pentax k-x sensor problem

mRo · 12-09-2009, 12:38 PM

Hi,

recently i bought pentax kx with kit lens 18-55mm smc DAL. My problem lies with P and autoPict mode. I know that dslr's arent supposed to be p&s cameras, but it's annoying not to have auto options.

Now the problem:
If i set it to P or AutoPict on indoors with normal (not dark, not bright) lighting with flash on i never get shutter speeds above 1/20 or 1/30, and it likes to go as slow as 1/8. Now my logic tells me if light is so low than it really doesn't make any difference between 1/8 and 1/80 since flash is the only light that will get on the picture. Only problem si that 1/8 will produce blurry images, and 1/80 will produce normal image. So, is this normal behavior for k-x's or is something wrong with body/sensor. I tried to update to firmware 1.01 but nothing changed.

I looked this with other cameras and they mostly have shutter speeds locked to 1/80 or something like that which is normal in my opinion.

And yes, i forgot to mention, aperture is always set to fully open.

P.S. sorry for my english, is't been a while since i used it

Best regards, Marko from Croatia

Marc Sabatella · 12-09-2009, 12:56 PM

Hello, and welcome!

I'd assume the camera is trying to balance the flash with ambient light, and is thinking that even with those slow shutter speeds, there won't be so much ambient light that you get blurry pictures. Either that, or something else you have set - like if you have your ISO turned way way up - is making the camera think that you do want to get more ambient light in there. Could you post a picture and tells us what ISO, aperture, and shutter speed were used?

audiobomber · 12-09-2009, 01:32 PM

Auto ISO gives all kinds of whacky results. The only success I've had is when I manually set the aperture and ISO.

bnorikane · 12-10-2009, 07:47 AM

Hi Marko,

That is normal behavior, not a defect. I've seen the same on my K-x.

The kind folk here have explained the auto-exposure with flash to me. Pentax cameras set the minimum shutter speed to the steady handhold limit. With SR on, that's a bit slower than 1/FL. With your 18-55 zoomed to 18mm, in P mode, the slowest shutter should be 1/15s. The Kx does not adjust the limit up with SR off, which it probably should.

I only get slower shutters when I turn the e-dial to get a smaller aperture for greater depth of field. I have seen 1/8s when I close down the aperture.

I use Tv or M mode with flash now, when I want to prevent blur. The flash will automatically adjust to expose the subject in M or Tv. In Tv, auto-iso will also work.

Last edited by bnorikane; 12-10-2009 at 08:02 AM.

mRo · 12-10-2009, 11:05 AM

Didn't have time to take some new pics, but one more thing i forgot to mention, White balance doesn't work either. On M or P mode i select tungsten light and take picture, but resulting picture has AWB not tungsten light. Whatever white balance i select it always says AWB and ofcourse colors don't match with selected WB. I use JPEG, not RAW or RAW+.

audiobomber · 12-10-2009, 11:19 AM

Originally posted by mRo

Didn't have time to take some new pics, but one more thing i forgot to mention, White balance doesn't work either. On M or P mode i select tungsten light and take picture, but resulting picture has AWB not tungsten light. Whatever white balance i select it always says AWB and ofcourse colors don't match with selected WB. I use JPEG, not RAW or RAW+.

You can't make some changes in Green mode or auto picture modes. Try shooting in P mode, it is an auto mode, but allows user control.

mRo · 12-10-2009, 11:22 AM

I know, i tried to make changes in P and in M mode and when i choose it shows it on the screen as being selected, but when i take picture, on the picture info it says AWB (and as i said earlier colors don't match with selection, so i know for sure it's AWB)

**Ash** · 12-10-2009, 11:30 AM

You should have no trouble choosing your own WB on P, Av, Tv, and M modes on the camera.
Try it again with a non-auto mode and see how the shutter speed and WB behaves.

mRo · 12-10-2009, 12:21 PM

Sorry, my bad, i found option that AWB was linked with flash. But slow shutter problem persists

**Ash** · 12-10-2009, 02:32 PM

Try Av mode - does the shutter speed go slower than 1/(focal length)?

bnorikane · 12-10-2009, 05:17 PM

Marko,

As you found, with flash on, camera will use the WB that you set in menu C-2-8 "WB when using Flash". Default is AWB, but you can change it to use your set WB or Flash WB.

In Auto Pict/green mode, the camera forces AWB.

In other modes, PASM without flash, the camera will use what you set.

bnorikane · 12-10-2009, 05:35 PM

Originally posted by mRo

But slow shutter problem persists

Try Tv or M with flash.

I fought this for awhile, but it's really easy. The camera will auto adjust flash power (and ISO if in auto iso) to get the exposure right.

For example, in M set shutter to 1/80 and A to f/8, auto-iso and flash up. Just snap away.

Try it, you may like it.

12-09-2009, 12:38 PM	#1
mRo New Member Join Date: Dec 2009 Location: Zagreb Posts: 4	pentax k-x sensor problem Hi, recently i bought pentax kx with kit lens 18-55mm smc DAL. My problem lies with P and autoPict mode. I know that dslr's arent supposed to be p&s cameras, but it's annoying not to have auto options. Now the problem: If i set it to P or AutoPict on indoors with normal (not dark, not bright) lighting with flash on i never get shutter speeds above 1/20 or 1/30, and it likes to go as slow as 1/8. Now my logic tells me if light is so low than it really doesn't make any difference between 1/8 and 1/80 since flash is the only light that will get on the picture. Only problem si that 1/8 will produce blurry images, and 1/80 will produce normal image. So, is this normal behavior for k-x's or is something wrong with body/sensor. I tried to update to firmware 1.01 but nothing changed. I looked this with other cameras and they mostly have shutter speeds locked to 1/80 or something like that which is normal in my opinion. And yes, i forgot to mention, aperture is always set to fully open. P.S. sorry for my english, is't been a while since i used it Best regards, Marko from Croatia

12-10-2009, 12:21 PM	#9
mRo New Member Join Date: Dec 2009 Location: Zagreb Posts: 4 Original Poster	Sorry, my bad, i found option that AWB was linked with flash. But slow shutter problem persists Last edited by mRo; 12-11-2009 at 01:17 AM.

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12-09-2009, 12:56 PM	#2
Marc Sabatella Veteran Member Join Date: Sep 2006 Location: Denver, CO Photos: Gallery Posts: 10,685	Hello, and welcome! I'd assume the camera is trying to balance the flash with ambient light, and is thinking that even with those slow shutter speeds, there won't be so much ambient light that you get blurry pictures. Either that, or something else you have set - like if you have your ISO turned way way up - is making the camera think that you do want to get more ambient light in there. Could you post a picture and tells us what ISO, aperture, and shutter speed were used?

12-09-2009, 01:32 PM	#3
audiobomber Veteran Member Join Date: May 2008 Location: Sudbury, Ontario Photos: Albums Posts: 6,806	Auto ISO gives all kinds of whacky results. The only success I've had is when I manually set the aperture and ISO.

12-10-2009, 07:47 AM	#4
bnorikane Forum Member Join Date: Oct 2009 Location: Colorado Photos: Albums Posts: 91	Hi Marko, That is normal behavior, not a defect. I've seen the same on my K-x. The kind folk here have explained the auto-exposure with flash to me. Pentax cameras set the minimum shutter speed to the steady handhold limit. With SR on, that's a bit slower than 1/FL. With your 18-55 zoomed to 18mm, in P mode, the slowest shutter should be 1/15s. The Kx does not adjust the limit up with SR off, which it probably should. I only get slower shutters when I turn the e-dial to get a smaller aperture for greater depth of field. I have seen 1/8s when I close down the aperture. I use Tv or M mode with flash now, when I want to prevent blur. The flash will automatically adjust to expose the subject in M or Tv. In Tv, auto-iso will also work. Last edited by bnorikane; 12-10-2009 at 08:02 AM.

12-10-2009, 11:05 AM	#5
mRo New Member Join Date: Dec 2009 Location: Zagreb Posts: 4 Original Poster	Didn't have time to take some new pics, but one more thing i forgot to mention, White balance doesn't work either. On M or P mode i select tungsten light and take picture, but resulting picture has AWB not tungsten light. Whatever white balance i select it always says AWB and ofcourse colors don't match with selected WB. I use JPEG, not RAW or RAW+.

12-10-2009, 11:19 AM	#6
audiobomber Veteran Member Join Date: May 2008 Location: Sudbury, Ontario Photos: Albums Posts: 6,806	Originally posted by mRo Didn't have time to take some new pics, but one more thing i forgot to mention, White balance doesn't work either. On M or P mode i select tungsten light and take picture, but resulting picture has AWB not tungsten light. Whatever white balance i select it always says AWB and ofcourse colors don't match with selected WB. I use JPEG, not RAW or RAW+. You can't make some changes in Green mode or auto picture modes. Try shooting in P mode, it is an auto mode, but allows user control.

12-10-2009, 11:22 AM	#7
mRo New Member Join Date: Dec 2009 Location: Zagreb Posts: 4 Original Poster	I know, i tried to make changes in P and in M mode and when i choose it shows it on the screen as being selected, but when i take picture, on the picture info it says AWB (and as i said earlier colors don't match with selection, so i know for sure it's AWB)

12-10-2009, 11:30 AM	#8
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	You should have no trouble choosing your own WB on P, Av, Tv, and M modes on the camera. Try it again with a non-auto mode and see how the shutter speed and WB behaves.

12-10-2009, 02:32 PM	#10
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Try Av mode - does the shutter speed go slower than 1/(focal length)?

12-10-2009, 05:17 PM	#11
bnorikane Forum Member Join Date: Oct 2009 Location: Colorado Photos: Albums Posts: 91	Marko, As you found, with flash on, camera will use the WB that you set in menu C-2-8 "WB when using Flash". Default is AWB, but you can change it to use your set WB or Flash WB. In Auto Pict/green mode, the camera forces AWB. In other modes, PASM without flash, the camera will use what you set.

12-10-2009, 05:35 PM	#12
bnorikane Forum Member Join Date: Oct 2009 Location: Colorado Photos: Albums Posts: 91	Originally posted by mRo But slow shutter problem persists Try Tv or M with flash. I fought this for awhile, but it's really easy. The camera will auto adjust flash power (and ISO if in auto iso) to get the exposure right. For example, in M set shutter to 1/80 and A to f/8, auto-iso and flash up. Just snap away. Try it, you may like it.