Any vignette neutralizer editing tools out there?

Mack

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Been getting some central hotpots in IR images which seems to be normal and more serious for some lenses.

https://www.lifepixel.com/lens-considerations

https://www.edwardnoble.com/hotspots-explained

I've tried to neutralize them in some editors that have the vignetting tools, but they are never even and central to a corner can end up different be different circles of density and roundness depending on image form, lens, f/stop, lens hood, IR filter, step-rings, etc.

Anyone know of some edit tool that one can maybe make a preset from to clean up a dark vignette? Maybe draw a line from center to top of image, corner, and a side and then smooth out the overall tone for a mask or preset to call up later in some editor.
 

RAH

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Anyone know of some edit tool that one can maybe make a preset from to clean up a dark vignette? Maybe draw a line from center to top of image, corner, and a side and then smooth out the overall tone for a mask or preset to call up later in some editor.
I think the best way to think of this adjustment is as a reverse vignette. I mean, usually vignetting darkens the edges and leaves the center untouched. What you want is to darken an area in the center and leave the edges untouched.

So, you can use any editor with a good vignetting tool to darken the edges on a separate layer and then set the mode of that layer to "difference" (to darken the center) and adjust its opacity.

For example, Corel Paint Shop Pro has a vignette tool that lets you adjust the area that gets darkened a lot. So, for example, you can make everything except the very center of the image get a lot darker. If you put this on a separate duplicate layer, you can then change the Blend Mode (where the options are things like Normal, Darken, Lighten, Difference, etc) to Difference, which makes the center be VERY dark (with the outside normal). Then you just adjust the opacity of that layer to lighten and darken that center area.

If want to MOVE the area of darkening around some, the Topaz plugin Lens Effects has a Selective Vignette tool that allows you to move the area of darkness around and change its shape. Again, using this on a separate area allows you to reverse it (using Difference Blend) and adjust its opacity.

If you could supply an image with this problem, I could try it out.
 

RichardC

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You could experiment with a radial graduated filter in photoshop. To do it non destructively, unlock the background layer, load a white layer underneath, then apply a white mask to the original layer and experiment with positioning and density of a white to black radial grad, starting roughly at the centre of the 'good' bit of your image.

Another way would be to increase your canvas size, make a new layer with a radial grad of transparent out to white towards the edges. Then you could move the top layer around if your vignette is uneven.
 

RAH

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I don't think Topaz Lens Effects is available anymore. However, Topaz Studio 2 has a VERY nice vignetting "filter" that allows you to change the location of the vignette A LOT, and you can vary the size, etc. Since you can run it as a plugin (as well as a stand-alone), you can use the same technique I mentioned earlier to have it operate on a separate layer that you then set to Difference to reverse the vignette.
 
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Mack

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I've struggled with the vignetting tools, but seems they are all have issues with the infrared hotspots as to density and size. Then there is the issue of density of the final image that they might cover.

Below is the Olympus 75mm lens from f/1.8 to f/22 off a white card. I used it as it is allegedly the worse of the lot for hotspots with IR filters. Exposure was set to middle of histogram to see the density change and any color from the IR white balance corrections made off it. These are the JPEGS straight out of camera (SOOC). You can see the hotspot form as lens approaches f/22.

All-75mm-apertures.jpg
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I got the idea to make an inverted image of the hotspot, e.g. the f/22 one. When I put it over the SOOC JPEG in a layer and dial it down to 50% Opacity, it corrects the entire image to a neutral gray as expected as shown below.

f22-inverted.jpg
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Inverted image above placed in a layer (in PS) with the SOOC f/22 hotspot JPEG shown below. Thought I was onto something that would get rid of the things.

Inverted-plus-SOOC-JPG.jpg
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However, given the inverted image's density, it affects any photo made and applying it to the photo if I use it as a correction vignette to any shot at f/22.

Maybe a transparent mask would work? But that is eluding me on how to do it, or if any there are any other means of using an "aperture hotspot mask" that would suffice to eliminate a hotspot.

Tia.

Mack
 

Mack

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Here's a SOOC JPEG of a cell tower shot with w 720nm IR filter. Hotspot in middle. Olympus 75mm at f/16.

SOOC-JPEG.jpg
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Using an inverted f/16 mask neutralizes the hotspot, but overall image is now down in density and contrast using the mask.

Inverted-mask-plus-SOOC-JPEG.jpg
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Ideas?

Tia.
 

RichardC

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My earlier post was aimed at mending vignettes rather than hotspots.

You can make a new layer in photoshop, then make a black to transparent radial gradient and overlay over the top, alter the layer density/blend modes to suit. This would yield decent results as a starting point on a monochrome image. It will probably shift colours in most RGB images because you aren't seeing pure colours, you are working with SRGB images which are a reasonable approximation.

You could also try making luminosity masks in Lumenzia (there is a free version) to isolate the bright area, (or manually using channels), then apply a curves adjustment layer to fix tone and colour. It would be hard, to get it absolutely accurate though.

IMHO, it's possible, but will take an absolute age to get consistent results in Photoshop. Taz Tally on Lynda.com does a great set of courses on colour correction for the 'anally retentive' (his words not mine) which demonstrates techniques which will allow you target your colour correction and get an accurate match to another colour elsewhere.

If it were me, and unless I was trying to rescue images that are unrepeatable, I'd be shooting raw, bracketing by a couple of stops at least, getting my highlights and shadows pretty close in ACR, and blending them in Photoshop. Maybe just avoid lenses which cause me the most bother too. Part of the learning curve I guess.
 

RichardC

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Other hurdle is that the hotspot isn't affecting the image evenly.

Had the idea you could use a radial filter in Adobe Camera Raw, keep tweaking until the size/feather was correct, and density/contrast looked right and save as a preset - but the left side of the hotspot appears to be lighter than the right.

Maybe @WhidbeyLVR could think of something?
 

Mack

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Other hurdle is that the hotspot isn't affecting the image evenly.

Had the idea you could use a radial filter in Adobe Camera Raw, keep tweaking until the size/feather was correct, and density/contrast looked right and save as a preset - but the left side of the hotspot appears to be lighter than the right.

Maybe @WhidbeyLVR could think of something?

Thanks Richard. Agree most current vignette fixes do not work smoothly over the entire image with a hotspot in the middle.

I even tried some obscure CornerFix software that was built to address some Leica lens issues without a lot of luck. https://sourceforge.net/projects/cornerfix/

However, I'm wondering if one takes an inverted mask and dials it way down on a transparent layer to mabe 5% opacity, then build it up in multiple layers on the image with the hotspot, if that build-up of layers might work?

My thinking is that the thin starting and inverted mask would have no RGB values in the outer transparent areas where that portion need not be applied to the final image, yet it would apply some density to the center area with the hotspot. Just keep adding on layers since the thinner outer sections have no RGB values even with the extra layers, yet the center should build up and maybe neutralize the hotspot?

Might try that experiment today and see how that multiple thin inverted layers goes.
 

RichardC

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Thanks Richard. Agree most current vignette fixes do not work smoothly over the entire image with a hotspot in the middle.

I even tried some obscure CornerFix software that was built to address some Leica lens issues without a lot of luck. https://sourceforge.net/projects/cornerfix/

However, I'm wondering if one takes an inverted mask and dials it way down on a transparent layer to mabe 5% opacity, then build it up in multiple layers on the image with the hotspot, if that build-up of layers might work?

My thinking is that the thin starting and inverted mask would have no RGB values in the outer transparent areas where that portion need not be applied to the final image, yet it would apply some density to the center area with the hotspot. Just keep adding on layers since the thinner outer sections have no RGB values even with the extra layers, yet the center should build up and maybe neutralize the hotspot?

Might try that experiment today and see how that multiple thin inverted layers goes.

Worth a try. It's bothering me that there may be an extremely simple solution to this.

I had a go at constructing a mask using a white-black gradient. I can get sort of close, but not close enough without a lot of fiddling (ignore the layer with the cross, that's there to help me find the middle of the photo to add the gradient).



Screenshot 2021-02-23 at 16.21.16.png
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Screenshot 2021-02-23 at 16.26.43.png
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Mack

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Worth a try. It's bothering me that there may be an extremely simple solution to this.

I had a go at constructing a mask using a white-black gradient. I can get sort of close, but not close enough without a lot of fiddling (ignore the layer with the cross, that's there to help me find the middle of the photo to add the gradient).



View attachment 875127

View attachment 875128

Interesting with your masking attempt.

I agree there should be an easier way to do this given all the IR converted cameras by sundry outfits and various IR filters in different intensities.

I did get into contact with the tech at Exposure X6 and they are forwarding the IR lens hotspot mess to their design team. Maybe need to draw three radials on the image to figure out how to even it all out based on a blank white card spot.

On1 Photo RAW 2021 has some interesting IR tools in their Effects>Add Filter>Channel Mixer, but nothing to address the hotpsot matter. Seems easier way to do the IR Red/Blue channel swap as in PS.

Now if some smart editing designer would figure out this lens hotspot matter with a simple preset, etc. .... :dash2:
 

WhidbeyLVR

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Here's a SOOC JPEG of a cell tower shot with w 720nm IR filter. Hotspot in middle. Olympus 75mm at f/16.

View attachment 875079

Using an inverted f/16 mask neutralizes the hotspot, but overall image is now down in density and contrast using the mask.

View attachment 875080

Ideas?

Tia.
Other hurdle is that the hotspot isn't affecting the image evenly.

Had the idea you could use a radial filter in Adobe Camera Raw, keep tweaking until the size/feather was correct, and density/contrast looked right and save as a preset - but the left side of the hotspot appears to be lighter than the right.

Maybe @WhidbeyLVR could think of something?
I don't have any artifact-free ideas, but I have fiddled around with it a little bit.

Let me start by having you confirm the objective (roughly):

Objective.jpg
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You are just trying to correct the hotspot, yes? There is also a lens flare from the bright antenna near the center, which I did not try to correct. I wasn't trying to change the color, sharpness, etc. If this result is what you're after, I can tell you what I did.
 
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Mack

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I don't have any artifact-free ideas, but I have fiddled around with it a little bit.

Let me start by having you confirm the objective (roughly):

View attachment 875179

You are just trying to correct the hotspot, yes? There is also a lens flare from the bright antenna near the center, which I did not try to correct. I wasn't trying to change the color, sharpness, etc. If this result is what you're after, I can tell you what I did.

Thanks for the help.

It was just representative as to what the hotspot does in a shot. I used a lot of the sky to show it and the tower as a subject to see how one could correct for the hotspot. I could move the tower to one side in camera, but the hotspot remains centered as in the eight f/stop series of shots above, i.e. the f/16 one second from end. Looks like a bright sun shot that appears in IR shots with the 75mm lens. Gets worse closing it down.

The hotspot does seem to come out a bit blue. For fun, I set the Custom WB four presets in the E-M1 Mark II to four different colors to see if that had any affect on the color of the hotspot below.

First WB was Green Foliage off ColorChecker Passport (RGB=87 108 67) as some seem to like that WB for IR shooting (I printed out a "Green Foliage" WB card since most green vegetation is brown and dead during winter here.). Second shot was a stronger, almost neon green (RGB=70 148 73). Third was a complement (i.e. An amber color RGB=238 145 88) of the "Blue Sky" made off the ColorChecker Passport color. And fourth WB was a "Blue Sky" (RGB=98 122 157) for WB. Actually, the "Amber" (Blue Sky complement color) seemed to be the most color neutral of the four, imho, maybe by it making the Blue Sky a neutral grayish WB . All taken through a 720nm filter and SOOF JPEGS.

White Balance IR 720nm Test.jpg
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I dunno. It's not an easy thing to figure out since it is an f/stop variable, along with the lens, filter, sensor glass, format selected, etc. I'm still thinking there must be a way to neutralize the hotspot, color, and halo by some white wall image at the selected f/stop to make a vignette overlay somehow.
 
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archaeopteryx

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I'm still thinking there must be a way to neutralize the hotspot, color, and halo by some white wall image at the selected f/stop to make a vignette overlay somehow.
A quick approximate hotspot correction in GIMP. A second, larger radius one should get most of the residual.
GIMP 720 nm cell tower vignette.jpg
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If you don't want to write code the easiest option that's immediately occurring to me is compiling a library of multiply layers across lenses and f/stops. Another option that's a little more involved is a preset library.
 

bargainguy

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Can I dial this question back a bit?

I've been shooting IR for 40 years. Hotspots, bright areas, weird flare....nothing new.

Very few lenses are designed to properly transmit IR (and/or UV, for that matter) over normal spectrum. So the lenses we're using were never designed for IR transmission.

Results are completely unpredictable. I can't tell if a lens is going to be stellar for IR without actually trying it.

The way I mitigate IR reflection issues is to carefully select lenses, then pay particular attention to aperture.

Some of the hotspot effects are exaggerated at certain apertures, so I avoid shooting at those apertures.

Some of the bright area effects are also exaggerated at certain apertures, and especially by the direction of the light. I had (and sold) a Rokinon 50/1.2 MFT that was excellent at IR transmission, but produced such odd stray effects that I no longer wanted to work with it. Great in one area, horrible in another.

If you shoot Nikon at all, Bjorn Rorslett's site is absolutely invaluable for reviews of individual IR lens performance: http://www.naturfotograf.com/lens_surv.html

Whenever I get a lens, I test at all apertures in IR, preferably with bright light at obtuse angles. That way, I know where the hotspots are, where the weird flare areas are, etc. Doesn't always mitigate shooting issues, but it's a start.
 

Mack

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Had a bit better luck by doing the inverted white card at f/16 and dialing it lighter with Opacity and putting it on a transparent mask, then copying it with multiple layers to build it up in small 5% layer opacity steps to match closer to the image.

It didn't totally eliminate the IR hotspot's bluish color issue, but the old "NIK Viveza 2" tool in PS, or the "Local Adjustments" tool in DxO Photolab 4, took care of the color issue. In fact, the "NIK Viveza 2" or the "Local Adjustments" tools in those two programs might just be the answer as they restrict the working area to a small spot than the entire image as with some vignetting tools.

2238112-Test3.jpg
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Still, there must be an easier and faster way.
 
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Mack

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I found an editing program that may address the hotspot matter better than most. It's a slimmed down version of RawTherapee that includes a mask feature called ART. It has a very adjustable Mask feature that can be tuned to the lighter area of the hotspot and any residual flare as well.

Website: https://bitbucket.org/agriggio/art/wiki/Home
Downloads: https://bitbucket.org/agriggio/art/downloads/

Below is a link to an instructional video on the use of using its mask on a doll. No audio, and it takes some time experimenting to understand it. The newest version 1.8.2 has three color wheels (Highlights/Gain, Shadows/Lift, and Midtones/Gamma) that can dial back the hotspot's luminance, as well as color on top of the wheels (Saturation and Output). I found those a great help in the mask. Some video's names are changed like " ∆ Color" which is now called "Color similarity mask." It works in HSL which is close to a L*ab and won't influence colors and bleed too much as with a RGB editor does with luminance.

The adjustability of the "Mask" feature is demonstrated on a doll's head:
https://bytebucket.org/agriggio/art...?rev=31f577890484c6325fa77c08bafc6082303b85bc

More on ART mask: https://yap.bozart.eu/articles/art/area/index.html
 
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RAH

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That looks very interesting, although I have to say that as a RawTherapee user (it's my main RAW program), it's scary enough using RT, much less dealing with a "fork." I suppose if it got popular enough to become established, it would be good, but these things come and go, I think. :)
 
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