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03-17-2010, 08:26 AM   #1

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Imaging Resource reviews K-x - in full

Imaging Resource have posted their full review of the K-x:

Pentax K-x Digital Camera - Full Review - The Imaging Resource!

Before they had only snippets, now it's the full box-and-dice.

Some very good detailed analysis, esp here for dynamic range and Imatest:
Pentax K-x Digital Camera Imatest - Full Review - The Imaging Resource!

image quality:
Pentax K-x Digital Camera Imaging - Full Review - The Imaging Resource!

and NR:
Pentax K-x Digital Camera Raw - Full Review - The Imaging Resource!

They really liked the printed output from the K-x too.

A few things they didn't like (AF indicators, battery life etc) but overall the K-x came through the IR testing ordeal very well.

03-17-2010, 08:37 AM   #2
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Everywhere you go, this is the camera to consider very seriously by all reviewers. Look at where it ranks with DxO It's 19th on the list and with the exception of the D90 and D5000 which are just barely above it, the top 21 cameras are all either FF or MF. That's astonishing for an "entry level" camera!! I have to note the Canon 7D came in 31st.

Now if we could just figure out how to get the general buying public to notice this. But I won't rant about Pentax marketing once more.
03-17-2010, 12:06 PM   #3
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I really wish t hey did this page ( Pentax K-x Digital Camera Imatest - Full Review - The Imaging Resource! ) not using the default "bright" for JPEG, but natural.

I've switched from RAW to RAW+ because I've gotten lazy on noise processing, and this almost made me switch back to RAW only until I realized they kept noting how the K-x performed in JPEG because of its default "bright" setting. I'd love to see numbers on natural.

As for printing, wow, I never thought about printing high ISO's to that big, maybe I will try it out:

ISO 3,200 shots also look decent printed at 13x19 inches.

ISO 6,400 shots are generally usable at 11x14, remarkably, but of course better at 8x10.

Depending on the subject ISO 12,800 shots are usable at 8x10, though contrast is increased and there's some blotchy noise in the shadows. At 5x7 inches, though, no one will notice.
Interesting bit:
The chart above shows consolidated results from spatial frequency response measurements in both the horizontal and vertical axes. The "MTF 50" numbers tend to correlate best with visual perceptions of sharpness, so those are what we focus on here. The uncorrected resolution figures are 1,371 line widths per picture height in the horizontal direction (corresponding to the vertically-oriented edge), and 1,477 lines along the vertical axis (corresponding to the horizontally-oriented edge), for a combined average of only 1,424 LW/PH. Correcting to a "standardized" sharpening with a one-pixel radius increased the resolution score by quite a bit, resulting in a much higher average of 1,992 LW/PH. The corrected numbers are slightly below what we'd expect from a 12-megapixel DSLR, though not too far off the mark.

To see what's going on, refer to the plots below, which show the actual edge profiles for both horizontal and vertical edges, in both their original and corrected forms. Here, you can see that very little if any in-camera sharpening is applied in the horizontal direction (undersharpened by 20.4 %), as well as in the vertical direction (18% undersharpened), explaining why standardized sharpening increased the MTF 50 numbers by a fair amount.

As with the K-7, we found these results a little paradoxical, given that we definitely saw sharpening artifacts in most of our "real world" images. (The far-field shot and the Still Life, in particular.) In-camera sharpening appears to vary depending on the density level of structures in its images. At very high and low densities (the black and white areas on the resolution target), it applies almost no sharpening at all. For densities away from the extremes of the tonal scale (the branches against the sky in our far-field shot and some of the details on the bottle labels in the Still Life shot), more sharpening is applied, resulting in slight halos around contrasting objects.

Last edited by Eruditass; 03-17-2010 at 12:14 PM.
03-17-2010, 12:38 PM   #4
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Wow what a useful review! Finally I see sample adjustments of parameters!

Thank you,

03-17-2010, 01:55 PM   #5
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I still take DXO with a pinch of salt.

Having downloaded many pics raw & jpeg and put through my pp workflow I can honestly say that the 7D bests my K10D (and I really love my 10D) by quite a margin in all areas of IQ.

Many other tests have shown that the 7D is the aps-c dslr of the moment besting the Nikon 300s

Let your eyes do the choosing

The kx is a great little cam yet the masses still bypass to buy Canon, Nikon and Sony

No brand awareness = low sales / low sales = higher prices for lenses due to low volumes & no shelf presence.

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