Photographic Dynamic Range (PDR) is a More Useful Measure than the DxOMark Landscape Score

Started Apr 17, 2015 | Discussions thread
OP bclaff Veteran Member • Posts: 8,712
Re: Regarding PDR of Sony A7S at ISO 409600

Horshack wrote:

bclaff wrote:

I assume you're trying to show that the Sony A7S has more DR than the 0.93 that PDR predicts at 409600.

But I think you're forgetting that there is an acceptable quality factor built in.
When I put your image on my screen at 8"x12" and view it at a reasonable distance I don't find it acceptable (usable perhaps, but not acceptable).
PDR predicts that the brightest 0.93 stop in such an image if ETTRed would be acceptable. (Maybe up by those stairs)
I have some other input on this matter but since it's really not directly on the topic of this thread I'll start another when I get my act together.

You proposed two foundations for your 20:1 SNR cutoff - human sensory limitation and acceptable quality. I believe this image demonstrates we can perceive more than the 1EV in this image. As for what is acceptable quality that'll always be up for debate.

No disagreement.

Just to recap.

I chose SNR = 20 which ISO says is "good" (They also say SNR = 40 is "excellent" )
ISO also says SNR = 10 is "acceptable"
As I understand it, SNR = 5 is considered the limit of usable feature detection.

So certainly, depending on what you are after, you could add stops to the PDR value to suit your particular purpose.


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