my lens Nikkor 24-85mm F2.8-4.0 seems to have a sluggish autofocus, especially for far range between infinity and 7ft. The AF is fast if swinging from far to near and vice versa (e.g. when I hold the hand before it and take the hand away in the video) but quite hesitant if focus on different targets at the similar distance. Could you tell by looking at the video below whether it's sluggish with this particular lens or it's symptomatic for the model
Sometimes it has even problem to focus but oscillates between 7 ft and infinity for a while on the same target, in which case I have to swing the camera away then back to get it focused; light condition was OK, not dim lit. The focus issue with slugginess and oscillating causes of course to miss fast action e.g in animal photography, they don't wait for you most of the time
The AF 24-85mm f/2.8-4D IF is fully compatible with your D50. What ambient lighting conditions are you shooting in when the problem occurs? Are you using a good AF target with enough contrast? Good Luck and Enjoy your Nikons!
I took the lens outdoor this morning under bright sunlight, the targets are various objects in the gardens such as chairs, trees, flowers. The slugginess is less but still not as fast as I expect from such an expensive lens. As mentioned AF is satisfying if targeting objects of big difference of distances but sluggish for targets in same range, or even for the same target when half-pressing the shutter button again, or more exact I had the camera on the tripod aiming at a chair 20 feet away, every time I half-press the shutter button, the AF on the lens tries to focus again in slow motion although the camera is not moved, the aiming not changed.
Edit: of course there is the focus lock to prevent the AF to re-focus.
>Hi RodW, was it with the same lens model? No, I just slipped my 50mm f1.4 onto my friend's body to take a few snaps of their child for them. Whatever it was set on when I picked it up was really slow so wondered if it was the face recognition or something adding to focus time. I Can't really remember which mode I changed it to, would have been A or P and it came good so I thought it was worth a try for you
Keep in mind that your 24-85mm has a screwdriver type AF drive that is powered by the AF motor built into the camera body. Given that the D50 is an entry level model, the AF motor has less torque than the AF motors in the Pro bodies. Add to that the size and weight of the lens elements that must be moved to focus the lens could be the root cause of your problem with the AF speed. The kit lenses are smaller and lighter so there is less mass for the AF motor to overcome. Since the Equipment tab in your User Profile is blank, I don't know the other lens or lenses that you are comparing the 24-85mm to. Good Luck and Enjoy your Nikons!