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I've always been a stills shooter underwater, but when I won a video light in a photo competition recently I thought what the heck, I'd make an attempt at shooting some video for a change.

 

First thing I notice when I get the footage on my computer screen is that I seem to have some stuck pixels, particularly a decent-sized red spot near the middle of the frame. I guess these have always been mapped out with my images in Lightroom, so I never really knew they were there.

 

Help! What can I do? It's awful, and completely ruins the video.

 

I am shooting with a Canon 5D Mark II. It's a camera I've had for years (well out of warranty).

 

Thank you Wetpixelites!

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Alison,

 

Interesting...

 

Almost sounds like something I'd get if there was a "blown out" or overexposed spot in the video. Don't ask how I know this.

 

Could you post a frame capture to give a better idea of what you're describing? Two or three might be better.

 

Tom

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Does this picture help to illustrate?

dfc455aa70f83cb6962fe769e4b960bc.jpg

The red spot (pointed to by arrow) is particularly bad.

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Alison,

 

Not an expert - just trying to think it through.

 

It looks like you have "boxed" a number of the spots you consider problematic, and "arrowed" the most objectionable one.

 

I realize your camera has a built-in self-cleaning mechanism for the sensor. It looks a lot like there may be some specks stuck to the sensor that the built-in cleaner can't get rid of. A big clue would be to note whether the spots stay in the same places for two or more different scenes. If so, I'd bet on the sensor being contaminated.

 

If you have access to a shop you trust, you could take it in for inspection and perhaps cleaning. I've done the cleaning myself a few times, but it is a very delicate process with the possibility of damaging the sensor. You can search WetPixel and/or the web to find out more.

 

If the spots move around from one scene to another, I'm stumped, unless they are somehow related to reflective surfaces having a kind of "red-eye" effect.

 

Tom

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Yep, that looks a lot like a classic "dead pixel". I usually see this on LCD monitors. The photo you showed - was this a screen capture, or an image from photoshop?

 

If it's really on the image, then it would certainly suggest a dead pixel on the image sensor. Does your camera have a "dead pixel" mapping function? I've never had to use the function on my cameras, but that would be the most appropriate way to address the issue if your camera has that capability.

 

Otherwise it would require post-processing. For photos - that's pretty easy. But I'm out of my depth on post-processing video. There may be some intelligent post-processing algorithm in the better video editing suites that would track that spot and remove it, especially given a dead pixel will not move at all during the entire clip.

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It was a screen shot that I took while the video was rolling on my laptop.

 

The "stuck pixels" don't move or change colour throughout any video that I shoot. I believe Lightroom must automatically map these out and remove them because I never see them when processing my stills - and they are so big they would be obvious!

 

I don't think it's anything on the sensor. I'm familiar with what dust spots look like when you photograph a sky and this doesn't look anything like that. I have sensor cleaning each time I turn camera on and off.

 

It's quite the conundrum. I'm reluctant to waste my time on any further video shooting if there's no solution. :-(

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Alison,

 

Obviously something that doesn't change is creating spots only in your video. I'd be astonished if Lightroom is smart enough to automatically correct those spots without your input for the still photos - not impossible, but unlikely.

 

Could the laptop screen have some dead pixels?

 

Do you use the same lens for video as for stills?

 

Just fishing ;-) ...

 

Tom

Edited by wydeangle

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Same lens used for video as for stills. No issues with laptop screen. Those spots only appear in videos.

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Alison,

 

Fascinating. All possible causes have now been eliminated :o

 

(just kidding)

 

What software are you using to edit/play the video?

 

Tom

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Thanks Gudge. Have you used any of these techniques?

 

I just have the free iMovie on my laptop for video editing so far as video hasn't been a focus for me.

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Gudge,

 

Thank you! You have taught me something useful.

 

An internet search here: http://Stuck or Hot Pixels from Video Footage

 

gives the impression there's a whole stuck pixel industry devoted to software fixes for the problem.

 

Who'da thunk it :crazy:

 

Thanks again,

 

Tom

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Thanks Gudge. Have you used any of these techniques?

 

No, I only shoot stills but I do like to find solutions to intriguing problems.

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For those wondering whether Lightroom automatically maps out dead pixels, I just came across this in Adobe Photoshop Lightroom CC/6

The Missing FAQ by Victoria Bampton:

 

HOT PIXELS
If you’re wondering where
your hot pixels on your
camera’s sensor have gone,
Lightroom automatically
maps out hot pixels, as does
ACR, but it only works on
standard raw or mosaic DNG

files, not sRAW.

Edited by Gudge
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