Dead Pixel Camera

[Elisabet Schwartzkopf]

Anotherfrequently asked question from our readers is related to dead, hot and stuck pixels they encounter in images or on-camera LCD screens. Since there is so much confusion about these different types of pixel defects/malfunctions (people use them interchangeably without understanding the terms), I decided to write a quick article explaining the difference between them to avoid any confusion. Please bear in mind that there is no consensus between photographers when it comes to defining the types of pixel defects. The below information is my way of categorizing defective pixels that you might not agree with.

How to spot dead pixels: dead pixels are easy to spot on the camera LCD. Simply turn on Live View and point your camera at a bright area such as the sky. Dead pixels will always show up in the same spot even if you move the camera. Finding dead pixels on the camera sensor is tougher. Take several pictures with different colors and patterns, then analyze the image at 100% view size. If you see a pixel that shows up in the same spot and changes colors every time, or appears darker than the surrounding pixels, it is most likely a dead pixel.

How to spot stuck pixels: to see if you have stuck pixels, set your camera to Program/Auto or Aperture Priority Mode, then turn on Live View and point the camera around, while carefully looking at the camera LCD. If you notice a pixel that never moves and has the same color no matter where you point your camera to, you might have a stuck pixel on the LCD. To find out if you have a stuck pixel on your camera sensor, take multiple different pictures at a base ISO such as ISO 100 or 200, then analyze the images at 100% on your computer screen. If you have a colored pixel (actually a small cross when viewed closely) that always shows up in the same spot, you have a stuck pixel. It is normal for digital camera sensors and LCDs to have multiple stuck pixels.

Unlike stuck pixels, hot pixels only show up when the camera sensor gets hot during long exposures or when the ISO is cranked up above 400-800. Hot pixels are very normal and they will show up even on brand new cameras, although manufacturers do their best to map hot pixels out during the QA process. Hot pixels will appear and disappear over time and if your brand new camera does not have stuck pixels, you can rest assured that you will have them at some point in the future. Every single DSLR camera I have owned and/or used had hot pixels. My Nikon D3s had no visible hot pixels when it was new and now has plenty of hot pixels that are visible in longer exposure/high ISO images. Hot pixels do not occur in LCD screens.

How to spot hot pixels: while keeping the lens cap on, set your camera to Manual mode, turn off Auto ISO and set your ISO to 100 (base ISO). Set camera shutter speed to 5-10 seconds and aperture to a large value like f/16 (to decrease the amount of ambient light that could potentially enter the lens through small holes). Take a picture. Next, set your ISO to 800 and increase the shutter speed to something fast like 1/1000 while keeping the aperture the same. Take another picture. Analyze both images and see if you can spot colored pixels that look like very small crosses when zoomed in. You will probably see more hot pixels in the second photo at higher ISO than on the first one.

Unfortunately in most cases, you cannot fix dead, stuck or hot pixels yourself. While you might find some online tutorials on how to map out stuck/hot pixels with various software (only works with very old DSLR models), I would not recommend trying those. If you decide to try it out, then do it at your own risk.

I personally do not care about those, because Lightroom and Photoshop Camera RAW automatically map those out when I import RAW images. If you only shoot JPEG, then it will take a little more time to map those pixels in post-processing, since you have to touch every image. There are some programs out there that will look for pixel patterns and fix JPEG images in batches, so you can more or less automate the process as well.

Nasim Mansurov is the author and founder of Photography Life, based out of Denver, Colorado. He is recognized as one of the leading educators in the photography industry, conducting workshops, producing educational videos and frequently writing content for Photography Life. You can follow him on Instagram and Facebook. Read more about Nasim here.

Nevertheless, my D7100 is about 3 years old with a shot count of 40,000+, and mostly long exposure high ISO shots via time lapse and panorama shooting the night sky. My question to everyone is: Does the sensor wear out when there are more hot pixels due to the fatigue of heating up the sensor a lot over time?

Nasim,

Not too long ago some photographers discovered a sensor pixel-remap process that has been 100% successful for many users of a variety of Canon and Nikon bodies. It is surmised that this may be the same process the manufacturers use when remapping pixels.

The easiest way to find a dead pixel on a camera, since it is an always-black pixel, is to take a picture of something that is very light, nearly white almost, and preferably neutral in color. So, an out-of-focus picture of an evenly lit, white wall, with your white balance set to perfectly match the ambient light, will do the trick.

Then, simply open your image and scrutinize it for any black pixels. NOTE: if you see a large cluster of pixels that are very dark, but not totally black, that is probably just dust on your sensor, which is a whole different issue and fix. (See this article here about our preferred sensor cleaning method!)

On a display, whether a phone, tablet, TV, computer display, or laptop screen, the methods for finding potentially dead pixels is roughly the same concept: view a white, blank, screen, and look for black dots.

On a digital display screen, fixing a dead pixel is a bit more difficult. Again, the good news is that manufacturers know this, so they test for dead pixels very thoroughly before shipping products out, and one is very unlikely to develop randomly during the normal lifespan of the display. So, if you buy a brand-new phone or TV or whatever, and test it immediately for dead pixels, then you can either return it right away if you see one, or rest assured that there is very little chance one will show up later.

This article may not have been entirely good news, but hopefully, it can be a reminder that with a little bit of extra effort, we can try to get the best life out of all our digital devices, whether a camera or phone, or other display!

Hello,

I need help, I performed the dead pixels commands and I follows all the steps. Once the command to clean the pixels was executed the screen went black. I turned the camera as instructed and the camera viewfinder is black.

The menu screen and all the other commands are still visible. What should I do to fix this problem?

When I was starting with photography, I was asked to make some videos and photos of an event. The camera which was doing the filming was pointing at the stage, and my other camera was with me to take some photos. It was my first experience with photographing low-lit locations and with fog and lasers too. The good part is that I've learned quite a lot about how to shoot in such scenarios since, but the camera that was filming was on a tripod, and it was stationary for the whole time, with a wide angle lens to record the entire stage. Thankfully, the low magnification helped minimize the damage.

So, after the event, I've packed back everything and went back home, and to my sad surprise, there was something very strange on the footage, from the middle towards the end. There were some odd, pinkish spots that didn't look like dust spots, but in fact were the dead pixels on that part of the sensor. The laser projector was pointing towards the crowd (literally towards the crowd watching, the light beam moving around, but every now and then, it could reach people's eyes and my camera too). And these dead pixels shows on every photo that I shoot with this camera now, just like you can see on this image, where I've photographed a piece of paper and left it completely out of focus, so the only thing in the photo is the dead pixels.

It's annoying, but I still can use this particular camera, I just have to retouch the dots, but it could've been worse. I saw some people that had worse cases of dead pixels that made it not impossible but impractical to retouch every single photo due to the amount of damage to their sensors, which resulted in having to replace them. I the camera is used only for video, I don't think it's possible to remove them (depending on the amount of damage).

If you want to avoid this kind of problem, before setting your camera on a tripod to be stationary for the entire time (like me), be sure to check where the projectors are and where they are pointing.

Yeah, I remember reading Mykal Hall's experience of needing to replace his Olympus a few years ago after one of these lasers killed his sensor, too. It's good to see a reminder article such as this one sometimes, for those who haven't heard of the issue before.

The sad part of this story, is that a couple of days after my sensor was damaged by the lasers, I saw something about it (which would've helped me to prevent it from happen, a video or something like that talking about it). Lesson learned (the hard way)!

Sensors in general are more sensitive to excess light than the retina. Plus your eye only admits light going through the pupil which is 4-5 mm diameter at a light show, while a camera lens can gather most or all of the beam. (At longer distances, a light show beam can be wider than 4-5 mm so not all the light would go through the pupil.)

For this reason, the International Laser Display Association says laser show producers must make eye-safe shows but cannot be expected to be responsible for all the camera/lens/sensor combinations out there. More info is at -sensor-damage.htm

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