Originally posted by RiceHigh Dang you are still funny. For years you quote DP Review as the know all be all source of Pentax "criticism". Now that Phil, whom in the past you petty well had glorified as "THE expert" thinks the DR of the k20 is pretty darn good, you have to find another source of "bad data"... Tooo funny.
Phil:
Pentax K20D Review: 20. Photographic tests (DR):
Camera (ISO 100)
Shadow range Highlight range Usable range
Pentax K20D -5.8 EV 3.2 EV 9.0 EV
Canon EOS 450D -5.1 EV 3.6 EV 8.7 EV
Sony DSLR-A700 (200) -4.9 EV 3.9 EV 8.8 EV
Olympus E-3 -5.8 EV 3.0 EV 8.8 EV
Pentax K10D -4.5 EV 2.8 EV 7.3 EV
The Pentax K20D: a RAW review, page 3 I would think that this DR limitation will come out when the camera is reviewed by the best of the review sites such as DPReview and Imaging Resource
(
Digital Cameras, Digital Camera Reviews - The Imaging Resource!).
Apparently that is not so.... so far. I'm waiting for the imaging resource review.
So who to believe? I'm soo confused
And as to your new found friend, after I learned that ACR may not do a linear exposure correction (as it should) I really don't trust it... can blow highlights when it shouldn't and it can create more noise. As far as I'm concerned ACR has never really been the best converter (only the most used).
Anyway while looking for the ACR "exposure adjustment problem" I found this for you....... it's pretty funny actually:
Luminous Landscape Forum > Zone System, light metering and neutral gray
Oh as to Gordons, Oleg's and if you add john Sheey's data. The general consensus was the K10 had a tested DR that was considerably high (at the time the highest they tested I believe). Unfortunately the VPN made it a bit unuseable.
They did conclude that the k20 was a stop lower than most of the current cameras. Data that is completely contrary to dpreview as far as I can tell.....
Apparently somebodies methods (or sample variation, or minor assembly line revisions) is at fault.
BEST thing Trust your eyes... DR of all these cameras, in reality and practice, is probably close to equal....
Good technique, and a good RAW converter, will outweigh good theoretical stats and day. At least w/ DSLR's...
Pentax K10D daylight image noise test [Archive] - Aussie Phorums From what I gather from people who have tested the K10D more objectively,
it is the #1 DSLR for dynamic range at ISO 100, at the pixel level. The
1DSmkII might be close at the image level (dividing noise by the linear,
one-dimensional pixel resolution).
It has no real optimization at higher ISOs, though, like Canons do. Most
cameras don't; they have a single at-photosite read noise, and multiply
it in amplification, and then add the analog noise of the ADC, so the
total read noise as measured in electrons only improves ever so slightly
at higher ISOs, as opposed to dramatically with Canons. For most of
these cameras, the only benefit of higher ISOs is the brightness of the
review image; under-exposing at a lower ISO may provide almost the same
quality, without sacrificing highlight headroom. Quantization is not a
significant issue with these analog noise levels.
The standard deviation of an ISO 100 blackframe from the K10D (according
to my source) is about 0.9 DN/ADU. The Fuji SLRs, the Canon 1D* cameras,
start at about 1.3. Non-1D Canons are at 1.65 to 2.1, and most Nikons
are at about 3.0 or so. Some cameras clip the RAW data at black, and
some don't. These values are normalized to those that don't, as the
noise is only clipped near black in the cameras that do clip at black,
and not at higher luminance levels in any camera (blackframe noise must
be multiplied by about 1.64 for black-clipped RAW images).
With the K10D black noise at only 0.9 DN/ADU there is probably a little
bit of quantization noise, so ISO 200 probably is a bit better than ISO
100 under-exposed (ignoring the stop of highlights), so it has more value
than just a brigher review image or default conversion or JPEG.
The probably reason that the extra DR is not noticed in many DR reviews
is that the images are rendered with normal transfer curves, leaving the
extra shadow ranges down in the dark, where you can't distinguish them.
You really need to boost the shadows to appreciate the difference. There
is also the issue of where the camera exposes the middle grey in the RAW
data; this can vary quite a bit from camera to camera, and converters are
not consistent in the way they utilize RAW highlights.
John P Sheehy