I have just struck an unusual problem with cross-hatching appearing on plumage, something that is definitely not part of the bird's actual plumage. See attached photo. I assume it must be some automatic response to the reflection setting. I have discovered mention of the problem on the internet by the wildlife photographer, Tony Whitehead (https://www.tonywhitehead.com/wildlight/archives/10559). According to Whitehead, It apparently affected Nikon 850s, and is related to whether a particular camera has an anti-aliasing low-pass filter (AAF) installed. He did suggest a "fix" involving setting Moire to +100 and reducing texture, clarity and dehazing, but when I tried this I began to lose necessary detail.
Has anyone else experienced the problem and has suggestions, that is, apart from buying another camera?
I am using a Nikon Z7ii, which apparently does not have AAF installed.
Michael

Hello Michael,

I am not seeing any moire, but I am seeing some bright bands on the underparts caused by sunlight reflected up from the ripple on the water surface. Is this what you are asking about, or is there something more that I have not noticed?

Kind regards, Ian

Dear Ian,
Thanks for this suggestion. I did consider that the horizontal ones might well be reflections from the ripples but was less sure about the intersecting ones at right angles that created the crosshatch effect. On the other hand, since the ripples on the water are circular, perhaps there is some optical way in which they create a more straight line effect on the curved surface of the bird's underparts. Certainly using the Moire adjustment made no difference to the crosshatch effect, so it may just be reflections after all!
Regards,
Michael

I agree with Ian. I think the relatively low angle of the sun to the left of the image is reflecting off the ripples giving the bright lines in the bird's plumage. I am not seeing any 'cross hatching'. I think the apparent vertical 'lines' you are seeing are simply the variation due to the way the light is catching the layers of feathers in the white breast. These slight variations in brightness seem to follow the natural line of the edges of the feathers, and as a result seem slightly scalloped. There is no apparent moire although with the file size reduction for the post, as well as the level of noise in the file, it would probably be difficult to see anyway.

I would always be wary of apparent problems that spring up in only one set of files from one shoot in one location. If you have a major problem with a lens or camera it should show up consistently. You shoot a lot of shots of waterbirds but this seems to be something you have just noticed. Much more likely it is due to light or other local issues shot rather than equipment. I doubt you need worry about your equipment.

regards
Simon

Dear Simon,
Thanks for this reassurance. I am relieved that I don't have an equipment problem. I did check some other photos of birds in pools I took on the same day, also with ripples, and saw reflections on the birds' plumage but without any apparent crosshatch effect. It probably was just a very specific sunlight/circular ripple effect with this bird being at a certain angle.
With much appreciation for Ian's and your assistance on this.
Regards,
Michael

The fact that the unusual pattern is directly mirrored in the reflection tells me is is an act of the light rather than a digital flaw.