How to correct the aberrations?

A forum to ask questions, post setups, and generally discuss anything having to do with photomacrography and photomicroscopy.

Moderators: Pau, rjlittlefield, ChrisR, Chris S.

Adalbert
Posts: 1329
Joined: Mon Nov 30, 2015 1:09 pm

How to correct the aberrations?

Post by Adalbert »

Hello everyone,
Does anybody know if and how the aberrations can be corrected by the software (but not by any eyepiece) ?
I have just tried to remove the chromatic aberration with PS but without any success.
What about Piccure+ or Topaz Clarity ?

Enclosed you will find a photo taken with my low-cost lens:
http://www.photomacrography.net/forum/v ... highlight=

Image

BR, Adi

ChrisR
Site Admin
Posts: 8597
Joined: Sat Mar 14, 2009 3:58 am
Location: Near London, UK

Post by ChrisR »

Something like this any good?

Image
Chris R

g4lab
Posts: 1434
Joined: Fri May 23, 2008 11:07 am

Post by g4lab »

How did you do that? Adjust the magnification of the separate RGB channels?

JW
Posts: 168
Joined: Wed Feb 23, 2011 7:38 am
Location: New Haven, CT, USA

Post by JW »

Look s like a PS removal of cyan and magenta channels to me, as whats left behind in the strongly cyan areas is grey. Would like to take the next step and "move" the cyan and magenta pixels into their proper place in the image.
It's not what you look at that matters, it's what you see - Henry David Thoreau

ChrisR
Site Admin
Posts: 8597
Joined: Sat Mar 14, 2009 3:58 am
Location: Near London, UK

Post by ChrisR »

:D
Not quite right, and less complicated.
Any more guesses?
Chris R

MaxRockbin
Posts: 185
Joined: Sat Nov 08, 2014 11:12 pm
Location: Portland, OR

Post by MaxRockbin »

To my eye... you can get to the ChrisR corrected image with:

Photoshop->Camera Raw->Lens Corrections->Color
Defringe (to taste). I think I got to this look with
Purple Amt = 5
Hue = 15/67
Green Amt =3
Hue = 29/88

Though without knowing the bug, it's hard to know whether the eye should have some blue or not. This would mostly take it out.

What's the bug?
If your pictures aren't good enough, you're not close enough. - Robert Capa

Adalbert
Posts: 1329
Joined: Mon Nov 30, 2015 1:09 pm

Post by Adalbert »

Hi MaxRockbin,
The lens corrections of the PS I have already tested :-( and this is a ladybird :-)
BR, Adi

Adalbert
Posts: 1329
Joined: Mon Nov 30, 2015 1:09 pm

Post by Adalbert »

Hello Chris,
Yes, it is a little bit better :-)
BR, Adi

ChrisR
Site Admin
Posts: 8597
Joined: Sat Mar 14, 2009 3:58 am
Location: Near London, UK

Post by ChrisR »

This was very simple. Doesn't recover detail, but on areas of bristles etc can be OK.

Put image in Photoshop Layer 1
Copy to Layer 2
Layer 2, Filter>Gussian blur. Set amount to suit - try 3, try 30...
Layer2, set Layer mode to Color
Done


You can add a Layer mask to Layer 2. The CA will get dragged towards not grey, but the average of the area, because it's blurred.
and change its transparency
and change the colour(s).

You can derive a mask from a high-pass filtered version of the image, and use that for the "color" layer mask, to apply the effect primarily to edges.

If you've done all the CA correction you can in Raw, or in Tiff/Jpeg stacked output, and have some CA left, it can be useful.

It may not be "correct" but it's less offensive than seeing coloured edges, I think.

Edit
Same thing, but it's easier if you change the order.
Duplicate the layer, set the new layer Mode to Color
(you see nothing changed)
THEN Filter>Blur>Gaussian Blur, and you can use the slider/increment/decrement to see the effect "live"

Search words - chromatic photoshop correction fringes
Last edited by ChrisR on Tue Jun 05, 2018 8:42 am, edited 3 times in total.
Chris R

Charles Krebs
Posts: 5865
Joined: Tue Aug 01, 2006 8:02 pm
Location: Issaquah, WA USA
Contact:

Post by Charles Krebs »

Chris,

Extremely useful technique... thanks for posting this.

For whatever reason, the "standard" global CA tools that are frequently useful for regular photography are often marginally effective for some of the aberrations experienced with situations like seen here. This works surprisingly well.

MaxRockbin
Posts: 185
Joined: Sat Nov 08, 2014 11:12 pm
Location: Portland, OR

Post by MaxRockbin »

That's a great idea ChrisR!

I've been doing pretty much exactly that with Zerene stacker DMap and PMax stacks - using the DMAP (maybe slightly blurred to lessen artifact effects) as a color blended layer on top of a Pmax layer.

That way you get the nicer colors (usually) of the Dmap stack on top of the Pmax (Typically sharper/less artificated) luminensce layer.

But it never occurred to me the same technique could reduce chromatic aberration fringing.
If your pictures aren't good enough, you're not close enough. - Robert Capa

ChrisR
Site Admin
Posts: 8597
Joined: Sat Mar 14, 2009 3:58 am
Location: Near London, UK

Post by ChrisR »

I'm not sure, but I think it was Craig Gerard who brought it to the forum :)
Chris R

JH
Posts: 1285
Joined: Sat Mar 09, 2013 9:46 am
Location: Vallentuna, Stockholm, Sweden
Contact:

Post by JH »

Thanks!
Very useful technique – would be nice to have in the FAQ section.
Regards Jörgen

Post Reply Previous topicNext topic