Pentax K-X images with noise

Brutanox · 05-23-2020, 03:29 PM

Hello. I am a new owner of a second hand Pentax KX. The camera seems to work very well, but all my images are with noise (pixels) even at low ISO and are not very sharp (the photos look like were made with a 20 year old phone VGA camera). I tried every setting on and off, i tried different scenes and programs. Nothing. Only HDR ON seems to do something better, but still far away. My phone on auto is doing a lot better than this DSLR. I read a lot of good things about the KX and i think i am doing something wrong. Can you help me with some settings or advice? Maybe I am missing something. I am a beginner, i shot JPEGs right now.

I attached 2 photos, the ugly one shot with the KX (the best i could...) and the good one shot with phone in a hurry.

Attached Images

View Picture EXIF

Parallax · 05-23-2020, 03:39 PM

Originally posted by Brutanox

even at low ISO and are not very sharp

The EXIF shows that the top photo was shot at 6400 ISO. That is not "low ISO". It's quite high and I would certainly expect to see noise.
Now, having said that, I don't see a sharpness problem. I see a distinct midtone contrast difference between the two pictures. A curves adjustment would go a long way towards correcting that.
You didn't say what your jpeg settings are.

Brutanox · 05-23-2020, 04:02 PM

What the...6400?! You are right. How the hell got to max? It was on "auto mode". In pentamirror was 800 or so (auto), so i was sure it was low, didn't even check. What did i do wrong? And why does auto set the iso to max level?

Brutanox · 05-23-2020, 04:10 PM

Forgot the jpeg settings. 12 mp, 3 star (max detail). These are the ones i leave alone. The other i try to modify and explore. In the photo uploaded I don't know what was set. Please recommend something to try.

**luftfluss** · 05-23-2020, 04:20 PM - **1 Like**

As @Parallax suggested, a midtone contrast boost (and a bit of noise reduction) does wonders.

It's been a while since I had a K-x, but there might be settings to adjust the JPEG files so the output is more to your liking.

Sandy Hancock · 05-23-2020, 04:21 PM - **1 Like**

You're shooting with a slowish lens in lowish light, so the camera's shooting mode will max out the ISO to keep to the shutter speed manageable.

Spot metering might be part of the problem too. It might have metered off the white of the panda (right in the middle of the frame), leaving the rest of the image relatively underexposed. The camera's JPEG engine will then apply aggressive shadow correction, which also adds noise. I would avoid spot metering for all but very specific situations - like spotlit stage performers or strongly backlit subjects.

The tiny sensor of your phone allows the use of lenses with tiny focal lengths, which gives massive depth of field even at relatively wide apertures. To get the same depth with a 55mm lens would require stopping down to maybe f/11 or smaller, which in that light would necessitate a tripod.

Sandy Hancock · 05-23-2020, 04:33 PM

Originally posted by Brutanox

Please recommend something to try.

Put the camera into Av mode and matrix metering. Set your lens to f/11 and the focal length to match the field of view of your phone (somewhere around 20mm I suspect). Set your ISO at 100. Turn on the 2 second shutter delay, put the camera on a tripod, and focus carefully.

The resultant JPEG should be *much* better than anything your phone can do.

**mikesbike** · 05-23-2020, 07:08 PM

Originally posted by Sandy Hancock

Spot metering might be part of the problem too. It might have metered off the white of the panda (right in the middle of the frame), leaving the rest of the image relatively underexposed.

Definitely. Best not to use the spot metering until you learn how and when to employ it. Use the matrix/segmented metering (the usual by default). Underexposure also will to a greater degree reveal the noise/grain "pixels" you are seeing, which are the result of using such a high ISO.

The reason Sandy recommends using a tripod is he also recommends using f/11, which is setting your aperture to a narrower value (larger number means smaller aperture), which lets in less light so your shutter speed will have to be quite slow to compensate, too slow for hand-held shooting without blur from the body's slight motion. The reason for this compromise of f/11 and less incoming light is a smaller aperture also increases depth-of-field (DOF) meaning more of what is in the background and foreground of your shot will be sharp in addition to your main subject.

Putting your camera's AF sensors to center-only spot AF will give you the ability to train focus more accurately where you want it to be. Use the half-press of the shutter button to achieve and hold your focus, then press the rest of the way to fire the shot.

Don't have your camera's mode dial on the green "auto" mode, as this will disallow making most adjustments. Use the P (Program) mode for your fully automatic exposure setting, or for aperture control use Av as Sandy suggests.

The K-x probably has Custom Image settings. Default will be in the "Bright" category. Access its menu and tab down to the bottom Sharpness department, then using your rear thumb dial I believe, add "F"- for "Fine Sharpening".

The moderate adjustments luftfuss has made to your image gives you a good idea of what your camera actually delivered, even though not having an ideal setup.

Getting back to the narrower aperture and greater DOF, from this you can see that controlling DOF by controlling aperture is often an important factor that your phone cannot do. By using this same control of DOF, by your own choice you can use a larger aperture to deliberately reduce DOF so your subject will be sharper than surrounding objects, and will thus better stand out in your composition. Your choice and your control.

**lsimpkins** · 05-25-2020, 09:29 AM

One other thing to remember is that your K-X was introduced in 2009. I doubt that your phone is that old. The amount of processing that modern cell phones apply to their images probably wasn't even thought of in 2009.
So, in addition to the camera settings that have already been mentioned, you may need to apply considerable software adjustments to the K-X images to get near what the phone produces. And as the image sensor itself is probably several generations behind what is in your phone, even software may not be enough to produce comparable or better images from the camera.

05-23-2020, 04:20 PM - 1 Like	#5
luftfluss Site Supporter Join Date: Jun 2011 Location: NJ Photos: Gallery \| Albums Posts: 11,629	As @Parallax suggested, a midtone contrast boost (and a bit of noise reduction) does wonders. It's been a while since I had a K-x, but there might be settings to adjust the JPEG files so the output is more to your liking. Attached Images

05-23-2020, 07:08 PM	#8
mikesbike Site Supporter Join Date: Dec 2016 Location: Southeastern Michigan Posts: 4,566	Originally posted by Sandy Hancock Spot metering might be part of the problem too. It might have metered off the white of the panda (right in the middle of the frame), leaving the rest of the image relatively underexposed. Definitely. Best not to use the spot metering until you learn how and when to employ it. Use the matrix/segmented metering (the usual by default). Underexposure also will to a greater degree reveal the noise/grain "pixels" you are seeing, which are the result of using such a high ISO. The reason Sandy recommends using a tripod is he also recommends using f/11, which is setting your aperture to a narrower value (larger number means smaller aperture), which lets in less light so your shutter speed will have to be quite slow to compensate, too slow for hand-held shooting without blur from the body's slight motion. The reason for this compromise of f/11 and less incoming light is a smaller aperture also increases depth-of-field (DOF) meaning more of what is in the background and foreground of your shot will be sharp in addition to your main subject. Putting your camera's AF sensors to center-only spot AF will give you the ability to train focus more accurately where you want it to be. Use the half-press of the shutter button to achieve and hold your focus, then press the rest of the way to fire the shot. Don't have your camera's mode dial on the green "auto" mode, as this will disallow making most adjustments. Use the P (Program) mode for your fully automatic exposure setting, or for aperture control use Av as Sandy suggests. The K-x probably has Custom Image settings. Default will be in the "Bright" category. Access its menu and tab down to the bottom Sharpness department, then using your rear thumb dial I believe, add "F"- for "Fine Sharpening". The moderate adjustments luftfuss has made to your image gives you a good idea of what your camera actually delivered, even though not having an ideal setup. Getting back to the narrower aperture and greater DOF, from this you can see that controlling DOF by controlling aperture is often an important factor that your phone cannot do. By using this same control of DOF, by your own choice you can use a larger aperture to deliberately reduce DOF so your subject will be sharper than surrounding objects, and will thus better stand out in your composition. Your choice and your control. Last edited by mikesbike; 05-23-2020 at 07:23 PM.

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05-23-2020, 03:39 PM	#2
Parallax Senior Moderator Loyal Site Supporter Join Date: Apr 2008 Location: South Dakota Photos: Gallery Posts: 19,333	Originally posted by Brutanox even at low ISO and are not very sharp The EXIF shows that the top photo was shot at 6400 ISO. That is not "low ISO". It's quite high and I would certainly expect to see noise. Now, having said that, I don't see a sharpness problem. I see a distinct midtone contrast difference between the two pictures. A curves adjustment would go a long way towards correcting that. You didn't say what your jpeg settings are.

05-23-2020, 04:02 PM	#3
Brutanox New Member Join Date: May 2020 Posts: 3 Original Poster	What the...6400?! You are right. How the hell got to max? It was on "auto mode". In pentamirror was 800 or so (auto), so i was sure it was low, didn't even check. What did i do wrong? And why does auto set the iso to max level?

05-23-2020, 04:10 PM	#4
Brutanox New Member Join Date: May 2020 Posts: 3 Original Poster	Forgot the jpeg settings. 12 mp, 3 star (max detail). These are the ones i leave alone. The other i try to modify and explore. In the photo uploaded I don't know what was set. Please recommend something to try.

05-23-2020, 04:21 PM - 1 Like	#6
Sandy Hancock Moderator Site Supporter Join Date: Feb 2012 Location: Adelaide Hills, South Australia Photos: Gallery \| Albums Posts: 11,276	You're shooting with a slowish lens in lowish light, so the camera's shooting mode will max out the ISO to keep to the shutter speed manageable. Spot metering might be part of the problem too. It might have metered off the white of the panda (right in the middle of the frame), leaving the rest of the image relatively underexposed. The camera's JPEG engine will then apply aggressive shadow correction, which also adds noise. I would avoid spot metering for all but very specific situations - like spotlit stage performers or strongly backlit subjects. The tiny sensor of your phone allows the use of lenses with tiny focal lengths, which gives massive depth of field even at relatively wide apertures. To get the same depth with a 55mm lens would require stopping down to maybe f/11 or smaller, which in that light would necessitate a tripod.

05-23-2020, 04:33 PM	#7
Sandy Hancock Moderator Site Supporter Join Date: Feb 2012 Location: Adelaide Hills, South Australia Photos: Gallery \| Albums Posts: 11,276	Originally posted by Brutanox Please recommend something to try. Put the camera into Av mode and matrix metering. Set your lens to f/11 and the focal length to match the field of view of your phone (somewhere around 20mm I suspect). Set your ISO at 100. Turn on the 2 second shutter delay, put the camera on a tripod, and focus carefully. The resultant JPEG should be much better than anything your phone can do.

05-25-2020, 09:29 AM	#9
lsimpkins Site Supporter Join Date: Feb 2013 Location: SE Pennsylvania Photos: Gallery \| Albums Posts: 544	One other thing to remember is that your K-X was introduced in 2009. I doubt that your phone is that old. The amount of processing that modern cell phones apply to their images probably wasn't even thought of in 2009. So, in addition to the camera settings that have already been mentioned, you may need to apply considerable software adjustments to the K-X images to get near what the phone produces. And as the image sensor itself is probably several generations behind what is in your phone, even software may not be enough to produce comparable or better images from the camera.