Quite normal with some lenses. You get green fringing beyond
the point of focus and magenta fringing on the camera side.

This is a Pentax_A 50mm f/1.4 wide open:




Don't go comparing lenses against the kit lens it's very good
and will see off most primes and quite a few zooms

-

Certainly did they were dancing around the top of my TV
at Midnight

Maybe they are bringing out a 10X Converter

Tommy Cooper would have advised... Don't focus on the *front* of one particular apple on a tree then!

True!!

The Green Hexagon/Beep which has been on Pentax cameras since
the MEF is the most accurate method of focusing as long as
you do the micro-AF adjustment.

Any other method of focusing you can move the camera back and
forth 6" and it still indicates in focus. The Green Hexagon/Beep
is usually +/-5mm at 900mm with an f/2.8 lens.

Catch in focus is good, but the camera is actually moving which
can cause shake.

A focusing rail preferably with a mm scale on it is essential
to get the AF/Beep adjustment right.

MF just by looking at the screen can only indicate that your
within the DOF at screen size.

It was also on the side panel

You shouldn't have a problem focussing at infinity.
You might have to send the lens back. Some lenses
are user adjustable, but not many.

That's easy to use just connect a USB lead and click DEBUG ON
on the PKTether menu. Remove from USB and switch off from the
camera when finished. I've sometimes left it for a few days in
DEBUG mode. I've one MF lens that needs -170 to work the green
light/beep when in focus. I don't think any of my lenses need
a + adjustment so I might set -100 permanently in DEBUG.

You need to set your focus to centre point only for
birds in trees or MF using the green indicator and beep.