Adobe Flat Field  

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Ulana
(@uswitucha)
Joined: 3 years ago
Posts: 376
May 17, 2019 6:41 am  

Well I never thought that I would ever post in this section......a friend of mine sent this post to me.  

Adobe Flat Field

Over to you @rshinde 


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John Motzi
(@jmotzi)
Joined: 3 years ago
Posts: 269
May 17, 2019 2:23 pm  

Hi Ulana,

That was an interesting article.  Eric is a cool guy - he is the guru of a lot of technical stuff in Lightroom.  I used to order custom paper profiles from him some years ago when I was using some odd papers.

There is a similar feature/process in Capture One Pro called LCC = Lens Cast Correction.  Some of the medium format technical camera folks use that because they are using large format lenses and tilts/shifts that result in vignetting and non-uniform color casts.  What they often do is shoot through a translucent white plastic which is either held over the lens or placed in the filter holder.  That way they can do a separate lens cast correction profile for each frame if "necessary" and they don't need to go hunting for white walls.

JM


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Raaj
 Raaj
(@rshinde)
Joined: 3 years ago
Posts: 685
May 17, 2019 5:04 pm  

Hi Ulana,

Thanks for sharing this.  I am impressed that LR now includes this capability, though I don't use LR at all.  Flat Fielding, like Dark Frame Subtraction, is a staple in the astrophotography world to eliminate the vignetting/distortion from long optical trains.  Astro image processing tools like PixInsight have powerful support for these techniques.  As John mentioned, also used in medium and large format photography.  

I've used a white document on my computer screen to generate Flat Fields in the past, as uniform lighting is essential.  People routinely use white tee shirts draped over the lens/telescope and pointed at the sun to generate Flats, as they are called.  Long exposure noise reduction is a form of dark frame subtraction in-camera.  I believe Capture NX has dark frame subtraction features built in too.

Cheers!

   


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