to learn the details about the topic and/or the details about how DPReview runs its tests.

tex

Fair enough, tex. Now me being someone who likes to learn, would you mind setting me straight on the misconceptions I may have helped to perpetrate?

Jack

Jack, here are four posts I have written in the last couple of days on the subject, each of which quotes and links to a number of outside sources  - previous statements by Andy Westlake and Richard Butler, articles at DPReview, Articles at DxOMark, an article at Imatest, the Wiki article on Film Speed. Basically, a number of the important sources that one should really read if he wants to get a good understanding of the topics - both the question of ISO, the question of DPReview testing regimes, and the question of how ISO Settings (DxO Manufacturer ISO) relate to ISO Sensitivity (DxO Measured ISO).

http://forums.dpreview.com/forums/post/51036625

http://forums.dpreview.com/forums/post/51037198

http://forums.dpreview.com/forums/post/51042816

http://forums.dpreview.com/forums/post/51042893

It's all there, I believe. You may want to skip my pontifications and go straight to the sources I link to and quote.

Good luck!

tex

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