DUST MAPPING IS CLEAN - but still specks on my photos - what's up??

slr_neophyte · 07-17-2011, 04:07 AM

Looking for a bit of quick advice here - I'm out of town traveling and forgot my cleaning kit at home. These annoying specks have been showing up on my photos and my lenses are clean, AND the dust mapping check function on my K-x also shows CLEAN - I can't see anything. That should suggest that my sensor is clean, should it not?? I've attached a few photos for all to see. I will see if I can get a blower somewhere tomorrow and try that - hopefully that works. However if it's not the sensor then I'm not really sure what it could be.

Last edited by slr_neophyte; 12-14-2012 at 08:54 PM.

twitch · 07-17-2011, 04:16 AM

You have dust on your sensor, the dust detect feature is worthless, ignor it.

Docrwm · 07-17-2011, 05:40 AM

You need a blower because you have dust on your sensor.

photolady95 · 07-17-2011, 05:53 AM

Originally posted by twitch

dust detect feature is worthless

I'll second that. On my K-x, as new, I tried that gadget and I still could see dust on my photos. Got my Giottos out, blew in a few times, dust gone.

epqwerty · 07-17-2011, 05:55 AM - **1 Like**

Reclean still dirty.

As for the dust alert it is not useless. It isnt always accurate and really deends on how you use it. I always find that t works best with a clean solid surface that is of one colour. Anything that is rough texture can confuse the function of it. And also running it twice for confirmation is best i think.

**ramseybuckeye** · 07-17-2011, 06:57 PM

Originally posted by epqwerty

Reclean still dirty.

As for the dust alert it is not useless. It isnt always accurate and really deends on how you use it. I always find that t works best with a clean solid surface that is of one colour. Anything that is rough texture can confuse the function of it. And also running it twice for confirmation is best i think.

I second that. it works very well if you have a good target. I use a blank white word processing page on my computer screen, nice and bright white.

Elva · 07-17-2011, 11:57 PM

I have had similar problems where the dust detect failed to pick up the dust and a blower did the trick. I used the sky as a test. As there was nothing for the autofocus to focus on I set the lens to infinity and took a photo of the sky. Cleaned the sensor and did a re check, used my PC to do the check for the dust speck.

Docrwm · 07-18-2011, 04:57 AM

Originally posted by Elva

I have had similar problems where the dust detect failed to pick up the dust and a blower did the trick. I used the sky as a test. As there was nothing for the autofocus to focus on I set the lens to infinity and took a photo of the sky. Cleaned the sensor and did a re check, used my PC to do the check for the dust speck.

Doesn't it also help to set the Aperture to maximum?

agsy · 07-18-2011, 02:14 PM

Originally posted by Elva

I have had similar problems where the dust detect failed to pick up the dust and a blower did the trick. I used the sky as a test. As there was nothing for the autofocus to focus on I set the lens to infinity and took a photo of the sky. Cleaned the sensor and did a re check, used my PC to do the check for the dust speck.

I second that. The "sky test" works best because it is a practical image showing the real time result. I usually set my aperture to f13, manual focus to past infinity,set the lens to 50mm and shoot away. Once you have the photo downloaded, it helps to boost the contrast way up to really see the dust (I use Picasa and slide the "shadows" bar all the way up). Just remember, the photo you are looking at is flipped, so if the dust shows on the right upper corner, it's really in the lower left.

Jean Poitiers · 07-18-2011, 02:57 PM

The sky test works great for me, too ... around f11 + at infinity, manual focus.

twitch · 07-18-2011, 03:16 PM

Usually for sky test I focus at closest distance, and for wall test I focus at infinity. I also use f22, ISO100, and wave the camera around a bit if it's a long shutter speed. I want to eliminate any possbility of whats in the sky, or what on the wall showing up in my photos. PRoblem is if you focus at infinity at the sky you will focus at what's in the sky (eg birds).

I then import the photo(s), flip it vertically (so if spot is top left in photo, it's top left looking at the sensor with the camera facing me), and then do an auto levels to highlight the spots clearly. Do all this, and even the subtlest spots of dust will be seen and you'll know exactly where they are on the sensor (handy if using Pentax lollipop).

**dadipentak** · 07-18-2011, 03:47 PM

Originally posted by twitch

the dust detect feature is worthless,

pretty much

07-17-2011, 04:07 AM	#1
slr_neophyte Senior Member Join Date: Aug 2010 Location: Suzhou China Photos: Gallery Posts: 149	DUST MAPPING IS CLEAN - but still specks on my photos - what's up?? Looking for a bit of quick advice here - I'm out of town traveling and forgot my cleaning kit at home. These annoying specks have been showing up on my photos and my lenses are clean, AND the dust mapping check function on my K-x also shows CLEAN - I can't see anything. That should suggest that my sensor is clean, should it not?? I've attached a few photos for all to see. I will see if I can get a blower somewhere tomorrow and try that - hopefully that works. However if it's not the sensor then I'm not really sure what it could be. Last edited by slr_neophyte; 12-14-2012 at 08:54 PM.

07-18-2011, 02:14 PM	#9
agsy Veteran Member Join Date: Aug 2010 Location: Florida Photos: Gallery \| Albums Posts: 551	Originally posted by Elva I have had similar problems where the dust detect failed to pick up the dust and a blower did the trick. I used the sky as a test. As there was nothing for the autofocus to focus on I set the lens to infinity and took a photo of the sky. Cleaned the sensor and did a re check, used my PC to do the check for the dust speck. I second that. The "sky test" works best because it is a practical image showing the real time result. I usually set my aperture to f13, manual focus to past infinity,set the lens to 50mm and shoot away. Once you have the photo downloaded, it helps to boost the contrast way up to really see the dust (I use Picasa and slide the "shadows" bar all the way up). Just remember, the photo you are looking at is flipped, so if the dust shows on the right upper corner, it's really in the lower left. Last edited by agsy; 07-18-2011 at 03:02 PM.

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07-17-2011, 04:16 AM	#2
twitch Veteran Member Join Date: Nov 2009 Posts: 4,571	You have dust on your sensor, the dust detect feature is worthless, ignor it.

07-17-2011, 05:40 AM	#3
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285	You need a blower because you have dust on your sensor.

07-17-2011, 05:53 AM	#4
photolady95 Otis Memorial Pentaxian Join Date: May 2009 Location: Cruising the forum watching his back Photos: Gallery \| Albums Posts: 12,712	Originally posted by twitch dust detect feature is worthless I'll second that. On my K-x, as new, I tried that gadget and I still could see dust on my photos. Got my Giottos out, blew in a few times, dust gone.

07-17-2011, 05:55 AM - 1 Like	#5
epqwerty Veteran Member Join Date: Dec 2009 Location: Ontario Posts: 550	Reclean still dirty. As for the dust alert it is not useless. It isnt always accurate and really deends on how you use it. I always find that t works best with a clean solid surface that is of one colour. Anything that is rough texture can confuse the function of it. And also running it twice for confirmation is best i think.

07-17-2011, 06:57 PM	#6
ramseybuckeye Site Supporter Join Date: Apr 2009 Location: Hampstead, NC Photos: Gallery Posts: 17,291	Originally posted by epqwerty Reclean still dirty. As for the dust alert it is not useless. It isnt always accurate and really deends on how you use it. I always find that t works best with a clean solid surface that is of one colour. Anything that is rough texture can confuse the function of it. And also running it twice for confirmation is best i think. I second that. it works very well if you have a good target. I use a blank white word processing page on my computer screen, nice and bright white.

07-17-2011, 11:57 PM	#7
Elva Senior Member Join Date: Sep 2009 Location: Grahamstown in the Eastern Cape province of South Africa Photos: Gallery Posts: 125	I have had similar problems where the dust detect failed to pick up the dust and a blower did the trick. I used the sky as a test. As there was nothing for the autofocus to focus on I set the lens to infinity and took a photo of the sky. Cleaned the sensor and did a re check, used my PC to do the check for the dust speck.

07-18-2011, 04:57 AM	#8
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285	Originally posted by Elva I have had similar problems where the dust detect failed to pick up the dust and a blower did the trick. I used the sky as a test. As there was nothing for the autofocus to focus on I set the lens to infinity and took a photo of the sky. Cleaned the sensor and did a re check, used my PC to do the check for the dust speck. Doesn't it also help to set the Aperture to maximum?

07-18-2011, 02:57 PM	#10
Jean Poitiers Pentaxian Join Date: Apr 2011 Location: Lost in translation ... Photos: Gallery \| Albums Posts: 18,076	The sky test works great for me, too ... around f11 + at infinity, manual focus.

07-18-2011, 03:16 PM	#11
twitch Veteran Member Join Date: Nov 2009 Posts: 4,571	Usually for sky test I focus at closest distance, and for wall test I focus at infinity. I also use f22, ISO100, and wave the camera around a bit if it's a long shutter speed. I want to eliminate any possbility of whats in the sky, or what on the wall showing up in my photos. PRoblem is if you focus at infinity at the sky you will focus at what's in the sky (eg birds). I then import the photo(s), flip it vertically (so if spot is top left in photo, it's top left looking at the sensor with the camera facing me), and then do an auto levels to highlight the spots clearly. Do all this, and even the subtlest spots of dust will be seen and you'll know exactly where they are on the sensor (handy if using Pentax lollipop).

07-18-2011, 03:47 PM	#12
dadipentak Site Supporter Join Date: Jul 2008 Location: Baltimore, Maryland Photos: Gallery Posts: 11,590	Originally posted by twitch the dust detect feature is worthless, pretty much