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[OM] Re: scratch line on digital image

Subject: [OM] Re: scratch line on digital image
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Wed, 13 Dec 2006 08:27:35 -0500
In thinking about this some more it occured to me that that the vertical 
or column stripe from a certain point to the edge of the frame might 
very well be an electrical glitch in the readout electronics of the 
chip.  I looked up the technical spec for the sensor
<http://www.kodak.com/ezpres/business/ccd/global/plugins/acrobat/en/datasheet/fullframe/KAF-8300LongSpec.pdf>
but I'm not smart enough to interpret much of what any of this means.  I 
can't even be sure whether the device reads a horizontal row at a time 
or vertical column at a time or how the failure of a single component 
might affect follow on pixels from the same row or column.  But I think 
it could by affecting either the clocking of the signals or the 
buffering of values being passed out or other things I don't know about. 
  Or, as the former defense secretary would say, the "unknown unknowns" 
as opposed to the "known unknowns".

In any case, I think you should record the exact pixel locations of the 
glitches and examine more shots for evidence both past and future.

Chuck Norcutt

John Hudson wrote:

> Does that make the camera a dud or a prized collectible !?
> 
> jh
> 
> ----- Original Message ----- 
> From: "Chuck Norcutt" <chucknorcutt@xxxxxxxxxxxxxxxx>
> To: <olympus@xxxxxxxxxx>
> Sent: Wednesday, 13 December, 2006 08:34 AM
> Subject: [OM] Re: scratch line on digital image
> 
> 
> 
>>Perhaps yours is the 1 in 10^13 photos that exhibits the 1 in 10^-13 bit
>>error rate (or whatever it is) of modern computer electronics.  Could be
>>an error in encoding, storage or retrieval.  But keep an eye out for a
>>repeat as it could be more sinister.
>>
>>Chuck Norcutt
>>
>>John Hudson wrote:
>>
>>
>>>The attached uncropped photo was taken with available window with a 50mm
> 
> /
> 
>>>f2 macro lens on an E-500. The shutter speed was 1/80 sec at f4 at 800
> 
> ISO.
> 
>>>www.JohnHudsonPhoto.com/Temp/JB120335.jpg
>>>
>>>Starting at the right hand side of the pupil in the child's left eye is
> 
> an
> 
>>>unmistable one or two pixel wide "scratch" line that extends vertically
> 
> down
> 
>>>to the bottom of the image.
>>>
>>>The line comprises pixels that are predominantly more red than the
>>>surrounding pixels.
>>>
>>>The line becomes visible when the image is enlarged to 200% in PhotoShop
> 
> and
> 
>>>progressively more so as the percentage increases.
>>>
>>>I cannot find the this phenomenon repeated on any other images taken at
> 
> the
> 
>>>same or any other time.
>>>
>>>Can anyone offer a suggestion for the cause of this "scratch" line?
>>>
>>>John Hudson
>>>
>>>
>>>
>>>
>>>
>>>
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> 
> 2006-12-12
> 
>>
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