White spots in the sky

JeffJS · 06-06-2011, 05:27 AM

Originally posted by peasant

No,mine are more a pale grey but it was overcast here all day.Nothing for me at f5.6.

Yours are probably dust.

https://www.pentaxforums.com/forums/pentax-dslr-camera-articles/121739-those-...ml#post1259109

peasant · 06-06-2011, 05:41 AM

Originally posted by JeffJS

Yours are probably dust.

Thank you,I hope you are correct,any reason the spots would be visible at smaller apertures and not at larger apertures?

JeffJS · 06-06-2011, 05:50 AM

Originally posted by peasant

Thank you,I hope you are correct,any reason the spots would be visible at smaller apertures and not at larger apertures?

I don't know the exact scientific answer but it is basically the Depth of Field of your photo. More is in focus at the smaller apertures than the large ones. You are not seeing dust ON the sensor but rather the filter screen just in front of it. If it were On the sensor, it would show up in all photos and would probably Be White (I don't think that's the issue of the OP however because the spots are not always there and they move). As it is, you are getting an actual photo Of the dust, hair, slime, ect. Whatever happens to be on the sensor filter. The greater your DOF, the more sharp it will show. It's still there at larger apertures but is so out of focus, you cannot really see it.

peasant · 06-06-2011, 06:17 AM

Originally posted by JeffJS

It's still there at larger apertures but is so out of focus, you cannot really see it.

Once again thanks,what you say makes sense but there are still a few variables I'd like to check out.

Ducatigaz · 06-08-2011, 05:45 AM

I had a similar problem last summer with a K20D .It was a hot sunny day by a lake ,it was small pieces of blossom/seeds floating around in the sky

hjb981 · 06-08-2011, 05:59 AM

The white spots in the first post looks very similar to something I saw in a picture I took of some jet tracks on a clear blue sky. That one picture is the only time I have ever seen it (in about 2000 pictures so far, including others with blue sky at least in parts of the pictures). I only saw it afterwards, so I could not check for explanations (like stuff in the air etc) where the picture was taken. I used the DA 18-135 WR, but I do not know at what settings (the picture is not on the computer I am writing on). Of course it could have been something in the air - hard to check that afterwards...

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06-06-2011, 05:27 AM	#16
JeffJS Inactive Account Join Date: Aug 2008 Location: Michigan, USA Photos: Gallery \| Albums Posts: 7,484	Originally posted by peasant No,mine are more a pale grey but it was overcast here all day.Nothing for me at f5.6. Yours are probably dust. https://www.pentaxforums.com/forums/pentax-dslr-camera-articles/121739-those-...ml#post1259109

06-06-2011, 05:41 AM	#17
peasant Forum Member Join Date: Aug 2009 Location: adelaide Photos: Albums Posts: 89	Originally posted by JeffJS Yours are probably dust. Thank you,I hope you are correct,any reason the spots would be visible at smaller apertures and not at larger apertures?

06-06-2011, 05:50 AM	#18
JeffJS Inactive Account Join Date: Aug 2008 Location: Michigan, USA Photos: Gallery \| Albums Posts: 7,484	Originally posted by peasant Thank you,I hope you are correct,any reason the spots would be visible at smaller apertures and not at larger apertures? I don't know the exact scientific answer but it is basically the Depth of Field of your photo. More is in focus at the smaller apertures than the large ones. You are not seeing dust ON the sensor but rather the filter screen just in front of it. If it were On the sensor, it would show up in all photos and would probably Be White (I don't think that's the issue of the OP however because the spots are not always there and they move). As it is, you are getting an actual photo Of the dust, hair, slime, ect. Whatever happens to be on the sensor filter. The greater your DOF, the more sharp it will show. It's still there at larger apertures but is so out of focus, you cannot really see it.

06-06-2011, 06:17 AM	#19
peasant Forum Member Join Date: Aug 2009 Location: adelaide Photos: Albums Posts: 89	Originally posted by JeffJS It's still there at larger apertures but is so out of focus, you cannot really see it. Once again thanks,what you say makes sense but there are still a few variables I'd like to check out.

06-08-2011, 05:45 AM	#20
Ducatigaz Pentaxian Join Date: Feb 2010 Location: Blunsdon,Wiltshire, UK Posts: 1,502	I had a similar problem last summer with a K20D .It was a hot sunny day by a lake ,it was small pieces of blossom/seeds floating around in the sky

06-08-2011, 05:59 AM	#21
hjb981 Forum Member Join Date: Apr 2011 Posts: 71	The white spots in the first post looks very similar to something I saw in a picture I took of some jet tracks on a clear blue sky. That one picture is the only time I have ever seen it (in about 2000 pictures so far, including others with blue sky at least in parts of the pictures). I only saw it afterwards, so I could not check for explanations (like stuff in the air etc) where the picture was taken. I used the DA 18-135 WR, but I do not know at what settings (the picture is not on the computer I am writing on). Of course it could have been something in the air - hard to check that afterwards...