Some of you may have noted that Imaging Resource (www.imaging-resource.com) have posted a link to the German Pentax website where two DNG raw images from a Beta 0.2 camera are posted (and thus presumably sanctioned by Pentax?). I downloaded these two files (a wide and a telephoto of a church) and can make the following statements after analysis, with the qualifications as stated:

The following observations are very unlikely to change between the beta version and the production versions:

1) These files confirm JohnCPentax's telling us that DNG's from the K-7 are now losslessly compressed. The compression scheme used is not the multi-tiled scheme used by the Adobe DNG Converter application but is compressed as one large block, both of which schemes fit into the DNG compression specification.

2) The embedded colour gamut matrix in the DNG files is again slightly different than the K20D, which was different than anything before it. The chromaticity endpoints as in these beta files indicate that the camera may tend to produce slightly more saturated reds, quite a bit less saturated greens, and about the same blues as the K20D. Pentax colour is generally quite accurate, so this is unlikely to be a problem, although the reds may tend to clip when processed to sRGB or AdobeRGB a little more.

3) The layout of the sensor is very similar to that of the K20D but Pentax no longer encode the completely garbage values on the right side as for the K20D (likely to reduce file size) and now seem to have two rows on the top as well as the 12 on the bottom of the sensor that are masked to light and not part of the images. Also, the dark masked-to-light area on the right side of the sensor (in landscape mode) is now narrower at only 52 columns rather than about 96 columns for the K20D, indicating that the new PRIME II imaging processor may now use a new algorithm to determine the black offset compensation and apply it to the light-exposed photosite rows. Basically all this tells us is that it indeed is a redesigned sensor as to layout, that it may be used somewhat differently as to black compensation, and that it is likely still scanned horizontally as the K20D was, as well as having the required 4 channel readout for the required increased scanning speed.

4) I push processed and contrasted the raw data for flat textured dark patches to extreme levels to see the RGB noise" speckles" and could detect no signs of Vertical/Horizontal Pattern Noise (VPN/HPN) in the images in areas of dark flat texture. Patterns may appear to some extent for extremely high ISO images as it is said to do for the K20D for some cameras, but I could not detect it pushing these low ISO images.

Which brings me to the limitations of testing these images, as both were shot at ISO 200 with Dynamic Range Expansion (DRE) set to On according to the Manufacturer Notes in the EXIF data (PhotoMe); this means that the images were actually shot at an ISO 100 internally. Further, one should not consider the noise found here as final in that all of the firmware, the sensor, and the electronics, may be at a pre-production state and may be improved before the production cameras are released. One would think that production cameras would be better than this and not worse (hopefully). What I found was:

That the black read noise (and all other noises) of this Beta 0.2 camera was very similar to that of the K20D at ISO 100, which was a little disappointing (although still hopeful that production versions will be better).

If the black read noise is not reduced below this level, the Dynamic Range (DR) of the K-7 will not be any better than that of the K20D, nor will the high ISO capability be improved, and if there are any improvements seen in the JPEG outputs it will likely be due to stronger Noise Reduction (NR).

Now I know that a DR limitation does not bother many users who never "push process" their raw images or compress a wide DR into a narrower one for display on a contrast limited viewing device or paper, but unfortunately, if black read noise is not improved this is the one parameter related to image quality across the ISO range that the K-7 does not at least come close to matching for its major competition in the same price range. I still hope that Pentax may be able to improve this without NR in production cameras, but fear that it may be a limitation of the Samsung sensor design itself.

Just for your consideration while we wait for production samples.

Regards, GordonBGood