amfoto1 Loc: San Jose, Calif. USA

Birds in flight are one of the most difficult subjects to maintain in focus. It is not uncommon for there to be a lot of "misses". That happens to us all... We just don't share the out of focus images! There's a little trash can icon on my computer where I deposit my OOF images.

With DSLRs and many mirrorless, you will get the best results using the fewest AF points possible. A single AF point kept "on target" by you... kept precisely where you want the camera and lens to focus... will always give the most in-focus consistency.

The problem is, that's not easy to do! Especially with small, fast moving subjects like BIF. So often it's necessary to activate a group of AF points... But then there is increased risk of the camera and lens focusing on a closer wingtip or jumping to a background or something the subject momentarily passes behind.

The more active AF points, the larger part of the image area they cover, the greater the risk camera and lens will focus somewhere other than where you want.

There are also other factors...

- Camera and lens AF performance is determined by the systems in each. Some lenses focus faster or slower than others due to the type of focus drive or the "throw" designed into them. For example, macro lenses are often deliberately designed with slower "long throw" focus that emphasizes accuracy over speed. Generally speaking an "ultrasonic" focus drive motor in a lens is faster than a "stepper motor" which in turn is faster than a "micro motor". In some of their most advanced/pro-oriented cameras Canon has a dedicated chip running the autofocus, while their other cameras use a single processor to handle everything: focus, metering and images (I don't know if other manufacturers do this, but there is no doubt that all make more advanced cameras and lenses with higher performance autofocus).

- Max lens aperture can be another key factor. It determines how much light is available for the AF sensors to work with.

- DSLRs commonly "split" the light that enters the lens, sending some of it to the optical viewfinder, while only part of it is directed to the AF sensors. It is common for mirrorless cameras to be able to autofocus in lower light conditions because their AF sensors are embedded directly in the image sensor and there is no mirror redirecting a portion of the light away from them.

- Ambient conditions have a big effect, too. Not much you can do about low light levels, unless there is some form of AF assist available (such as some flash provide). Subject contrast and detail can be a factor, too. A very plain surface with no detail at all is difficult to focus upon. AF looks for edges and contrast, struggles when there isn't any or very much to work with. A more distant subject being photographed through a lot of atmosphere also may mess with autofocus.

- Your focusing skill is another key factor. You'll do better with more familiar and predictable subjects. Practice, practice, practice! Your AF system set up also may be important. You'll need to use a continuous form of AF (I believe you are) and you might want to experiment with Back Button Focusing (if not already using it). There also may be tweaks you can do in your camera's menu. For example, I can set some of my cameras to emphasize focus over shutter release, since out of focus images are of little use to me (a photojournalist might do the opposite in certain situations). I also can adjust the "stickiness" of the AF system... how quick the AF is to jump to another object either behind or in front of the subject.

I would wager 98 out of 100 "camera issues" are no fault of the camera (or lens) at all. They are "user issues". The person behind the camera is doing something wrong or just has unreasonable expectations.

That said, the most advanced mirrorless camera AF systems are pretty amazing. Among others, the Nikon Z9, Sony A1 and Canon R3 autofocus systems are able to identify and lock onto subjects with a high degree of reliability. There isn't a "mirrorless D500" yet... but I would bet there will be some day. It has been such a popular DSLR, surely Nikon has hopes of repeating that success in their Z-system. For now use your D500 and practice, practice, practice... but watch for a mirrorless version of the camera in the future and grab one if you can!

RScolspr. Loc: Colorado Springs co

Thank you so much for your advice it me that is the problem Appreciate you amfoto1.

CHG_CANON Loc: the Windy City

So, you're not going to post any examples?