Problems with the K7 sharpness

[michael_elenko]

<p>Laurentiu,<br>

I found out about the Lumolabs article from DPR posts a couple of weeks ago. Not owning a K-7 I didn't delve in deeply, but the authors snagged me for a longer stay because I thought (and still do now) that it was well written. It's great that you haven't had those issues, but with manufacturing engineering being inundated with sometimes conflicting requirements these days, I tend to believe that it's real <em>for some bodies</em>. I'd put this in the same slop bucket as the early versions of the DA* 16-50mm lenses that freaked quite a few folks out.</p>

<p>Perhaps Daniel's is one of them; perhaps not. I do hope he provides some followup in the future after more formal testing. I do admire his attitude about the whole thing.</p>

<p>ME</p>

[yosh]

<p>Thanks Michael. Extensive therapy helps :-)</p>

[yosh]

<p>Michael and Laurentiu,<br>

Well I finally read the above mentioned white paper. I have to admit that about 90% of it was just way over my head (never any good at calculus). I did do the test we've been discussing using a ruled piece of paper - still haven't gotten around to printing the sample grid provided by one of the above links. And found that the line that I focused on (I put a small circle on it so I could tell which one it was) was sharpest with those fore and aft getting progressively fuzzier at pretty much the same rate. So it isn't a focus issue. So I am forced to conclude that what the white paper is discussing is the problem. As I said I didn't understand most of it but I was able to glean the basics, that plus the final paragraph in layman's terms which helped so much. Bottom line - the shutter slams the camera around, noticeable at certain shutter speeds - and the way to fix it is to use a very heavy tripod. Perhaps down the road there will be a firmware update that can address the sensor processor's inability to compensate. But then again, maybe that isn't possible. <br>

Thanks again for all your help!<br>

Daniel</p>

[laur1]

<blockquote>

<p>So I am forced to conclude that what the white paper is discussing is the problem.</p>

</blockquote>

<p>You're not forced to conclude that, because the article doesn't cover all the possible issues that can cause blur and your experience doesn't even fit the scenario given in the article as most evident for the issue (wide angle lens, far subject):</p>

<blockquote>

<p>We recommend to use a sharp wide angle lens with your K-7 (e.g. DA 4/12-24, DA* 2.8/16-50) or to stop down enough to get sharp images in the center. Also, please do manual focus your lens as autofocus (AF) isn't always giving best results with super wide angle lenses pointed at a distant subject. Then photograph the same scene at the shortest focal length with an exposure time of 1/80 s and 1/25 s, five shots each.</p>

</blockquote>

<p>ME: My camera may have that issue, but I don't shoot far away subjects with a wide angle at 1/80 to be able to notice such effect. I don't know whether the article's findings apply or not to my camera, but I don't think they explain the blur Daniel is getting - that is worse than what the article describes and is obtained in different shooting conditions.</p>

[yosh]

<p>Ok, I'm back. Don't know if anyone will be updated on this thread or not but I'm going to post anyway. I've done a little work since the last time I've posted and have shot two weddings plus a host of other shoots as well with the K5 and have this to report. First, my K5 focus point was off. Using the focusing chart (as well as other gradient focusing methods I determined that the focus point was a bit beyond where the little red dot lit up in spot focus setting. My original test shooting a basically perpendicular to a flat surface didn't show this. What I was calling unsharpness was in fact out of focus. I have adjusted that using the cameras AF adjustment settings.<br>

Second, I screwed up. When I brought both the K20's and the K7's raw files into Photoshop I did not take into account that I had set the programs raw defaults to sharpen the K20s files. I had not set the program to sharpen the K7's so the initial test was skewed to start with. Zeroing out the raw defaults for both cameras and redoing the test I find that the K7 is still not quite as sharp as my K20s but only ever so slightly. Barely noticeable.<br>

Having done the above mentioned shoots I must say that I am impressed with the K7's focusing speed and accuracy, it's improved dynamic range, even with the camera's D-Range settings turned off and it's white balance accuracy. It has a pleasure to shoot with!<br>

Thanks again for all of your input and help!</p>