Preview display "quality"

[chris_livsey]

In the article on IR with the M8 in LFI 5/2007 the author talks about using the M8 to assess accuracy (of focusing with IR ) and coments "I selected DNG ... Had I run DNG + JPG instad, the display would have only shown the Jpeg picture making my evaluation of the focal plane considerably less reliable."

Could one of the computer gurus comment on this ?

How is the preview from DNG generated ? Is it ISTR "embeded" in the data or is processed in camera from the DNG file ie converted ? Is the preview quality going to be "better" as suggested by the author than a Jpeg preview ? Going futher down this line does the menu selection of sharpening/contrast etc show in the preview display for Jpeg images ?

[lars_bergquist]

As far as I know the camera uses the embedded jpeg in the DNG file header. Even if the camera could dechipher DNG files, which it cannot, you could go to the bathroom while waiting for it to come up on the monitor.

The old man from the Age of B.C. (Before Cuneiform)

[chris_livsey]

Originally Posted by lars_bergquist

As far as I know the camera uses the embedded jpeg in the DNG file header. Even if the camera could dechipher DNG files, which it cannot, you could go to the bathroom while waiting for it to come up on the monitor.

The old man from the Age of B.C. (Before Cuneiform)

I thought that was the case so what is the author's basis of seeing improved quality on the display from the embedded Jpeg from the DNG to the "native" Jpeg ?

[ho_co]

Chris--
I raised this same question after seeing the LFI article, and the forum didn't come to a conclusion.

You've put the question much more succinctly and in better detail, and I'm hoping you get an answer.

Seems that either:
a) our conventional wisdom is correct; or
b) Bültert knows something we don't.

Perhaps the solution is try it ourselves? But that's no fun... I found it quite difficult to judge image focus from DNG as suggested, so if JPG is worse, it will be really bad.

--HC