Problem Solving

[bisso7]

What did the histograms look like (not the camera histos, but the PP histos - were they blown out at all)?

The PP histograms were all blown out, not surprisingly, except when I applied the negative stop EC.

I guess what I am puzzled about is why this particular issue with THIS lens? I've shot this scene in past times with my EF 55mm - 250mm f/4-5.6 IS II telephoto and did not experience this purple fringing. Also, however, I understand that my subject was bright white in relatively harsh lighting, as I did the re-shoot at precisely the same time as the original.

Regards,

Jeff

[Glenn NK]

Jeff:

It would seem then, that if the image wasn't clipped, then the fringing would not appear at all?

After reading the Photozone test, I'm not particularly inclined to blame this lens.

Anyone else have any thoughts on this?

Glenn

[Stagecoach]

I guess what I am puzzled about is why this particular issue with THIS lens? I've shot this scene in past times with my EF 55mm - 250mm f/4-5.6 IS II telephoto and did not experience this purple fringing. Also, however, I understand that my subject was bright white in relatively harsh lighting, as I did the re-shoot at precisely the same time as the original.

Regards,

Jeff

Jeff,

I suspect you could only make any basic comparison between how each lens dealt with the situation based on ensuring you had equal exposure results (not just settings) under the same light conditions with each lens.

Grahame

[William W]

Jeff:

It would seem then, that if the image wasn't clipped, then the fringing would not appear at all?

After reading the Photozone test, I'm not particularly inclined to blame this lens.

Anyone else have any thoughts on this?

Glenn

My observations remain as articulated in Post #11, specifically referencing the second pair of images as posted ‘bottom right hand corner’, where the line of the window and the window-sill appear not to be overexposed at section where the fringing occurs when the lens is used at F/1.8 and the second image in that pair shows that the fringing is substantially less, when the lens is used at F/5

And I remain of the same opinion as per post #8

The extreme Purple Fringing (CA) is as result of (as Boab describes) - intrinsic to the lens & the aperture that was chosen.

I’d add that the CA is exacerbated in this particular shot by the extreme reflective white of the Object and also the strong harsh light on it.

That is to say that this lens (and mostly all fast primes and seemingly all fast prime that I have used) exhibit this intrinsic trait and that the aperture used is the governing factor, BUT in this particular example in Post #1, the extreme over exposure at the area of white flowers exacerbated that Fringing.

WW

[William W]

. . . I guess what I am puzzled about is why this particular issue with THIS lens? I've shot this scene in past times with my EF 55mm - 250mm f/4-5.6 IS II telephoto and did not experience this purple fringing.

As answered by Boab in Post #7 and myself in Posts #8, #11 and #24.

The issue is intrinsic to (many) Fast Primes, when used at their maximum aperture.

And in your example, the effect was exacerbated by the overexposure of the white area in the shot.

WW