I hope you got the good replacement. If there's no halos/vignetting from Nikon Z 100-400, i'd be happy to jump ship :D January 31, 2023

You meant vignetting at >200mm even at f8 or smaller? Holy crap! I had Sigma 100-400 before i started JP here. Let me throw my old sigma photo into our equalizer here to see what happens. btw, we spotters adapt and always find good spots :) January 30, 2023

In fact, f11 will still have visible vignetting. However, this seems to be the characteristic of all large magnification zoom lenses, and this is also a full-frame lens. In this case, SIGMA has achieved good sharpness and good resolution. I am still very satisfied with it. I have used SIGMA 100-400 before. You can see it in Exif of my previous pictures. This lens is newer, with very good optical quality, and the gradual halo is not obvious, but it will produce a circle of bright light in the picture, which looks like an over-repair of vignetting, but in fact this is the problem of the lens itself. (This seems to be the characteristic of all 100-400 lenses. Except for Nikon's new Z 100-400 S, all 100-400 lenses have this problem, including SIGMA, Tamron, Sony GM.) And because the focus range is not large enough, I still decided to replace it :D January 30, 2023

SIGMA 50-500mm working well with your Z5 eh :) only 135mm? Must a good and close location :) January 29, 2023

This location is very good. You don't need to buy a high-priced telephoto lens. You only need a standard zoom lens to shoot (for example, 18-135, 24-70). Unfortunately, it has been demolished. In addition, the SIGMA 50-500 is really a good lens. The only drawback is that its dark angle is very serious. In the focus segment larger than 200mm, I need to add a lot of process to repair it. But it is very cheap, and the picture quality is excellent, so I like it! January 29, 2023