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11-27-2009, 02:20 AM   #16
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Isn't much in it

Anyway , just considering the price tag of the k-x compared to what the k10d cost when it came out.

11-27-2009, 10:51 AM   #17
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QuoteOriginally posted by rjm Quote
The images coming from the cameras are 6MP, so you are seeing reduced noise in both due to the downsampling (pixel averaging). I did this to produce a level playing field, to simulate what the output would look when printed a at fixed size.

I chose in-camera JPEGs to give the K-x the full benefit of it's more modern PRIME II image processor. This is meant as a results test, not a sensor test. The WB, contrast settings are slightly different, you'll have to factor that into the evaluation as best you can. It's also under fluorescent lighting, which doesn't help.
Equalizing for resolution is always a good idea, but not using the camera's internal jpeg engine. I loved the K20D's jpeg engine, don't like the K-x's at all. It just can't deliver the level of resolution that's found in the RAW file.

The problem is that different cameras use different in-camera downsampling methods. One camera will cut the interpolation and give you a really sharp image, while another camera will downsize the full-resolution interpolated jpeg and give you something a little mushy. Processing from RAW and using the same downsampling algorithm for both would be a more consistent method.

Your second test is better (imo) and illustrates the type of softness I've been seeing in a lot of my K-x shots. I've come to the tentative conclusion that it has something to do with the SR system, somehow, because when I get an image from the K-x that's sharp (usually with high shutter speed), it's SHARP. Sadly, that's not most of the images I get. I get better results turning SR off at higher shutter speeds, but on a tripod it's often still a problem and I can hear the SR buzzing around even with the MLU timer on. I really hope pentax takes a look at this soon.
11-29-2009, 05:48 PM   #18
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QuoteOriginally posted by er1kksen Quote
Your second test is better (imo) and illustrates the type of softness I've been seeing in a lot of my K-x shots. I've come to the tentative conclusion that it has something to do with the SR system, somehow, because when I get an image from the K-x that's sharp (usually with high shutter speed), it's SHARP. Sadly, that's not most of the images I get.
Well, the second test was with SR off, so it's unlikely to be the cause.

Trust me, I know *really* well what you are going through right now. My orange K-x is on ebay as we speak as a result. I gave up, in short.
11-30-2009, 10:19 AM   #19
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QuoteOriginally posted by rjm Quote
Well, the second test was with SR off, so it's unlikely to be the cause.
Trust me, I know *really* well what you are going through right now. My orange K-x is on ebay as we speak as a result. I gave up, in short.
That's the thing, is that I'm wondering if "off" is really "off." When it's "on," the motors work to move the sensor around to counteract camera shake. When it's off, the sensors are still working to hold it in a centered position. I'm starting to wonder if there are unintended vibrations from those motors in the "off" mode. This would make sense, especially if they were random, since some of my tripod-mounted MLU images are tack sharp while others exhibit that irritating softness, often for the exact same scene.

On the other hand, I'm also wondering if it's possible that that bombastic little shutter mechanism is producing too much vibration at certain shutter speeds (not necessarily the mirror flap but the shutter itself), which would seem to relate to the fact that I'm observing the most consistent softness between 1/100 and 1/160. Images above and below those speeds are much more likely to be sharp.

I've got a major trip approaching soon, which was my main reason for buying the K-x, so I really can't afford to sell it and switch to something else right now. I just hope some firmware update soon will address this softness issue so that my K-x consistently delivers the sharpness I know it can achieve. Take care of that and the battery issue and we're all set.

11-30-2009, 08:17 PM   #20
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I don't know what it is about that K-x sensor that makes pens disappear.
12-01-2009, 08:07 AM   #21
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QuoteOriginally posted by yustr Quote
I don't know what it is about that K-x sensor that makes pens disappear.
I wonder if it can do the same with powerlines?
12-01-2009, 04:48 PM   #22
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Pentax K-x soft images

At first I saw that AF was out of calibration, mine needed -90 um correction, but there are still some too softy images sometimes.

SR can be the problem as well, I did some tests with DA 21 Ltd and got 100% sharp photos, I do not know why ? But DA*55 and DA16-45 are not doing so good. The problem is not in focus because I checked it with LV.

There is another strange problem, if you shoot with flash at Av, exposure is quite often metered according to the background, i.e something 1/15 to 1/30. This can be tweaked in manual mode only to 1/180 but no other methods exists in my opinion.

In tripod shooting, the camera definitely is vibrating with lighter tripod, the worst case is in camera HDR and there is no mirror lock for HDR or exposure bracketing modes. It gets better with heavy tripod not so easy to carry with.
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