Center Filter Procedure?

J
Posted By
JJS
Aug 3, 2004
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360
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7
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Closed
This is for the Gimp. http://www.fourmilab.ch/netpbm/pnmctrfilt/

Any pointers to similar procedures to use with Photoshop CS?
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center filter

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R
RSD99
Aug 3, 2004
See

http://www.peimag.com/pdf/pei00/pei0900/farkaspei0900.pdf Nik filters

http://www.luminous-landscape.com/tutorials/panorami.shtml About 1/2 way down "Digitally Simulating a Center ND Filter"

"jjs" wrote in message
This is for the Gimp. http://www.fourmilab.ch/netpbm/pnmctrfilt/
Any pointers to similar procedures to use with Photoshop CS?
J
JJS
Aug 3, 2004
"RSD99" wrote in message
See

http://www.peimag.com/pdf/pei00/pei0900/farkaspei0900.pdf Nik filters
http://www.luminous-landscape.com/tutorials/panorami.shtml About 1/2 way down "Digitally Simulating a Center ND Filter"

Most helpfull!
TN
Tom Nelson
Aug 4, 2004
In article <k%SPc.16803$>, RSD99
wrote:
http://www.luminous-landscape.com/tutorials/panorami.shtml About 1/2 way down "Digitally Simulating a Center ND Filter"
There’s a MUCH simpler way to do it:

1. Do a good white balance and then shoot a medium-gray target completely out of focus. For instance, put a peice of translucent Plexiglas right in front of the lens, disable any autofocus and shoot using the built-in meter. If it’s a digital camera and you normally use several resolution settings, do a photo at each resolution. If you’re shooting film, shoot the film you normally use with that camera.

2. If you shot film, scan it taking care to keep the color balance neutral, at the resolution you’ll use for your final image. You might want to blur the image slightly to minimize film grain.

3. You have now reproduced the light fall-off without reference to any specific photo. In Photoshop, invert the image
(Image>Adjustments>Invert). You have now produced a counteracting image. Save this image for later use.

4. Drag this image onto your photo and set the blending mode to Soft Light. Soft Light lightens and darkens according to the layer’s deviation from neutral gray. Presto! an instant and universal center filter. Unlike the technique mentioned above, there is no need to manually match your gradient to the characteristics of the lens; the lens has done the work for you.

Tom Nelson
Tom Nelson Photography
S
saswss
Aug 4, 2004
In article <k%SPc.16803$>,
"RSD99" writes:
…
http://www.luminous-landscape.com/tutorials/panorami.shtml About 1/2 way down "Digitally Simulating a Center ND Filter"

I would prefer to use a fill layer with a radial gradient. It’s easier and doesn’t take up as much memory and disk space.

—

Warren S. Sarle SAS Institute Inc. The opinions expressed here SAS Campus Drive are mine and not necessarily
(919) 677-8000 Cary, NC 27513, USA those of SAS Institute.
J
JJS
Aug 4, 2004
"Tom Nelson" wrote in message
In article <k%SPc.16803$>, RSD99
wrote:
http://www.luminous-landscape.com/tutorials/panorami.shtml About 1/2 way down "Digitally Simulating a Center ND Filter"
There’s a MUCH simpler way to do it:

1. Do a good white balance and then shoot a medium-gray target completely out of focus. [… snip a good article …]

Thanks very much, Tom. It seems perfectly elegant!
J
JJS
Aug 4, 2004
"Warren Sarle" wrote in message
In article <k%SPc.16803$>,
"RSD99" writes:
…
http://www.luminous-landscape.com/tutorials/panorami.shtml About 1/2 way down "Digitally Simulating a Center ND Filter"

I would prefer to use a fill layer with a radial gradient. It’s easier and doesn’t take up as much memory and disk space.

Tight budget, Warren? 🙂
S
saswss
Aug 5, 2004
In article ,
"jjs" writes:
"Warren Sarle" wrote in message
I would prefer to use a fill layer with a radial gradient. It’s easier and doesn’t take up as much memory and disk space.

Tight budget, Warren? 🙂

Digital image collections always grow to fill the available space.

BTW, if you’re going to use the method Tom Nelson suggested, note that vignetting often depends on the aperture and focusing distance.

—

Warren S. Sarle SAS Institute Inc. The opinions expressed here SAS Campus Drive are mine and not necessarily
(919) 677-8000 Cary, NC 27513, USA those of SAS Institute.

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