Purple Fringing - Chromatic Aberrations

[IanCD]

My understanding of this is all 'second hand', from various sources including the Adobe article I posted a link to above and a very detailed technical discussion at Photozone which highlighted a number of potential mechanisms for purple fringing (PF), although it didn't reach an agreed, definitive conclusion as to the cause.
It does seem to be agreed that 'Purple fringing' and LoCA (or 'bokeh fringing') are two different phenomena, with LoCA occurring in out of focus areas and PF at harsh contrast transitions including the focal plane.
Some of the discussion at PZ is worth checking out for if you're interested enough in the technical stuff..!
Ian

[Brownbear]

Thank you. I will check out that program... My ducks are still purple! Even if I put the aperture at F8. And if I use a smaller aperture number or increase the shutter speed the photos are too, still too dark (pitch black in fact)

Anyway, I thought I would share another duck photo just because they are cute.. And hopefully one day, I will have a good duck shot to post.




And a great (real bad example of the fringing) when I try to shoot the parrotlets


I would like to ask why I only see the fringing when I try to shoot the birds against the sky?

Thank you everyone

[IanCD]

I would like to ask why I only see the fringing when I try to shoot the birds against the sky?
Thank you everyone

Hi Christina,
It's really difficult to see much detail in that last shot... other than the fact that all the birds are blue-purple tinged...
The reason for purple fringing being seen when you shoot against the sky is that you're getting the harshest contrast transition possible that way... dark birds against the bright sky.
The birds are so small in the last pic, they're pretty much all edge, so I think the purple fringing may cover a high proportion of the dark surfaces... is it possible for you to post a tight crop of just the birds, or some of them..?
Ian

[Brownbear]

Hi Ian,
Thank you for the explanation.

Here they are cropped.

As is from camera



Smart fix in elements



F 5.6 ISO 400 S 1/2000 sec

[Brownbear]

I tried the DXO and it is definately helpful, especially when you consider I am new to editing photos and don't know what I am doing...

Tried it on the parrotlets
Before

After



And on a duck (shot at A 10 to try and avoid fringing but still experienced some, and that is why the photo is dark and the shutter speed I used was too slow)


So now I will try to shoot the ducks at A 5.6 so they are lighter and sharper, and see if I can fix the fringing and chromatic aberrations with DX) But the ducks are not so common now, but I though I would post so others could see that the DX program does help.

[Brownbear]

Just to let everyone know that I finally got a half decent shot of the ducks (actually a duck)...



A 7.1 S 640 ISO 800
Sony Alpha DSLR

it was cloudy, so perhaps that helped.

Thank you everyone!

Actually maybe he is better cropped closer (A big smile)

[IanCD]

Just to let everyone know that I finally got a half decent shot of the ducks (actually a duck)...



A 7.1 S 640 ISO 800
Sony Alpha DSLR

it was cloudy, so perhaps that helped.

Thank you everyone!

Actually maybe he is better cropped closer (A big smile)

Yes, you did..! Congrats after all the effort... well done..!
Ian

[Brownbear]

Thank you so much Ian!

[Brownbear]

I promised a better photo of the parrotlets when I managed to take one so here are a couple. However, when enlarged you can still have chromatic aberrations/purple fringing and I think this thread is too, long so I will post a new thread on that, which hopefully other folks will learn from, too.