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I cant honestly answer that. That is way over my head. Lol. I’m even notice this not to the extent of birds but whenever doing macro shots of red roses that the camera struggles to focus at times but again, maybe it’s just nature of the beast or I’m an idiot lol.
htmlcolorcodes.com
As I understand it the linear and cross point AF sensors really focus in gray scale but yes those that sit behind red filters would have that grayscale light attenuated. Still, focus is at edges, often the edges between the color of the subject and the darker eyes so there should still be a grayscale difference on those edges.
That definitely makes sense and like I said no other shade, no matter how vibrant seems to have an issue. In fact, from my experience every mirrorless camera I’ve used seems to stick on blue subjects like glue.It is interesting. Every red is not only red though. If you hover the mouse in lightroom you can see the rgb components of what is below the cursor. Maybe there is a threshold of green and blue needed.
Shades of Red – HTML Color Codes
The many shades of red are some of the most evocative colors out there, both psychologically and linguistically. Red is a color that lends itself to striking visuals, which is clear in the names of shades like blood red, crimson, imperial red, cardinal red, chili red, and vermilion.
Makes sense to me. It also seems worse when the bird is starting directly forward which could be why the hypothesis you present about edges hold true.
And there's also this mention recently
dprevived.com
Very interesting.And there's also this mention recently
"....One thing I haven't seen written about the Sony A1 is the bird color/eye color issue. Some combinations of bird and eye color focus extremely well, others not so much, some not at all. This clearly has to do with the way Sony trained the ML/AI module. Others have trained theirs differently. I notice, for example, that Nikon seems to favor two bird positions (upright stationary and full flight). An unusual bird/wing shape/position will sometimes cause the Z9 to put focus in the wrong spot, though generally not off by a lot."
What's going on with Nikon?
Started by tommy on April 21, 2023 in the Nikon category. 126 replies, last one from May 3, 2023.
This might also be linked (perhaps confound) the horizontal versus vertical aspects of AF reliability with MILC AF. Just a suggestion
That’s just crazy! Neither one of mine have done that.
That’s interesting, the cardinals there look almost orange.
Steven, I don't have any photos to share because I deleted the blurry ones. Yesterday there were a couple scarlet and a couple summer tanagers along our hike. I had a devil of a time getting my Canon R7 to focus and Leslie had trouble with her Sony RX-10. Ultimately, I had to manually focus and once I nailed it with manual, the tracking would hold onto the bird but initial focus was hard on both cameras.
I’m glad you posted this because this is absolutely happening and happens often. It did it with all five Nikon mirrorless cameras I owned and now three Sony bodies. There are times even 20 feet away from a vibrant male cardinal, it will not acquire focus no matter what until it’s helped manually. As the colors fade into the fall due to molting the problem doesn’t happen. The summer tanagers are the worst imo, especially if they’re surrounded with green such as the image I posted earlier. This never ever happens with any other color.
I'm not sure exactly how the AF on the Mirrorless works but something I thought of is it could be the lack of contrast between red and green as the camera sees it. I've attached a black and white version of one of the Summer Tanagers I shot yesterday. This exact shot gave me fits trying to get the AF to pick it up. I finally switched the camera into manual focus and grabbed the shot. The bird sat in this spot for about 30 seconds singing its little heart out.
Very interesting
here is the same shot in color. I'm not sure if the contrast or lack thereof in the non-color version has anything to do with it or not. Would be interesting for one of the engineers to chime in.
This is exactly the scenario that causes the worst problems
Jeff, I guess you and I are anomalies because we seem to be the only ones on the face of the Earth that are experiencing this lol
I don't remember if Thom says how he knows, but I'll guess that using something like RawDigger on raw files you can identify which pixel rows are used for PDAF and what are the corresponding Bayer filter colors.
As I said in my first post I am not sure exactly what the processor sees in the AF. I just noticed the contrast difference between red and green was quite low and when colors were removed so that they are seen as shades of gray there is very little contrast.
Thank you -- since the same type of sensor is in the A1 and the Z9 (well as far as I know) then one could reasonably expect to see the same results in a Z9 as an A1 with RED subjects.
