Fringing

Kinkajou · October 30, 2011

Any ideas how to correct this in post or how to avoid this in the future? It seems to be limited to the white clothing against something darker...

Unfortunately, Smuggy is down so I have to include the photo as an attachment... I'll replace it with a link once Smuggy is back online.

Thanks!

angevin1 · October 30, 2011

Gees, I don't see what you're referring to?? Where in this image above?

Matthew Saville · October 30, 2011

I can't see it in that low-res image display, but are you referring to the weird halo effect that you get when boosting both the highlight recovery AND shadow recovery in Lightroom / Bridge / Aperture? That is just a side-effect of cranking your dynamic range, and to remove it all you can really do is carefully clone it out.

Or, is this a relatively un-edited image? Another thing that can cause this is cranking the clarity slider in Lightroom. That can cause weird things to highlight edges.

Once SmugMug works for you again, share us some 100% crops of the issue. :-)

=Matt=

Kinkajou · November 1, 2011

Smuggy is back, so here is a better version...

The area that is really bothering me is the part of her dress that is showing above her arm and his shirt against the armhole of the vest. It seems to be restricted to bright against dark. This was with a 70-200/2.8 btw, I don't know if that matters...

I will go back and check what I did to the original image to see how that might affect things... I definitely did not use the clarity slider, but I'll have to check on the fill/recovery.

tenoverthenose · November 1, 2011

That's a problem with your lens. But don't worry, just about every lens made has that same problem

It's chromatic aberration rearing it's ugly head. You should be able to help it out a bit in either lightroom (Lens Corrections) or photoshop fairly quickly.

High contrast in bright light at open apertures will show this lens flaw.

Kinkajou · November 1, 2011

tenoverthenose wrote: »

That's a problem with your lens. But don't worry, just about every lens made has that same problem It's chromatic aberration rearing it's ugly head. You should be able to help it out a bit in either lightroom (Lens Corrections) or photoshop fairly quickly.

High contrast in bright light at open apertures will show this lens flaw.

That sounds spot on... good to know.

NeilL · November 1, 2011

I'm not sure I see what you mean. However, fringing and CA can have a number of reasons for occurring and can show in a few different ways. In this image, as well as the high contrast edges, the angle of the lens to the subjects could also contribute to aberration. Some of the global software fixes can fix one form while inducing a different form in the same area of the image. The latest Lr fix is good, just carefully examine its effect on a particular image. In the case of your image here a good result could be got very quickly in Ps by using multiple layers of Hue/Saturation and desaturating one at a time the hues of the fringes, and brushing them into only the affected edges at >100% on a negative mask.

Hand metering the exposure, using the lens sweet spot, nailing focus, stabilising the lens, placing the subject in the centre of the frame, avoiding angling the lens to the subject, avoiding cropping in post - all can keep fringing at bay.

Neil

Matthew Saville · November 1, 2011

Still can't see the original size or a 100% crop, that would be helpful. Also, consider my questions about the processing of shadows / highlights / clarity.

If it is the *purple* you are talking about, and especially if the image was shot at f/2.8 or f/4, then yeah it's just fringing that happens in harsh lighting conditions. Stop down, or use Lightroom's auto-profile and it will usually do a pretty good job of removing it.

As Neil also mentioned, it can be exacerbated if you mis focus just slightly. If you're at a low angle and you focused on their faces, the dress / vest will be slightly forward of perfect focus, which will bring out purple fringing or other chromatic aberration issues. Or, if you're getting this issue with the area you WANT to be in focus, then maybe the lens needs a little calibration. Get on a tripod, focus on a brick wall, crank up your in-cameras sharpening, and play around with the AF microadjustment to see if things get better or worse...

=Matt=

divamum · November 2, 2011

Go to (I believe) finishing school, and check out a few discussions on how to fix it in post - I know I had issues with it and posted about a year ago and got lots of suggestions, plus there are a tone of older threads there with suggestions too. ETA: if it isn't in Fin School, check the Technique forum.

One thing which can help if the lens correction adjustments in LR aren't enough is to go into PS, select purples/magentas in the hue/sat dialog, reduce saturation on those and then mask out the rest of the layer You can do something similar in LR's colours by reducing purples/magentas as necessary too (and it doesn't look like that would affect much else in the shot you've posted).

It's a pain, but it is minimizeable!

zoomer · November 2, 2011

May not help but...don't worry about it...nobody will see it but you.
I don't see it even after you pointed it out.
What I do see is there seems to be an overall blueish green tint to the photo. Get your whites white and the fringe you see may disappear.

Kinkajou · November 2, 2011

1 - Yikes! Do the colors look off (i.e., blue/green hue per zoomer's post) to anyone else?

2 - Thanks for all the advice, guys! This was definitely shot wide open and the areas with the fringing were in front of the focal plane. The target focus areas show no fringing, so that's good. For some reason I totally didn't think about fixing it with layers/masks in PS. Duh.

I forgot to check my LR adjustments last night, so I'll try to do that today.

Thanks again! I love DGrin

Fringing

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