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Full Version: Cyan fringing? (Sigma 105mm F2.8 DG DN MACRO | A)
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This photo is a crop from a 1:1 photo taken with the Sigma 105mm F2.8 DG DN MACRO | A and a Sony a6600, at ƒ5/6. The fluff looks partly whiteish and partly with a cyan cast. The butterfly is a Melanargia galathea and, looking at the specimen images in Wikimedia, I don't see any cyan hue, so I suppose it's a kind of fringing. Can you confirm? It seems no tool in Capture One is able to remove it.

[attachment=206]

Note that the intensity of the cyan cast is a bit reduced in the attachment as an effect of JPEG compression.
I've to admit that I'm not totally sure what you are referring to here. Is it about the bluish hairs in the dead center?

If so, I sort of doubt that this is lens-related fringing.

Chromatic aberration can indeed appear in the form of purple/red/blue/cyan/green halos - but that's not close to the center (unless the lens has an issue).

It's probably just related to the reflective characteristics of these hairs.

davidmanze

I'm seeing magenta not cyan .......... ie purple fringing?
Reposting a smaller section that doesn't need lowering JPEG quality.
Actually the section is from the center, so it shouldn't be a lens defect... but I'm still puzzled.

davidmanze

(06-12-2023, 07:43 AM)stoppingdown Wrote: [ -> ]Reposting a smaller section that doesn't need lowering JPEG quality.
Actually the section is from the center, so it shouldn't be a lens defect... but I'm still puzzled.

Still seeing more purple than blue ......
Could you say exactly what the lens model is and approx age ?  ...... (I had a Sigma 105 macro screw drive lens)
 purple fringing can turn up anywhere in the frame including the center when there is strong contrast ... I am no expert as we all know, but it doesn't follow the same rules as standard CA ... it doen't look too bad and the fact that the butterfly is black and white should make it easy to correct with the adjustment brush and de-saturate colour...... 
  

OT ...... I just had to order another printer, the Epson ET-2810, as my previous printer's  reliability (Epson ET-2710) was curtailed by a drunken dancer falling on top of it! .... 
  motto: 
    ....... keep printers out of reach of drunken dancers .....
Problem solved: it's the butterfly.

https://www.monaconatureencyclopedia.com...-galathea/

Images from Wikipedia don't show that cyan/blue cast, but at this point it could be a specimen variability.

davidmanze

Ha ha !!
Eh... Preserving the true colours of subjects such as flowers and insects is not easy...

davidmanze

(06-12-2023, 11:42 AM)stoppingdown Wrote: [ -> ]Eh... Preserving the true colours of subjects such as flowers and insects is not easy...

     Yeah, it has the whole world running round in circles ....... Smile