Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-13-2009, 03:45 PM   #1
New Member




Join Date: Nov 2009
Location: Temuco
Posts: 13
How can I get good image quality from a K-x??

Dear all,
after one week playing with my new K-x, trying to learn all its many functions, bells and whistles, I have arrived at the point where I suspect that this camera's image quality is is not nearly as good as some reviews suggest. I'm consistently getting an image quality that's well below the one produced by my cheap 3 megapixel point&shoot camera, which cost one fifth as much as the K-x!

The photos from the K-x have very low contrast, with a brownish fog over everything. If I try to correct for this by cranking up the contrast and saturation controls in the image processing software, I can get rid of that brownish fog only at the cost of getting ridiculously grainy images.

It doesn't matter whether I shoot in raw or in JPG. I have tried several programs, including FastStone, DCRAW, and Photoshop. I have shot through six different lenses, three of which are of excellent quality and consistently produce excellent, contrasty photos with my film cameras. I have carefully watched to avoid overexposure with the K-x, which happens commonly and further degrades image quality. Most of the testing has been done at ISO 200; at higher sensitivities, results get even worse, specially above ISO800.

Looking at the sensor surface, I cannot see any layer of dirt or anything like that. But maybe the sensor IS covered with something that causes this fog. It may be hard to see.

Regardless what I do, the low image quality remains, and I'm starting to suspect that I have essentially flushed my money down the drain. I won't find much use for photos of this quality level.

I'm pretty frustrated at this point, and out of ideas of what else to try.

Does anybody have a recipee of how to get decent quality from the K-x?

12-13-2009, 03:58 PM   #2
Pentaxian
JohnBee's Avatar

Join Date: Sep 2008
Location: front of computer
Posts: 4,496
QuoteOriginally posted by Manfred Quote
The photos from the K-x have very low contrast, with a brownish fog over everything. If I try to correct for this by cranking up the contrast and saturation controls in the image processing software, I can get rid of that brownish fog only at the cost of getting ridiculously grainy images.

It doesn't matter whether I shoot in raw or in JPG. I have tried several programs, including FastStone, DCRAW, and Photoshop. I have shot through six different lenses, three of which are of excellent quality and consistently produce excellent, contrasty photos with my film cameras. I have carefully watched to avoid overexposure with the K-x, which happens commonly and further degrades image quality. Most of the testing has been done at ISO 200; at higher sensitivities, results get even worse, specially above ISO800.

Looking at the sensor surface, I cannot see any layer of dirt or anything like that. But maybe the sensor IS covered with something that causes this fog. It may be hard to see.

Regardless what I do, the low image quality remains, and I'm starting to suspect that I have essentially flushed my money down the drain. I won't find much use for photos of this quality level.

I'm pretty frustrated at this point, and out of ideas of what else to try.
Try another camera/Kx, sound like yours definitely has issues.
12-13-2009, 03:59 PM   #3
Inactive Account




Join Date: Jun 2007
Posts: 75
Manfred, you should post a few examples !
12-13-2009, 04:02 PM   #4
Forum Member




Join Date: Oct 2009
Location: west chester
Posts: 63
obviously everybody else is not wrong about this camera, including myself! HA! have you tried shooting at full auto? i've had great pictures JUST doing it that way and not playing with manual mode or any other settings.

12-13-2009, 04:51 PM   #5
pdo
Senior Member
pdo's Avatar

Join Date: Sep 2008
Location: Westminster CA
Posts: 264
Seems like anyone who upgrade from P&S to DSLR always complain about lack of contrast, image quality sucks. You just need some time to get to understand your new DSLR and learn how to post process it in photoshop.
12-13-2009, 05:26 PM   #6
Forum Member




Join Date: Oct 2009
Location: Colorado
Photos: Albums
Posts: 91
The brown fog doesn't sound right. I have a Kx, and I don't see anything like that. I would exchange the camera.

If you post some photos, we might be able to help more.
12-13-2009, 10:17 PM   #7
Veteran Member




Join Date: May 2007
Location: Central NJ
Posts: 469
Here's a tip: If you are going to complain about image quality issues, post example pictures.

As for people saying the brown fog isn't right, could be an actual problem, or it could be a DSLR newbie complaining about auto white balance under bad tungsten light where the iso is being pushed.

But that's just as speculative as saying the camera is defective. Posting samples makes it easy to give good advice.
12-14-2009, 08:06 AM   #8
Forum Member




Join Date: Oct 2009
Location: Colorado
Photos: Albums
Posts: 91
QuoteOriginally posted by Manfred Quote
...

I'm pretty frustrated at this point, and out of ideas of what else to try.

Does anybody have a recipee of how to get decent quality from the K-x?
Manfred,

Try resetting the camera to factory defaults, then take a shot in P mode with the kit lens or any DA lens.

To reset the camera, you need 2 resets. The first resets the Camera, Playback and Setup settings. The second resets the Custom settings. Instructions are in the Reset pages of your manual.

Reset Camera, Playback, Setup:

press Menu
scroll to Setup (wrench icon) screen 3
select Reset
then OK to confirm

Reset Custom:

press Menu
scroll to Custom (C) screen 4
select Reset Custom Functions
select OK to confirm

Now take some shots in good light without adjusting anything. Ideally try outside in sunlight.

If you still have the brown fog, I'd exchange the camera.

12-14-2009, 08:46 AM   #9
New Member




Join Date: Nov 2009
Location: Temuco
Posts: 13
Original Poster
OK, I kept experimenting. Part of my problem is obviously in the processing. regardless what I do, when processing the raw files I can get AT BEST the same quality provided by in-camera JPGs. I have tried FastStone, also DCRAW fed into Photoshop 7, fiddling for days with all imaginable adjustments. So, either I'm still doing something very wrong, or the JPG processing inside the K-x is very well optimized for what that sensor can give.

Trying another K-x is not an option. I live in Chile, ordered the K-x from B&H, and any return and replacement would cost me around 400 dollars in shipping and Chilean taxes.

Yes, I have tried fully automatic mode. The results are no better, and tyically the camera will chose a combination of aperture, speed and sensitivity that's less good than what I can choose myself.

Here is a test shot. I make no claims as to artistic quality of this. It's JUST a test shot, straight out of my window. It was made with the Pentax-A 50/1.4 lens, stopped down to f/8, from inside the house (window open, of course), so that there is little stray light on the lens. ISO 200, manual white balance (daylight), custom image set to natural, with the default settings for that mode except that I selected fine sharpness. Highlight correction ON, shadow correction OFF. Maximum quality JPG generated by the camera, downsampled to 640x480 by FastStone, without any further processing, saved as 85% quality JPG. The day is bright and sunny, blue sky except for some clouds near the horizon, very clear long-range visibility. Shot at roughly 10:30 AM, sun angle of about 45 degrees. It's spring here, and the vegetation is intensely green.

And the second image is a 100% crop from the center of this image. Resolution is as good as one could expect, but I just can't like that color and contrast! Those flowers are very intense red in true life.

So, any suggestions of how this can be improved? Or any comfort, in the way that what I'm getting is OK, and that I just had too high expectations?
Attached Images
View Picture EXIF
PENTAX K-x  Photo 
View Picture EXIF
PENTAX K-x  Photo 
12-14-2009, 08:53 AM   #10
Veteran Member




Join Date: Mar 2007
Location: Toronto (for now)
Posts: 1,749
You need to use your histogram, you have some speculative highlights (the white buildings) that freaked out the camera so it underexposed by about 0.7 to 1 Ev.

From there use the brght rather than natural setting for more punch. Regarding white balance, if your greens are a little brown and yur reds not stark enough ...... well that's what RAW s for.
12-14-2009, 09:13 AM   #11
Veteran Member




Join Date: May 2009
Location: Twin Cities, MN
Posts: 2,869
If you want to pull an intense red from a raw file, wouldn't you ideally want to shoot something red? I don't think your expectations are in line with your subject. If you want a more intense red, as suggested you should move over to the bright mode. The subject overall looks slightly out of focus as well (looks to be focused on the closer foliage - F8 isn't the end all be all for focus, just a guide for reasonable focus).

The center looks somewhat hazy also, likely due to the time of day the photo is taken (with strong direct overhead sunlight) with a broad landscape, you can only go so far through the atmosphere before it will start to affect the image as well. (I am guessing this is the brownish fog you referred to in the original post). How is the air quality where you live? Looks to be a pretty green place, but are you close to a larger industrial area? If you live in a hazy area, taking photos at this time of day you simply won't be able to avoid the haze/fog. Perhaps a circular polarizer might help to cut through it, or even a UV haze filter (though I hate them personally!)

How about walking down to that tree and snapping some jpegs of the red flowers with the different customer image settings (along with raw) and seeing those results? (posting them too...)
12-14-2009, 10:29 AM   #12
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
QuoteOriginally posted by Manfred Quote
OK, I kept experimenting. Part of my problem is obviously in the processing. regardless what I do, when processing the raw files I can get AT BEST the same quality provided by in-camera JPGs.
Is there a reason you expected otherwise? RAW provides no particular advantage over JPEG if all you are trying to do is match the camera JPEG. The advantage of RAW comes if you need to *alter* the image in some way - to make it brighter, change the color, etc. While it is possible to make these kinds of adjustments to a JPEG file, the results won't be as good as if you make those same adjustment to a RAW file. For small adjustments, the differences won't be noticeable, but for larger adjustments, the differences can be quite large.

QuoteQuote:
So, any suggestions of how this can be improved? Or any comfort, in the way that what I'm getting is OK, and that I just had too high expectations?
I have no idea what you were expecting, but this image looks fine to me for what it is - a quick snapshot of a not very interesting scene. Those flowers are just tiny dots in the distance, and as far as I can tell from your crop, you didn't nail the focus there, plus you may have clipped the red channel there. If you want impressive red flowers, you might consider shooting from a shorter distance. And aside from the fact that it appears there was probably a fair amount of moisture in the air, which will *always* reduce contrast when shooting distant objects, I don't see anything that could remotely be called a "brownish fog".

It is possible your monitor is very poorly calibrated and you are seeing something very different than I am. Do you own calibration hardware?

Last edited by Marc Sabatella; 12-14-2009 at 10:35 AM.
12-14-2009, 11:19 AM   #13
New Member




Join Date: Nov 2009
Location: Temuco
Posts: 13
Original Poster
Alfisti, I do use the histogram a lot! On every shot I have to check them (the color histograms) to make sure the camera didn't blow any of the colors. I often have to re-shoot with some EV compensation. I re-shoot until I get a shot that does not saturate in any color, on any pixel, but has the lightest pixels as close as possible to the saturation level.

Actually, this instant review function with histograms for each color is a great tool!

OK, I now shot some comparison photos in BRIGHT mode. It's better, indeed. But still not really good. Seems that I will have to fiddle with the in-camera contrast and saturation settings. I hadn't done that much, because I was shooting in raw mode and processing in the computer, but that has given me poor results, with the pictures going grainy more quickly than I got a decent contrast. The in-camera controls work better.

I know perfectly well that I should shoot in raw mode and process the images in teh computer. And I started that way, and fully intend to go back to that. It's just that I found it quite frustrating, probably due to a lack of high quality software, and even more so, lack of practice in doing this.

My only significant practical experience with photo adjusting is when I did a lot of slide scanning. I used Ulead PhotoImpact back then. But this program is pretty dated now. I don't even know if the old version I have would run on my Windows XP PC!

What I was using now for raw processing was either FastStone (current version), or DCRAW (current version) feeding into Photoshop (old version 7). With the DCRAW-Photoshop combo, I tried using linear 16 bit TIFF files, and also doing the gamma correction in DCRAW and then using either 16 bit or 8 bit TIFF files. It doesn't seem to make much difference in teh results - the images I get are MUCH worse than the JPGs straight off the camera! That's what triggered my desperate post! I hadn't even noticed yet that the JPGs from the camera are better than what I was getting from my very raw raw processing (pun intended).

Paul, in these test photos I was not really looking much at the red. I was looking at overall contrast, color correctness, and grain. Teh comment about the red flower was just incidental.
I have shot macros of those red flowers, and also relatively close photos of the flowering trees. I found that I have to set the camera to an EV compensation between -2 and -2 2/3 to keep it from blowing the red and turning these flowers some shade of pink! Withthe very strong EV compensation, the flower's color looks quite good, but the background foliage has the brownish cast. This foliage is bright green in true life, and teh scene was lit by direct sunshine and a blue sky. A sample is attached. I slightly sharpened that image after downsampling, to optimize it for the small size. No other processing was done.

The samples I posted are not out of focus. Actually I focused the lens just a tad short of infinity, to get both the distant objects and that vegetation with teh red flowers (which is at about 80 or 100 meters distance) into focus. The foreground is of course out of focus.

I chose f/8 because that is about the upper limit of the sweet range of this lens when used on the APS format. So I get maximum depth of field possible before starting to degrade the ultimate resolution. At f/11 the resolution is already visible lower, due to diffraction. And at 5.6 I don't gain anything in resolution.

I'm old in photography. Just new to DSLRs.

The haziness you see in the cropped shop is precisely what I'm complaining about! It is NOT really there. It just shows up on the photos!

You apparently didn't notice my statement about the time this photo was shot: 10:30 am. The sun rises at around 7:00 here in this time of the year, and reaches its highest position at about 13:50. I'm at close to 40 degrees latitude. So the sun DEFINITELY wasn't anywhere close to direct overhead! Just look at the shadows, and you can judge the sun angle. It was pretty close to the optimal to get good color!

The air was extremely clean when I shot that photo. It rained yesterday, so any dust was grounded. There are no industries here. This region is fundamentally agricultural. There are times when there is smoke in the air, specially in autumn when some people burn off their fields as a way to prepare them for new planting. But definitely not now, in spring! The closest industrial plants are well over 100km away, and I have none upwind from my place.

I will eventually try filters. I have a circular polarizer, a simple UV filter, and also a strong haze filter. The polarizer will certainly increase color. But first, I want to get the camera to produce natural colors and contrast in its JPGs, and also I need to find out how to process the raw files to get a quality better than the JPGs. Otherwise the whole thing with raw files makes no sense!

OK. I have attached three pictures. The first two show the same scene again, at 14 hours, when the sun was almost exactly at its highest point. The first is shot is from the Kx in BRIGHT mode, with the controls of that mode set to teh default values, except for sharpness which was set to FINE, but still at the default value of the slider.
And the second picture is the same scene, shot by the cheapy point&shoot camera, immediatly after shooting it with the K-x. Both were downsized to 640 pixels wide (the format of the two cameras is slightly different though), and no other processing was done.
The contrast of the P&S is pretty accurate, while its colors are slightly over the top, but just slightly so. The K-x instead is still producing less contrast and less saturation than the scene has in true life, and the blue/yellow balance seems a bit off.

And the third photo is the flower, as explained above.

I suppose that from here I should simply play with the contrast and saturation controls of the camera to get the JPGs right. But what about raw file processing? Can anybody recommend a GOOD software for that, hopefully free (I'm not asking too much, am I)? I would like software that is able to display a histogram, separated by colors, while I'm adjusting everything. None of the programs I have can do that, and I really miss that feature!

And perhaps someone can recommend a good tutorial? To give you an idea of the level of tutoring I need: I do know how CCDs and CMOS sensors work. I'm an electronic engineer and have worked on astronomical CCD cameras for many years. But those CCDs are monochromatic. Color processing opens a lot of questions. I know what gamma is, basically, but the details of each curve, and why they are used, I don't know. I wonder why it is at all necessary to define a colorspace, why one cannot just use the white-balanced RGB channels for everything. As an old-standing hobby photographer, I have done unsharp masking for real, in the darkroom, so I know what it is (and I have found that most dogital photographers don't really know what it is!). But with image processing software, I don't know how they are really doing this process.
I have basic questions, such as which program REALLY does all the operations at 16 bits per pixel per color. It is suspicious to me that Photoshop 7 can open a 16 bit TIFF file, but then shows histograms in a scale of 0 to 255 only! Does that mean it immediately downsizes the data to 8 bits?

Lots of questions...
Attached Images
View Picture EXIF
PENTAX K-x  Photo 
View Picture EXIF
Canon PowerShot A400  Photo 
View Picture EXIF
PENTAX K-x  Photo 
12-14-2009, 11:47 AM   #14
Veteran Member




Join Date: May 2009
Location: Twin Cities, MN
Posts: 2,869
I did note the time you mentioned - I would've guessed it was between 10 and 2 anyways (shadows make this obvious). This is honestly a far less than ideal time of day to be shooting. Harsh, overhead direct sunlight (yes, 10-2 is all overhead!) is just not great lighting conditions.

The two new photos you have posted - the P&S (could we get a brand/model for reference?) you state looks over saturated, and yet the K-x resized image you're posting looks almost the same, with slightly less saturation and yet you're saying it has less contrast and saturation than the real world as you see it. This is leaving me baffled, I don't think you are ever going to get anywhere if all you are doing is photoshopping the hell out of these through-your-window shots.

Mark was also spot on with the haziness - that is moisture in the air, highlighted by the strong sunlight as a result of your shooting in the middle of the day - again, not an ideal time for photography (unless you are into IR!).

Based on the red flower photo, the camera has metered on the red flower, of course the background is going to be darker - it is still green, just dark due to exposure, I don't really see anything wrong with the image itself.

I think the last paragraph seems to sum up your perspective - you enjoy knowing the numbers, I could care less about them so long as the camera gives me the results I want to achieve. I'm not exactly sure where you can go except to keep experimenting, so good luck!
12-14-2009, 11:54 AM   #15
New Member




Join Date: Nov 2009
Location: Temuco
Posts: 13
Original Poster
Marc, thanks for making me feel better! If you say the picture looks OK to you, then it's probably just that I was expecting too much.

The thing with raw files and me is just this: I spent a lot of time reading reviews and comments, before deciding to finally buy a DSLR. In many places I read that the out-of-camera JPGs from Pentax DSLRs are generally not very good, and that one should rather shoot in raw mode, and process the raw files in the computer. So, when I got the camera, and first configured it, I set it to raw mode, and didn't even really try its internal JPG engine. That's part one of the problem.

Part two is that I'm fooled by te raw processing programs. I have zero previous experience with raw image processing. I found the Pentax-supplied program to be not very user-friendly, but what bothers me most with that program, is that it's unstable on my PC. It has crashed several times, almost all the time the mouse cursor flickers like mad, and it takes forever loading a picture. So I didn't do anything much with it, and looked for better software instead.

I got recommendations from several people to use FastStone for most general purpose work, and when I want high quality I should use DCRAW for conversion to 16 bit linear TIFF, and go with Photoshop from there. FastStone indeed works quite well, but since I wanted to test first what this camera can deliver, I went to DCRAW and Photoshop. And that means, of course, endless possibilities for messing up the settings. So far everything I have gotten with DCRAW and Photoshop is worse than the in-camera JPGs.

So, for the moment I have reverted to shooting JPGs, but I would like to know the truth about this: For a normal, simple, straight, well exposed photo, is the JPG from the K-x really as good as it can get? That would be in conflict with those ubiquituous statements telling that the Pentax in-camera JPGs are no good. But IF it IS possible to get better quality by extrenally processing the raw files, then HOW EXACTLY is it done? It seems I would really need some sort of recipee: Which programs to use (hopefully free to use, or at least free to try), and how exactly to set each parameter, to get going. From there, I can experiment what works better, but with so many interacting parameters, and so little information of what the programs do with them, it seems almost impossible to get started in a good way, without such an instruction.

What I was expecting in the test shots was, very simply stated, seeing on the monitor something as closely similar as possible to the real thing I see out of the window. What's lacking to meet that goal is higher contrast, higher saturation, and correction of some specific hues (such as those tiny flowers, and such as the general green of the vegetation, which looks much too yellowish).
The problem is that when I simply crank up the contrast and saturation settings, I get more noise (grain) than what I would expect to get from a camera that has been as highly rated as the K-x. The grain I get is not tremendous! It's just about the same, or a little bit more, than that of my cheap point&shoot camera when it is delivering the required contrast and saturation. It's just that I expected the K-x to be significantly better than the little point&shoot bought four years ago! After all, one of the main advantages of having a "big" APS-sized sensor is supposed to be lower noise!

Those little red flowers in the distance did not saturate the red channel. Actually, the highest pixels in this photo are still well away from the saturation level. This photo could have been exposed a little higher before starting to saturate. So my guess is that the weak color of the flowers is simply because of the overall low contrast and saturation. It really looks like there is some flare happening. On subjects with general dark background, the K-x is performing fine, but with light backgrounds, it suffers this lack of saturation and contrast. It's not a lens problem. I tried all my lenses, and also the kit lens, and the contrast reduction is about the same with all. Just a little worse with the kit lens than with the Pentax A 50/1.4, or the Voigtlander 180/4 apochromatic lens, both of which are exceptionally good.

My monitor is indeed poorly calibrated, and not really capable of better performance. I don't have special calibration hardware, but I calibrated it internally to get the best possible overall response, using test charts I created myself, which contain color tables from zero to full saturation, and gray tables from full black to full white. So it's clear that with this monitor, I cannot expect to get an exact image of true life. So I'm comparing to images shot with the P&S camera, and to images coming from my slide scanner, and trying to discern what defect is due to the monitor, and what is due to the images coming from the K-x. In this matter, you comment about the image looking OK to you is very valuable!
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, contrast, cost, fog, image, image quality, k-x, pentax help, photography, photos, quality, sensor
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Please recommend a good multifunction ADF printer with good scanning quality raider General Talk 0 01-02-2010 07:03 PM
K or M Series - Which has the best image quality 8540tomg Pentax SLR Lens Discussion 20 10-05-2009 07:53 AM
K-7 image quality concern claude21 Pentax DSLR Discussion 31 06-26-2009 11:34 AM
What you care more on shopping digital camera, good quality or or good looking? emilyy General Talk 19 12-12-2008 07:35 PM
DA 16-45mm image quality sveinmb Pentax SLR Lens Discussion 25 09-18-2008 03:58 PM



All times are GMT -7. The time now is 05:14 AM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top