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07-10-2009, 08:45 PM   #76
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QuoteOriginally posted by C.W Tsorotes Quote
Ok then.

Just out of curiousity are you able to upload a demonstration?

thanks.
Sure. here is a 1:1 pixel crop ISO400 shot I just snapped. Part of what you see is a very dark object in the foreground, and the right side are better exposed objects in the background. Notice the speckly noise on the dark object? Actually, some of those pixels are fully unexposed, i.e. zero information captured.

Note that in this part of the crop, neither subject is in focus. just FYI.

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07-10-2009, 08:47 PM   #77
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QuoteOriginally posted by C.W Tsorotes Quote
In video mode I found a similar line is apparent in very dark scenes.

Also please take a look at the very dark part of the image, near the bottom where the PS3 & receiver are. It's very speckly. I'm still not convinced this is normal.


http://farm4.static.flickr.com/3522/3708946434_1ed28caf90_o.jpg
OK, you have a very faint band extending from the top of the photo to the bottom. Its in line with the extreme brightness transition from the very bright window to the very dark TV outline. This is not at all like the faint thin blue line posted by other posters earlier. What ISO setting were you using ?

It looks similar to a technical problem described in the Wikipedia link below. Its called "vertical smear". I thought it was solved with CMOS sensors, but maybe not....Its related to the sensor being unable to cope with the extreme transition from a very bright to very dark area occuring in a straight line.

Frame transfer CCD - Wikipedia, the free encyclopedia

There are many posts on the subject in dPReview's various forums.

The problem was actually technologically unsolvable in CCDs, though most users would hardly notice it - camera manufacturers just used on-board software processing to heavily correct the problem, not solve it.

I haven 't noticed anything on my K-7 unit yet...I'm sure Pentax can fix this one with firmware if its a common problem.
07-10-2009, 09:16 PM   #78
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Well, I'm not sure what to do. I have not been able to reproduce the line again, but I also haven't shot jpeg again. I suppose this might support a thesis that, in my case, the faint line is a jpeg issue. However, as BH require a camera to have less than 200 exposures shot, I can't really test this out further.

What to do. Harumph. I'm half tempted to ignore the issue and, if it comes up again, send the camera to Pentax.

Hmm.
07-11-2009, 01:11 AM   #79
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QuoteOriginally posted by arpaagent Quote
Sure. here is a 1:1 pixel crop ISO400 shot I just snapped. Part of what you see is a very dark object in the foreground, and the right side are better exposed objects in the background. Notice the speckly noise on the dark object? Actually, some of those pixels are fully unexposed, i.e. zero information captured.

Note that in this part of the crop, neither subject is in focus. just FYI.
Ok! cheers because thats precisely what i'm seeing.

I've never encountered that on a camera before, I found one solution was in photoshop if shooting raw is to tweak the black level.

Your explanation makes a lot of sense now.

Strangely its more apparent using MS Picture viewer than in photoshop

http://farm3.static.flickr.com/2523/3709519364_09c81cdbf6_o.jpg

Here's a slightly underexposed outdoor shot I took today, its apparent on the bottom left and wherever else its dark or there is black.

07-11-2009, 01:31 AM   #80
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QuoteOriginally posted by Torphoto Quote
But mine shows up with NO live view!!

then again I am in tropical heat so ....


Also notice the same line at 100 iso
i think i might have gone blind as i can't see any line in this photo you attached at https://www.pentaxforums.com/forums/attachments/pentax-dslr-discussion/38427d...lipboard01.jpg ???
07-11-2009, 01:46 AM   #81
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QuoteOriginally posted by eva2000 Quote
i think i might have gone blind as i can't see any line in this photo you attached at https://www.pentaxforums.com/forums/attachments/pentax-dslr-discussion/38427d...lipboard01.jpg ???
If you look carefully, its inside the Red box.
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07-11-2009, 01:57 AM   #82
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QuoteOriginally posted by K-9 Quote
Camera stores like Ritz in the US and Jessops in the UK seem to stop carrying them, and this may well secure that anyone who still is, doesn't anymore.
Jessops here in the UK are in dire financial trouble (only just scraping up enough to pay their rent the last quater). Pentax have refused to supply equipment to them on credit which is why they no longer stock the brand.
07-11-2009, 02:09 AM   #83
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QuoteOriginally posted by kittykat46 Quote
If you look carefully, its inside the Red box.
i had to view that boxed area of the photo at 800% magnification to even see a glimpse of the line. Honestly, I wouldn't have picked it up if you didn't tell me where to look.

07-11-2009, 02:13 AM   #84
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kittykat46 i can see the line barly but i do see it. Is that image a 100% crop of the original? and is it dead center of the picture if cropped.
07-11-2009, 02:23 AM   #85
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QuoteOriginally posted by Dr_who Quote
kittykat46 i can see the line barly but i do see it. Is that image a 100% crop of the original? and is it dead center of the picture if cropped.
That was from Torphoto's post, actually. I think its a corner crop from the original.

I haven't seen the problem on my own K-7, and I live right on the Equator - 32 c noon-time temperature outdoors.
07-11-2009, 03:16 AM   #86
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It was mid 20's here today and I probably wouldn't have even noticed my line today until I zoomed right in to look at the detail on my photos and saw the band I took 3 images from the street performers and put them on layers above each other and they line up in the same spot each time. I did however record video of a performer before hand and that might have contributed to it. I pixel peeped at images prior to the video and can't find the lin, sometimes I find almost not a line but a concentration of noise line but its so faint I can only see it at 400%.

Just took a image while at home and the camera hasn't been used for some time. Took a picture of interior door and don't see it...Is ther eany adjustment sin photoshop that helps bring them out.

Here are my images with the line. The photos were all at 200 ISO as it was pretty sunny afternoon. at the bottom of the image is the 100% crop of the area in red at top of image. http://stevenkovickart.com/pentaxforums/elvisline.jpg


It may be also worth to note that most of these posts have been about under expossed photos, where mine are very sunny well lit photos.

Last edited by Dr_who; 07-11-2009 at 03:21 AM. Reason: added info
07-11-2009, 03:31 AM   #87
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QuoteOriginally posted by Dr_who Quote
It was mid 20's here today and I probably wouldn't have even noticed my line today until I zoomed right in to look at the detail on my photos and saw the band I took 3 images from the street performers and put them on layers above each other and they line up in the same spot each time. I did however record video of a performer before hand and that might have contributed to it. I pixel peeped at images prior to the video and can't find the lin, sometimes I find almost not a line but a concentration of noise line but its so faint I can only see it at 400%.

Just took a image while at home and the camera hasn't been used for some time. Took a picture of interior door and don't see it...Is ther eany adjustment sin photoshop that helps bring them out.

Here are my images with the line. The photos were all at 200 ISO as it was pretty sunny afternoon. at the bottom of the image is the 100% crop of the area in red at top of image. http://stevenkovickart.com/pentaxforums/elvisline.jpg


It may be also worth to note that most of these posts have been about under expossed photos, where mine are very sunny well lit photos.
again i'm not seeing the line even at 800% maginifcation ?
07-11-2009, 03:36 AM   #88
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you zooming in on the 100% crop or the red area. once you resize the image down its all but gone. Also its possible due to software use or monitor calibration your just not able to see the subtle changes for the line.


I looked at 800% on my computer and can't see it either. your way too close pixel peeping there. 100-200% is the best. I took some more picts indoors and oddly enough for me I find it easier at low ISO. High ISO it gets mixed in with all the noise.

Last edited by Dr_who; 07-11-2009 at 03:52 AM. Reason: added info.
07-11-2009, 04:17 AM   #89
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QuoteOriginally posted by Dr_who Quote
you zooming in on the 100% crop or the red area. once you resize the image down its all but gone. Also its possible due to software use or monitor calibration your just not able to see the subtle changes for the line.


I looked at 800% on my computer and can't see it either. your way too close pixel peeping there. 100-200% is the best. I took some more picts indoors and oddly enough for me I find it easier at low ISO. High ISO it gets mixed in with all the noise.
100% through to 800% can't see it - looked at every part of the photos
07-11-2009, 05:34 AM   #90
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QuoteOriginally posted by eva2000 Quote
100% through to 800% can't see it - looked at every part of the photos
What screen are you using? I'm having a hard time spotting it on my laptop's lcd but it sticks out clearly on my 21" crt.
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