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06-17-2019, 12:30 PM   #1
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New K70 sensor problem

I got a new K70 two weeks ago and I was out shooting some street photography this evening (with a really dreadful old kit lens that needs replacing) and I'm trying to mess around with manual mode. In one of the backlit shots I was trying to take there is a strange purple "light" and lines across the screen. I know the lens is dreadful but it looks like a sensor problem to me. Has anyone else experienced this? Any advice?
https://app.box.com/s/iop9rcigbk829sfrusulzc7f3h1zevgf

This photo also has a strange pattern in the same spot when zoomed in
https://app.box.com/s/rmpxhfdydnzisgyx5q8ill8ci6tp5cui

---------- Post added 06-17-2019 at 10:36 PM ----------

I tried to post photos, but they didn't post.

https://www.flickr.com/photos/16125760@N02/48081496501/in/dateposted-friend/


Last edited by ikonographics; 06-17-2019 at 01:01 PM.
06-17-2019, 12:39 PM - 1 Like   #2
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QuoteOriginally posted by ikonographics Quote
I tried to post photos, but they didn't post.
right click and view image works.

Just looks like a bad case of lens flare to me.
06-17-2019, 12:40 PM   #3
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Unless I'm missing something it looks like lens flare to me. Colors are probably from the coatings on the lens elements.
06-17-2019, 01:04 PM   #4
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The strange pattern and blue lines across the screen don't look like lens flare to me.

---------- Post added 06-17-2019 at 11:05 PM ----------

I can't see any of the images I'm trying to post so I don't know if they have actually posted

06-17-2019, 01:06 PM   #5
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QuoteOriginally posted by pschlute Quote
right click and view image works.

Just looks like a bad case of lens flare to me.
Where are the responders finding his photos?
06-17-2019, 01:18 PM   #6
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QuoteOriginally posted by ikonographics Quote
The strange pattern and blue lines across the screen don't look like lens flare to me.

---------- Post added 06-17-2019 at 11:05 PM ----------

I can't see any of the images I'm trying to post so I don't know if they have actually posted
The purple is from the brilliant light of the sun (which is typically 100,000 times brighter than the scene) reflecting off the floor of the mirror box. There's no "black" coating known to man that is perfect. A lens with a good lens hood designed for APS-C can help.

The blue lines are sensor artifacts caused by the design of the sensor. Unfortunately, Pentax has followed other camera makers down to road of using image sensors with built-in PDAF and that creates these artifacts.

P.S. I used pschulte's instructions to see the images ("right click and view image works").

Last edited by photoptimist; 06-17-2019 at 01:28 PM.
06-17-2019, 01:24 PM   #7
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QuoteOriginally posted by jgnfld Quote
Where are the responders finding his photos?
I'm not seeing the photos either...
06-17-2019, 01:27 PM   #8
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QuoteOriginally posted by jgnfld Quote
Where are the responders finding his photos?
I've been wondering that too, but at least someone is seeing them even if I can't! (I'm a woman, btw )

---------- Post added 06-17-2019 at 11:31 PM ----------

QuoteOriginally posted by photoptimist Quote
The purple is from the brilliant light of the sun (which is typically 100,000 times brighter than the scene) reflecting off the floor of the mirror box. There's no "black" coating known to man that is perfect. A lens with a good lens hood designed for APS-C can help.

The blue lines are sensor artifacts caused by the design of the sensor. Unfortunately, Pentax has followed other camera makers down to road of using image sensors with built-in PDAF and that creates these artifacts.
Thank you so much! You've spared me 4 hours on buses and trains to return it tomorrow! I'm sure the dreadful lens didn't help the situation.

06-17-2019, 01:55 PM   #9
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QuoteOriginally posted by pschlute Quote
right click and view image works.

Just looks like a bad case of lens flare to me.
QuoteOriginally posted by Not a Number Quote
Unless I'm missing something it looks like lens flare to me. Colors are probably from the coatings on the lens elements.
QuoteOriginally posted by ikonographics Quote
The strange pattern and blue lines across the screen don't look like lens flare to me.[COLOR="Silver"]
Apparently, you are looking at different images than what was linked to or your device for viewing is not cooperating. What I see is bad flare and artifact. I see no blue blue lines across the screen, though I do see three small blue dots in both images.

The page url for #1 is:
Code:
https://app.box.com/s/iop9rcigbk829sfrusulzc7f3h1zevgf
The page url for #2 is:
Code:
https://app.box.com/s/rmpxhfdydnzisgyx5q8ill8ci6tp5cui
Both are a Web page at box.com that displays preview JPGs, the first of which is a guy outside an Indian Restaurant looking at used furniture and other stuff on the sidewalk. The second is of the same scene, but with a different person walking towards the camera. Near his left ankle is a small pattern of three bright blue dots with a bluish haze around them. Extra-dimensional being?

Edit: I downloaded the actual files and on further examination, both photos have a similar pattern of blue dots at the same location in the scene, but at different places in the frame. They appear to be light refracted from a colored glass object in the crate behind the "dots".

Both have bad flare and fringing. I see no banding, purple, blue, or otherwise.


Steve

Last edited by stevebrot; 06-17-2019 at 02:10 PM.
06-17-2019, 02:26 PM   #10
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I don't see the images in the top post, either. I tested with Firefox while logged in to my PF account, and Chrome while not logged in.
06-17-2019, 02:27 PM   #11
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I see a couple of 1 pixel high horizontal lines in the purple flare of the first shot, but it just looks like a momentarily maxed out sensor, I'd take a shot of something neutral to check, but it's probably just a momentary glitch caused by part of the flare as the sensor was being scanned.

Edit;
Yeah, I couldn't see the images in chrome - I used stevebrot's links.
06-17-2019, 03:25 PM   #12
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QuoteOriginally posted by sqrrl Quote
I see a couple of 1 pixel high horizontal lines in the purple flare of the first shot,
OK...I see them now. There are ten total at regular vertical intervals, but not reaching fully across the frame. There are none in the second shot.

FWIW, both images have taken a pass through Lightroom for DNG conversion to JPEG with apparent default settings.


Steve
06-22-2019, 05:37 AM - 1 Like   #13
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I've seen something like this when I tried to capture lightning strikes and one was really close and completely overexposed the shot.

Taken on a Nikon 1 V1 with an ND filter in front of the lens, exposure tuned down a few stops in post.

I got to the conclusion it must be some circuitry on the sensor that is only visible when completely overexposing parts of the image.
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