K20D sensor artifacts?

Adam_T4 · 12-19-2009, 12:09 PM

Hi Guys,
Fairly new Pentax owner here with what appear to be night-shot sensor artifacts. I don't think it is lens flair. Shot on a Pentax K20D with a FA 50mm 1.4 lens wide open @ 1/25 of a second, ISO 1600, EV 0. I had read about some long exposure hot pixel issues with this camera before I got it, and had concerns, but these are new to me. Any opinions about them, fellow Pentax users?
My flickr page Flickr: Adam_T4's Photostream

Attached Images

**Ash** · 12-19-2009, 12:17 PM

These don't look artifactual - they look real.
These are not what hot pixels look like.
During the exposure you never noticed a light-emitting object falling/rising within the scene forming the curve at left?

Adam_T4 · 12-19-2009, 12:26 PM

I really didn't see any light source where that arc is. My attention was on the London Eye entirely at the time.

RBellavance · 12-19-2009, 12:34 PM

Interesting... I don't think it can be a rising/falling object because the exposure time was 1/25s.

Do you have a filter in front of the lens ? My only guess would be flare/reflection from it.

**davidreilly3207** · 12-19-2009, 12:44 PM

Definitely a reflection, if not from a filter, then off the back glass of the lens itself.

glanglois · 12-19-2009, 12:55 PM

If that was taken from just above Westminster Pier, I may have some that I can compare to yours except for the lens.

**Ash** · 12-19-2009, 01:02 PM

Ah, indeed - the arc of the 'artifact' mirrors that of the ferris wheel.

glanglois · 12-19-2009, 01:14 PM

Originally posted by Ash

Ah, indeed - the arc of the 'artifact' mirrors that of the ferris wheel.

The dots resemble the dots/streak in my images that I believe to be aircraft in, I think, the Heathrow pattern.

The arc, though, is either a reflection or something from the Sontarans or the Shadow Proclamation.

The photo was taken from Westminster Bridge? The angle seems off for Westminster Pier. Alas, I'm a too-occasional visitor and may have my geography mis-remembered.

Oggy · 12-19-2009, 03:06 PM

The three dots look like part of the Ursa Major constellation to me.

glanglois · 12-19-2009, 03:47 PM

Originally posted by Oggy

The three dots look like part of the Ursa Major constellation to me.

I'm almost hesitant to ask about the anatomy of the bear ....

Adam_T4 · 12-19-2009, 03:52 PM

London is very well lit up at night, I doubt any constellations were visable. I'm going with an internal reflection, as I did have a UV filter on the lens. This would be the first time I've come across a reason to not use any filters. Thanks for the replies.

KungPOW · 12-19-2009, 04:34 PM

I concore with the others.

You have filter reflection there.

Always remove your UV filter for night shots.

Also, stop the lens down for night shots to get sharp stars at the bright light points instead of the fuzzy blobs.

raz-0 · 12-19-2009, 04:41 PM

Internal reflections of the lights on the wheel (the side out of frame), and the more horizontal string are reflections from the lights on the boardwalk/midway/whatever.

It's not the sensor.

12-19-2009, 12:09 PM	#1
Adam_T4 Forum Member Join Date: Aug 2009 Location: NYC Photos: Gallery Posts: 51	K20D sensor artifacts? Hi Guys, Fairly new Pentax owner here with what appear to be night-shot sensor artifacts. I don't think it is lens flair. Shot on a Pentax K20D with a FA 50mm 1.4 lens wide open @ 1/25 of a second, ISO 1600, EV 0. I had read about some long exposure hot pixel issues with this camera before I got it, and had concerns, but these are new to me. Any opinions about them, fellow Pentax users? My flickr page Flickr: Adam_T4's Photostream Attached Images

12-19-2009, 01:14 PM	#8
glanglois Veteran Member Join Date: Aug 2007 Location: Madison, Wis., USA Posts: 1,506	Aircraft? Originally posted by Ash Ah, indeed - the arc of the 'artifact' mirrors that of the ferris wheel. The dots resemble the dots/streak in my images that I believe to be aircraft in, I think, the Heathrow pattern. The arc, though, is either a reflection or something from the Sontarans or the Shadow Proclamation. The photo was taken from Westminster Bridge? The angle seems off for Westminster Pier. Alas, I'm a too-occasional visitor and may have my geography mis-remembered.

12-19-2009, 03:47 PM	#10
glanglois Veteran Member Join Date: Aug 2007 Location: Madison, Wis., USA Posts: 1,506	Which part? Originally posted by Oggy The three dots look like part of the Ursa Major constellation to me. I'm almost hesitant to ask about the anatomy of the bear ....

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12-19-2009, 12:17 PM	#2
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	These don't look artifactual - they look real. These are not what hot pixels look like. During the exposure you never noticed a light-emitting object falling/rising within the scene forming the curve at left?

12-19-2009, 12:26 PM	#3
Adam_T4 Forum Member Join Date: Aug 2009 Location: NYC Photos: Gallery Posts: 51 Original Poster	I really didn't see any light source where that arc is. My attention was on the London Eye entirely at the time.

12-19-2009, 12:34 PM	#4
RBellavance Veteran Member Join Date: Nov 2006 Location: Near Montréal, Canada Photos: Gallery Posts: 1,716	Interesting... I don't think it can be a rising/falling object because the exposure time was 1/25s. Do you have a filter in front of the lens ? My only guess would be flare/reflection from it.

12-19-2009, 12:44 PM	#5
davidreilly3207 Loyal Site Supporter Join Date: Sep 2009 Location: South Jersey Photos: Gallery \| Albums Posts: 720	Definitely a reflection, if not from a filter, then off the back glass of the lens itself.

12-19-2009, 12:55 PM	#6
glanglois Veteran Member Join Date: Aug 2007 Location: Madison, Wis., USA Posts: 1,506	If that was taken from just above Westminster Pier, I may have some that I can compare to yours except for the lens.

12-19-2009, 01:02 PM	#7
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Ah, indeed - the arc of the 'artifact' mirrors that of the ferris wheel.

12-19-2009, 03:06 PM	#9
Oggy Inactive Account Join Date: Sep 2009 Location: West Sussex UK Posts: 235	The three dots look like part of the Ursa Major constellation to me.

12-19-2009, 03:52 PM	#11
Adam_T4 Forum Member Join Date: Aug 2009 Location: NYC Photos: Gallery Posts: 51 Original Poster	London is very well lit up at night, I doubt any constellations were visable. I'm going with an internal reflection, as I did have a UV filter on the lens. This would be the first time I've come across a reason to not use any filters. Thanks for the replies.

12-19-2009, 04:34 PM	#12
KungPOW Veteran Member Join Date: Nov 2007 Location: Vancouver, Canada Photos: Gallery Posts: 1,699	I concore with the others. You have filter reflection there. Always remove your UV filter for night shots. Also, stop the lens down for night shots to get sharp stars at the bright light points instead of the fuzzy blobs.

12-19-2009, 04:41 PM	#13
raz-0 Veteran Member Join Date: May 2007 Location: Central NJ Posts: 470	Internal reflections of the lights on the wheel (the side out of frame), and the more horizontal string are reflections from the lights on the boardwalk/midway/whatever. It's not the sensor.