Canon 5D MK3 “Hot Red Pixels” on long exposure

[UmiKaibutsu]

I did some 30 second exposure, tantamount to bulb. I noticed a handful of really red pixels across all the images. The longer the exposure, the redder they are. So if I ever do important long exposure, such as at night/sky, there will apparently be a whole new solar system of red stars in all my images. Anybody else know about this? I was using an LED keychain with blue tint light in a blacked out room to paint light onto a variety of items to bring them into the picture. I do not think it could be anything but over sensitive pixels. The camera was moved about, the red pixels are precisely in the same position each time.

[cls]

Hi, I believe many cameras have this "additional feature". I'm not sure if there's a DIY way of turning these pixels off for your 5D3. A few years ago I discovered the same problem on the Rebel T1i I had back then. I googled it a lot and there were tips saying something like letting the camera be in sensor cleaning mode for some time with the body cap on. I tried various methods without result.

What really made a difference for me was when I moved into Lightroom. LR kills all those hot spots automatically (which basically means that I've never seen the hot pixels that my current 7D probably has).

[ahab1372]

Doesn't the long time exposure noise reduction take care of those?


Arnt

[Dr Croubie]

Same problem on my 7D when it was 3 months old. Tried the "sensor cleaning face-down for 2+ minutes", no change. Ended up sending it back for warranty-service, 3 times before they actually got rid of the last one.

or yeah, just kill them in PP.

[Kayaker72]

Hot/dead pixels are a fact of life, IMO. I was advised on this forum that everytime you put the camaer in "manual" self cleaning mode, that the camera would map the hot pixels and turn those pixels off. I tried it on my 7D a couple of times and the first few times it seemed to work. But there were some that never went away. My quick quess is that method gets the hot pixels that form in 1-2 seconds but not those that show up later.

But for long exposures, post processing is going to be necessary.

[conropl]

I have a fair number of bad pixels with long exposures. I tried all the reported fixes, but never saw a difference. The long exposure N.R. never really helped much either. I used to use DPP and P.S. Elements and it was irritating having to remove all the red, blue and purple pixels. Then I got Lightroom and I never saw them again... removes them automatically in the RAW conversion process (I will see them for a second while the shot opens, but they disapear as it fully rendors the jpeg view). At first I had mixed feelings about the software doing this action without me controling it or approving it or the results. However, I soon got over it when I let go of my control freak tendancies and realized LR did a good job and saved me a lot of work.

[neuroanatomist]

Had one red pixel on my 1D X, manual clean remapped it. DxO also removes them automatically.

[conropl]

The manual clean remap never seemed to help me. But it sounds like it does help others (neuro amongst others). If you want an explanation of how, here is link to explain how. At the end there is an update that gives a rudimentary reasoning for how it works.

http://shmuliphoto.wordpress.com/200...t-pixel-canon/

Neuro - The above is how I did it. Is there a better procedure... one that may be more successful?

[UmiKaibutsu]

I did notice it was cleaned up a bit opening from Bridge into PS CS6 but I didnt try LR. The spots were dimmed down a lot and whitened, but they don't go away. There are a lot of them. I'll try LR later, but I don't normally use it. I tried to start using it for tether, but I got so used to EOS Utility tether because I thought it had more features. I guess I can practice with LR anyway.

With the red pixels not being totally cleaned in the raw transition, I wonder what happens if I actually do bulb, I am guessing it will be a lot worse. I have a remote ordered, I think it does bulb but not sure.

[conropl]

With the red pixels not being totally cleaned in the raw transition, I wonder what happens if I actually do bulb, I am guessing it will be a lot worse. I have a remote ordered, I think it does bulb but not sure.

If you have your camera set to bulb and you go over 30 sec, it will probably get worse. And yes, the remote will work with the camera set to bulb. An intervalometer type allows you to set the interval, but with a standard remote you have to hold the button down (or push the button and slide a button actuation holder over the button to hold it down). As long as the button is held down on the remote the shutter will remain open in bulb mode.