I have a Canon T8i and a 55-250mm lens.
My camera is set at Movie Servo and continuous autofocus.
I have a problem with autofocus at long telephoto distances. If I aim the camera at something long distance, it focuses easily, but if I shift the camera to something closeup, my lens will slowly focus on the subject, but if I then lift the camera and aim at something far away again, the lens refuses to focus. I have to start zooming back out before it will begin to focus on that far away subject.
Just for the heck of it, I slapped a 50mm prime on my camera, and the movie servo worked flawlessly.
I did a little reading in the manual this morning, and read that movie servo on my camera doesn't work when zooming or if the image is magnified.
Even though I wasn't technically "zooming", I think my camera has a problem when "zoomed". The servo mode kicks in when I start zooming back out.
I also read that some cameras have a movie servo sensitivity scale. Mine isn't that sophisticated. It's either enabled, or disabled, period.
Also, just for the heck of it, I slapped on the 18-55mm kit lens that came with the camera, and didn't have any problems.
It's just with those long telefocus lengths, at least with the 55-250mm lens that I have.
Is this normal?
Steve Thomas
