Dead Pixel Fixer Video

[Otilia Mojarro]

Ihave finished the colour grade on a short film and afterwards, have spotted some shots used with a certain camera throughout the production that have dead pixels. I have scanned through the dailies and can confirm they are present from the day they were shot - so this is nothing to do with any post production or data transfer.

My question is whether or not it would be worth trying to fix - or just leave it and hope the majority of viewers wont notice. As I want to avoid any possible degradation and compression of the overall image during the post pipeline.

I used to work for Channel 4/Film Four QC and failed quite few a high profile things for stuck pixels. Generally you miss them if its a few shots. But if they are persistent and on light backgrounds it would be a QC fail. (well it would have been in the good old days when I did it)

Its a pretty easy fix - there a quite a few dead pixel buster plugins that fix the problem quite simply. I always used to reject programmes for dead pixels because its such and easy fix and only represents lazyness on the online editors part. Lots of post houses came to hate me over the years...

I would also fix it because even if the audience don't notice it, I would notice it and then I'd worry that other people would notice it... Its a very simple fix - depending on your software.... google is your friend here, plenty of online tutorials

So, tonight I was shooting some tests on 1250 and 2500 ISO and saw some dead pixels. They would appear when the image first displayed on the LCD screen and then they would disappear. Same thing when I viewed most of the images on the computer. Somehow, the dead pixels would get resolved by the software. However, I was able to grab some images with this issue.

It looks like I have four to six dead pixels, which appear either blue or red against a black background. The other problem I noticed is that sometimes, the dead pixels that are blue have faint blue lines that extend downward from the dead pixels to the bottom of the frame.

I purchased my M8 last week and am already planning to return it to the dealer who will then send it along to Leica, NJ, because its rangefinder needs alignment. Now, I figure this issue with the pixels/lines will need repair as well. What is the fix for this issue and how should I describe it when I return the camera?

Every camera have some dead pixels. The real issue is if it is mapped correctly, in that case you will not be able to see it in the finished files. If you can in fact see the bad pixels once imported to your computer, then the camera need some TLC for that.

They will know exactly what you're talking about, it's not an isolated case. It's relatively straightforward for Leica to fix. AFAIK there are 2 possible fixes depending on the severity of the problem, one is mapping out the dead pixels out or a complete sensor replacement. In my case they replaced the sensor.

Bo, can you clarify what you mean by mapped out--specifically, when this takes place? Unfortunately, my MacBook Pro is in the shop this week for some repairs of its own, so the software I have available to be right now is very limited.

I will use the images I link to below as an example. Note that they are scaled down to fit my screen. When I open the raw DNG file in Apple's Preview (first image) I see four dead pixels--three red and one blue--and two vertical lines. However, after I choose "Save As" and save the image as a JPEG, the dead pixels go away. However, the two vertical lines just to the left of the paper remain (second image).

Given the fact that I already need a rangefinder alignment, should I have the camera sent off to Leica under the dealer's warranty for repair or should I see if they can swap if for a different, used M8? My instinct is that swapping for another camera could open a whole other can or worms, er problems, and I'm inclined to get the one I just bought fixed because it seems to have been hardly used at all by its previous owner and, therefore, should have a good life left in it--at least from a mechanical point of view. Thoughts on this question?

I had similar issues with my M8 when it was new. But a quick trip to the Leica General Hospital cured it. I would suggest that you had this camera fixed by Leica rather than exchanging it for another. Besides fixing the alignment and dead pixel issues, Leica will also check the entire camera and make any other adjustments that they deem necessary. If you did swap it for another camera, you might have the same problems anyway. This seems to be a pretty common problem, and most cameras require a trip to Leica to be re-educated at some point.

Just clarification, probably unnecessary: Leica has always given a one-year warranty after a billable repair. The don't extend the warranty each time you send in a camera that's already under warranty.

I have four hot pixels on my M8, only one of which I noticed until I did a test. I always shoot RAW. So I found a free utility called "Pixel Fixer" that supports the M8. It quickly map the hot pixels out of DNG files, and rewrite them. It's here:

Pixel Fixer needs a reference picture. With the M8, I took one with the lens cap on at ISO 1250 and 1/30. With too slow a shutter speed, the M8's dark frame subtraction kicks in and the hot pixels may disappear from the file. Too fast a shutter or too low an ISO, and the pixels may not glow brighter than the threshold needed for Pixel Fixer to map them.

One I fed the above file to Pixel Fixer, it saved a configuration for the M8 that has each hot pixel marked. After I copy the DNGs off my SD card, I just point Pixel Fixer at the folder, press Go, and in a minute or two, I'm ready to start Capture One.

If you shoot JPG, have a lot of hot pixels, or if using a utility like Pixel Fixer doesn't remedy the vertical lines that sometimes extend down from hot pixels, then a trip to Leica is warranted. In my case, Pixel Fixer seems to do the job.

I have no connection with the author of the program or his company, I just use the product and found it to do the job nicely, with no fuss. I should note that my Olympus DSLR has a utility in its menu to detect and map out hot pixels in the camera, so no external software is needed.

I had this very problem with my 2nd hand M8 in november. My M8 was immediately sent to Solms for a 3 week repair.. they fixed the ccd and threw in a 100% cla including rangefinder and to top it all a 1 year warranty. This was all done under (I think) camera stores warranty, which means the camera store paid for it..

Anyways, I'm really happy with the outcome even if it meant I had to live whole 3 weeks without my "new" camera. Trust me, it was a painful wait! I got it back just week before xmas, which naturally was really nice

Does anyone have any sense whether or how often the factory refurbished M8s show these faults? These threads make me nervous, but I haven't been able to find lines in my M8 files - my M8 was purchased as a refurb.

John: The more serious of the two "vertical line" problems requires a sensor replacement. If you're getting a refurb, then it would be covered under warrantee. In some respects a refurb is better than a new camera, because it's been "burned in" and used a little, and fixed (we hope) if it was broken in any way. So it might be less likely to have a problem.

It *appears* that often, the blue vertical line one pixel wide is caused by the demosaicing algorithm in the camera or image software getting confused by a hot pixel on a dark background. This effect cascades down the sensor, because each pixel is afftected by its neighbor with respect to color reconstruction on a Bayer sensor. If you remove the hot pixel--either by Leica mapping it out, or by using external software like Pixel Fixer--the line disappears along with the hot pixel.

That's what happened with my M8. I occasionally noticed one hot blue pixel. Recently, when I noticed a faint vertical blue line under that hot pixel on a high ISO shot, I decided it was time to do something.

So I downloaded Pixel Fixer. It detected that hot blue pixel and three others (red and green) that I hadn't noticed. It was *not* mapping out the blue line below the blue hot pixel. I ran it on the entire folder from that day of shooting. The output files from Capture One showed the hot pixels gone, and had no more blue lines. Problem solved.

All cameras have or develop a few hot pixels. Some manufacturers, like Olympus, include a "detect and map out" function in the camera menu. Leica, like some others, requires you to send the camera back to the mother ship to map out the pixels. Software like Pixel Fixer is an alternative quick way to deal with the problem, if you don't mind running a program on each folder of RAW files before you process them.

The early M8s had another, more serious problem with a line down the sensor that wasn't just a matter of mapping out a hot pixel. That one requires a trip to Leica. We heard a fair amount about it in the first months of the M8's life. Not so much since then.

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