[Leica] IMG: what's happening with the vertical blue line? sensor failure?

[pklein at threshinc.com (Peter Klein)]

Adam: The M8 and M9 will sometimes display such lines if there is a hot 
pixel. You will get a line the same color as the pixel, starting with 
the hot pixel, and running all the way down the frame.  There can also 
be a bona fide sensor problem that causes these lines. The latter will 
require repair by Leica.

You may be able to determine if it's a hot pixel by taking some pictures 
at various ISOs with the lenscap on. Use zero sharpening, and look for 
brightly colored squares. If the blue line is always present and 
occupies the complete column from top to bottom, then it's more likely 
that the entire column is bad . The higher the ISO and more you bring up 
the shadows, the more likely these things are to show up, and the more 
likely a single hot pixel is to turn into a line. On JPGs, the hot pixel 
may appear as a dot, or be processed into a little cross if you look at 
high magnification.

If it's just a hot pixel, you can send the camera back to Leica for a 
tune-up, and they'll map out the pixel. Or, if you're a PC user, you can 
use the free program Pixel Fixer to map out the hot pixel. The line will 
disappear as well, it's not real, it's just a processing artifact. You 
feed pixel fixer an image taken with the lens cap on and high ISO. It 
creates a map file which it then uses to interpolate the bad pixel based 
on its neighbors' values. You can run it on individual files, select 
files or entire folders (RAW only, not JPG).

See here:
http://www.pixelfixer.org/

Other cameras like my Olympuses (Olympi?) don't have the problem because 
they have an in-firmware routine that detects and maps out such hot or 
dead pixels. Mit Leica, you haff to send it back to ze Muttership.  Or 
use Pixel Fixer.  Only problem is it's a PC/Windows program, no Mac version.

I've happily used Pixel Fixer for years.  Oh, if you use Lightroom, it 
can do the same thing Pixel Fixer does. You'll have to get more info 
from a Lightroom user, I don't use it.

--Peter


 > In this image:
 >
 > 
<http://adam-bridge.smugmug.com/gallery/32225777_wkgvQx#!i=2825025517&k=n3D8gVM&lb=1&s=O>
 >
 > There's a clearly visible vertical blue line toward the left side of the
 > image and another vertical one where the dark chimney meets the 
bright side
 > of the building.
 >
 > What's going on here? Do I have a sensor going bad on me? I haven't seen
 > these in other images
 >
 > Shot with an M8 at iso 1250.
 >
 > There's nothing fabulous in this image, it just illustrates the 
problem that
 > was revealed tonight when I did of dark photography.
 >
 > Shot with the Voigtlander 35mm f1.2, wide open.
 >
 > Thanks for commenting
 >
 > Adam