Dust shadow fix

[John Marchant]

What are your preferred methods for fixing dust shadows on Red footage? The distance from OLPF to sensor renders dust spots quite soft, but that can mean they're over a number of pixels if they do appear.

Any clever tips? I've fixed short shots in after effects with effort before, but the nature of the aberration would seem to lend itself to an automated fix- nothing in the footage is obscured, just marginally darkened...

 

[Robert Hart]

This and vigettes were an often problem in the days of Noah and groundglass adaptors. One trick ( and I am reasonably sure the originator as far as post on groundglass work was concerned visits here on this forum ) was to shoot a reference mask without disturbing the artifacts against a white background, then invert the mask in another layer over the image at various transparencies rto make it go away. There were some chroma tricks which were similar in general principle. The trick I think was also used when the groundglass motor was not switched on due to operator error or with static adaptor groundglass artifacts.

 

[John Marchant]

Cheers for that pretty sure a clear blue sky could be adapted to that methodology with some effort

 

[Michael Romano]

Very clever. A travel matte from the plate should do the trick quite nicely. If you can't get the plate, a simple, static feathered mask in your CC of choice should fix it up.

 

[Björn Benckert]

Do this, shoot a gray card compound a few frames so you got no noise. Basically mix 10 frames together. Then you take that frame and blur it heavily. Take the blurred frame and the compounded frame and pull difference. Then you have a perfect key for your dust spot. (It works for every lens as your dust is on the actuall sensor it does not move or such.)
Then use this perfect matte to pull gamma, and lift until the spot is gone. usually the same setting holds up quite well.

Then next time, bring sensor swabs to set and keep an eye out for those things.... I just made the same mistake not to long ago

 

[John Marchant]

Cheers Björn, these are all variations on my current method, but useful to hear

The dust that got me arrived mid-shoot... it was just personal stuff shooting planes at a military airshow. A perfect storm for dust spots. Long lens plus mega dusty environment, compounded by a tight f-stop, and topped off with flat blue skies filling the frame.

Life in stills land is so much easier sometimes.

Here's the worst of the ugliness after a second spot arrived to join the first. Looks almost invisible till you push the grade around... I loaded up the R3D on the camera and really couldn't spot it on the LCD.

https://vimeo.com/71051679

Pleasantly surprised with the lens I used - this was mostly an excuse to play but I was nominally checking out this lens for a specific upcoming job.

 

[Bob Gundu]

You can also use the close tool in After Effects. Set it up on the first frame and it will repeat automatically for each frame.

 

[John Marchant]

Thanks Bob, I hadn't looked at that previously.