Jay60p

My 2018 Mac mini has the T2 chip.
In the Handbrake compressor video encoder there are two Apple “VideoToolbox” modes,
one H264 & one H265.
These modes have accelerated encoding several times faster
than the other modes, and I think these use the T2 chip for encoding.

Unfortunately my "H.265 (VideoToolbox)" encoding test from 10bit input came out 8bit from Handbrake.
Nevertheless Quicktime playback of 4k60p 10bit HEVC is always smooth on this machine.
 

23 year old Nixon was the OG camera nerd.  Probably shooting 25 fps PAL footage. 

Isn't that Richard Nixon on that Ikonoskop Kamera?

https://telefunken.com/
the microphones are some of the best ever build https://www.telefunken-elektroakustik.com/
 

The good news is that these DIY methods are easy, I'm set now and don't need to try the Pro adapters.
If the adapters were too long instead of short, then we'd really be screwed!
Here's my final results with my 35mm SLR zoom lenses & adapters I use for video (your results may differ)...
Nikkor AF 28-85mm f/3.5-4.5 on Fotodiox NIK-FX - parfocal, no adjustment needed.
Nikkor AF 28-85mm f/3.5-4.5 on Fotodiox NIK(G)-FX - needs extension for parfocality.
Canon FD 35-70 f4, and Canon FD 70-210 f4 on Fotasy FD-FX - parfocal, no adjustment needed.
SMC Pentax-AF 100-300 f/4.5-5.6 on Fotodiox PK(A)-FX - needs extension for parfocality.
 

P.S.   If my X-T3 shots don't look so hot, they were blow-ups from the full frame's view:

and shot in available light in UHD at 60p but only 100mb/s, at ISO 10,000 since it was a quick and dirty lens test.
Didn't know I'd be putting this online.

Here is a Nikkor AF 28-85mm f/3.5-4.5 SLR zoom lens mounted on my X-T3,
with the basic Fotodiox adapter for Nikon F.
The lens focus is parfocal from 28mm to 85mm, with a smooth zoom ring, great for video zooms:

 
So I was surprised to find weeks later that it suddenly was not
holding its focus, it was focusing farther at wide angle (??)
At 85mm, focused manually (a screen grab cropped into the video):

 
Then zoomed out to 28mm, the focus shifted behind the subject:

 
Eventually I realized that I was using a different Fotodiox Nikon F adapter this time,
and the only difference was an aperture control ring built in for G lenses:

 
I compared the thickness of the two adapters with a small C clamp.
The G adapter was a hair shorter than the basic adapter,
and the G adapter had the lens focus going too far past infinity.
So I decided to extend the G adapter’s length a slight bit.
I removed the back of the adapter by removing four screws,
and I added a thin layer of tape to extend the adapter’s overall length:

Finding the right thickness of tape was trial and error.
Thin cardboard, too thick. Duct tape, too thick. Black masking tape worked.
Now after zooming out it is back in focus:

 
So a mounting error of the thickness of masking tape threw off the zoom’s parfocality!
How thick was this tape? I have an old caliper from my grandfather, and it measures
in 1/1,000 inch increments. (But not wide enough to measure the Nikon adapters):

The masking tape is seven thousandths of an inch thick. That's about a sixth of a millimeter.
The moral of the story: if your vintage zoom lens adapted to your mirrorless camera
appears not parfocal for video, try another brand of adapter, especially if it has infinity focus
adjustments. Apparently all it takes is a few thousandths of an inch to throw it off.
 

Here is a Nikkor AF 28-85mm f/3.5-4.5 SLR zoom lens mounted on my X-T3,
with the basic Fotodiox adapter for Nikon F.
The lens focus is parfocal from 28mm to 85mm, with a smooth zoom ring, great for video zooms:

 
So I was surprised to find weeks later that it suddenly was not
holding its focus, it was focusing farther at wide angle (??)
At 85mm, focused manually (a screen grab cropped into the video):

 
Then zoomed out to 28mm, the focus shifted behind the subject:

 
Eventually I realized that I was using a different Fotodiox Nikon F adapter this time,
and the only difference was an aperture control ring built in for G lenses:

 
I compared the thickness of the two adapters with a small C clamp.
The G adapter was a hair shorter than the basic adapter,
and the G adapter had the lens focus going too far past infinity.
So I decided to extend the G adapter’s length a slight bit.
I removed the back of the adapter by removing four screws,
and I added a thin layer of tape to extend the adapter’s overall length:

Finding the right thickness of tape was trial and error.
Thin cardboard, too thick. Duct tape, too thick. Black masking tape worked.
Now after zooming out it is back in focus:

 
So a mounting error of the thickness of masking tape threw off the zoom’s parfocality!
How thick was this tape? I have an old caliper from my grandfather, and it measures
in 1/1,000 inch increments. (But not wide enough to measure the Nikon adapters):

The masking tape is seven thousandths of an inch thick. That's about a sixth of a millimeter.
The moral of the story: if your vintage zoom lens adapted to your mirrorless camera
appears not parfocal for video, try another brand of adapter, especially if it has infinity focus
adjustments. Apparently all it takes is a few thousandths of an inch to throw it off.
 

Here is a Nikkor AF 28-85mm f/3.5-4.5 SLR zoom lens mounted on my X-T3,
with the basic Fotodiox adapter for Nikon F.
The lens focus is parfocal from 28mm to 85mm, with a smooth zoom ring, great for video zooms:

 
So I was surprised to find weeks later that it suddenly was not
holding its focus, it was focusing farther at wide angle (??)
At 85mm, focused manually (a screen grab cropped into the video):

 
Then zoomed out to 28mm, the focus shifted behind the subject:

 
Eventually I realized that I was using a different Fotodiox Nikon F adapter this time,
and the only difference was an aperture control ring built in for G lenses:

 
I compared the thickness of the two adapters with a small C clamp.
The G adapter was a hair shorter than the basic adapter,
and the G adapter had the lens focus going too far past infinity.
So I decided to extend the G adapter’s length a slight bit.
I removed the back of the adapter by removing four screws,
and I added a thin layer of tape to extend the adapter’s overall length:

Finding the right thickness of tape was trial and error.
Thin cardboard, too thick. Duct tape, too thick. Black masking tape worked.
Now after zooming out it is back in focus:

 
So a mounting error of the thickness of masking tape threw off the zoom’s parfocality!
How thick was this tape? I have an old caliper from my grandfather, and it measures
in 1/1,000 inch increments. (But not wide enough to measure the Nikon adapters):

The masking tape is seven thousandths of an inch thick. That's about a sixth of a millimeter.
The moral of the story: if your vintage zoom lens adapted to your mirrorless camera
appears not parfocal for video, try another brand of adapter, especially if it has infinity focus
adjustments. Apparently all it takes is a few thousandths of an inch to throw it off.
 

Here is a Nikkor AF 28-85mm f/3.5-4.5 SLR zoom lens mounted on my X-T3,
with the basic Fotodiox adapter for Nikon F.
The lens focus is parfocal from 28mm to 85mm, with a smooth zoom ring, great for video zooms:

 
So I was surprised to find weeks later that it suddenly was not
holding its focus, it was focusing farther at wide angle (??)
At 85mm, focused manually (a screen grab cropped into the video):

 
Then zoomed out to 28mm, the focus shifted behind the subject:

 
Eventually I realized that I was using a different Fotodiox Nikon F adapter this time,
and the only difference was an aperture control ring built in for G lenses:

 
I compared the thickness of the two adapters with a small C clamp.
The G adapter was a hair shorter than the basic adapter,
and the G adapter had the lens focus going too far past infinity.
So I decided to extend the G adapter’s length a slight bit.
I removed the back of the adapter by removing four screws,
and I added a thin layer of tape to extend the adapter’s overall length:

Finding the right thickness of tape was trial and error.
Thin cardboard, too thick. Duct tape, too thick. Black masking tape worked.
Now after zooming out it is back in focus:

 
So a mounting error of the thickness of masking tape threw off the zoom’s parfocality!
How thick was this tape? I have an old caliper from my grandfather, and it measures
in 1/1,000 inch increments. (But not wide enough to measure the Nikon adapters):

The masking tape is seven thousandths of an inch thick. That's about a sixth of a millimeter.
The moral of the story: if your vintage zoom lens adapted to your mirrorless camera
appears not parfocal for video, try another brand of adapter, especially if it has infinity focus
adjustments. Apparently all it takes is a few thousandths of an inch to throw it off.
 

Here is a Nikkor AF 28-85mm f/3.5-4.5 SLR zoom lens mounted on my X-T3,
with the basic Fotodiox adapter for Nikon F.
The lens focus is parfocal from 28mm to 85mm, with a smooth zoom ring, great for video zooms:

 
So I was surprised to find weeks later that it suddenly was not
holding its focus, it was focusing farther at wide angle (??)
At 85mm, focused manually (a screen grab cropped into the video):

 
Then zoomed out to 28mm, the focus shifted behind the subject:

 
Eventually I realized that I was using a different Fotodiox Nikon F adapter this time,
and the only difference was an aperture control ring built in for G lenses:

 
I compared the thickness of the two adapters with a small C clamp.
The G adapter was a hair shorter than the basic adapter,
and the G adapter had the lens focus going too far past infinity.
So I decided to extend the G adapter’s length a slight bit.
I removed the back of the adapter by removing four screws,
and I added a thin layer of tape to extend the adapter’s overall length:

Finding the right thickness of tape was trial and error.
Thin cardboard, too thick. Duct tape, too thick. Black masking tape worked.
Now after zooming out it is back in focus:

 
So a mounting error of the thickness of masking tape threw off the zoom’s parfocality!
How thick was this tape? I have an old caliper from my grandfather, and it measures
in 1/1,000 inch increments. (But not wide enough to measure the Nikon adapters):

The masking tape is seven thousandths of an inch thick. That's about a sixth of a millimeter.
The moral of the story: if your vintage zoom lens adapted to your mirrorless camera
appears not parfocal for video, try another brand of adapter, especially if it has infinity focus
adjustments. Apparently all it takes is a few thousandths of an inch to throw it off.
 

Hello from the USA!
Current camera Fuji X-T3, with my latest lens
acquisition AF-n Nikkor 28-85mm f/3.5-4.5,
And DIY lens support rails built with old chem lab hardware.

I’m married with two boys in high school, retired.
Favorite music: classical (Bach & Beethoven),
and British ’70’s rock (Yes, ELP, Who, Tull, etc)
Hobbies: playing an old grand piano, Hammond M3, Minimoog, Prophet,
Rhodes 73, Peavey DPM-C8.
Recording Multi-track (used to be Tascam 38, now Macintosh).
Lionel train layout & miniature village,
Old movie film production equipment & projectors in 16 & 35mm,
Tinkering with various hardware & old equipment parts to do something new.
EOSHD coverage: looking forward to new tips & tricks for mirrorless video,
best vintage lenses, and comparisons of the new cameras.
I found EOSHD early 2019 after getting the Fuji X-T3.
My 1st DSLR was Fuji S1 Pro (great color! https://***URL removed***/reviews/fujis1pro,
pictured with the same Nikon lens I used.) Next was the Canon T2i.
But I did not use these for video and never looked at photography forums online.
But Fuji X-T3 is a completely different animal!

Hello from the USA!
Current camera Fuji X-T3, with my latest lens
acquisition AF-n Nikkor 28-85mm f/3.5-4.5,
And DIY lens support rails built with old chem lab hardware.

I’m married with two boys in high school, retired.
Favorite music: classical (Bach & Beethoven),
and British ’70’s rock (Yes, ELP, Who, Tull, etc)
Hobbies: playing an old grand piano, Hammond M3, Minimoog, Prophet,
Rhodes 73, Peavey DPM-C8.
Recording Multi-track (used to be Tascam 38, now Macintosh).
Lionel train layout & miniature village,
Old movie film production equipment & projectors in 16 & 35mm,
Tinkering with various hardware & old equipment parts to do something new.
EOSHD coverage: looking forward to new tips & tricks for mirrorless video,
best vintage lenses, and comparisons of the new cameras.
I found EOSHD early 2019 after getting the Fuji X-T3.
My 1st DSLR was Fuji S1 Pro (great color! https://***URL removed***/reviews/fujis1pro,
pictured with the same Nikon lens I used.) Next was the Canon T2i.
But I did not use these for video and never looked at photography forums online.
But Fuji X-T3 is a completely different animal!

Hello from the USA!
Current camera Fuji X-T3, with my latest lens
acquisition AF-n Nikkor 28-85mm f/3.5-4.5,
And DIY lens support rails built with old chem lab hardware.

I’m married with two boys in high school, retired.
Favorite music: classical (Bach & Beethoven),
and British ’70’s rock (Yes, ELP, Who, Tull, etc)
Hobbies: playing an old grand piano, Hammond M3, Minimoog, Prophet,
Rhodes 73, Peavey DPM-C8.
Recording Multi-track (used to be Tascam 38, now Macintosh).
Lionel train layout & miniature village,
Old movie film production equipment & projectors in 16 & 35mm,
Tinkering with various hardware & old equipment parts to do something new.
EOSHD coverage: looking forward to new tips & tricks for mirrorless video,
best vintage lenses, and comparisons of the new cameras.
I found EOSHD early 2019 after getting the Fuji X-T3.
My 1st DSLR was Fuji S1 Pro (great color! https://***URL removed***/reviews/fujis1pro,
pictured with the same Nikon lens I used.) Next was the Canon T2i.
But I did not use these for video and never looked at photography forums online.
But Fuji X-T3 is a completely different animal!

Hello from the USA!
Current camera Fuji X-T3, with my latest lens
acquisition AF-n Nikkor 28-85mm f/3.5-4.5,
And DIY lens support rails built with old chem lab hardware.

I’m married with two boys in high school, retired.
Favorite music: classical (Bach & Beethoven),
and British ’70’s rock (Yes, ELP, Who, Tull, etc)
Hobbies: playing an old grand piano, Hammond M3, Minimoog, Prophet,
Rhodes 73, Peavey DPM-C8.
Recording Multi-track (used to be Tascam 38, now Macintosh).
Lionel train layout & miniature village,
Old movie film production equipment & projectors in 16 & 35mm,
Tinkering with various hardware & old equipment parts to do something new.
EOSHD coverage: looking forward to new tips & tricks for mirrorless video,
best vintage lenses, and comparisons of the new cameras.
I found EOSHD early 2019 after getting the Fuji X-T3.
My 1st DSLR was Fuji S1 Pro (great color! https://***URL removed***/reviews/fujis1pro,
pictured with the same Nikon lens I used.) Next was the Canon T2i.
But I did not use these for video and never looked at photography forums online.
But Fuji X-T3 is a completely different animal!

Hello from the USA!
Current camera Fuji X-T3, with my latest lens
acquisition AF-n Nikkor 28-85mm f/3.5-4.5,
And DIY lens support rails built with old chem lab hardware.

I’m married with two boys in high school, retired.
Favorite music: classical (Bach & Beethoven),
and British ’70’s rock (Yes, ELP, Who, Tull, etc)
Hobbies: playing an old grand piano, Hammond M3, Minimoog, Prophet,
Rhodes 73, Peavey DPM-C8.
Recording Multi-track (used to be Tascam 38, now Macintosh).
Lionel train layout & miniature village,
Old movie film production equipment & projectors in 16 & 35mm,
Tinkering with various hardware & old equipment parts to do something new.
EOSHD coverage: looking forward to new tips & tricks for mirrorless video,
best vintage lenses, and comparisons of the new cameras.
I found EOSHD early 2019 after getting the Fuji X-T3.
My 1st DSLR was Fuji S1 Pro (great color! https://***URL removed***/reviews/fujis1pro,
pictured with the same Nikon lens I used.) Next was the Canon T2i.
But I did not use these for video and never looked at photography forums online.
But Fuji X-T3 is a completely different animal!

Hello from the USA!
Current camera Fuji X-T3, with my latest lens
acquisition AF-n Nikkor 28-85mm f/3.5-4.5,
And DIY lens support rails built with old chem lab hardware.

I’m married with two boys in high school, retired.
Favorite music: classical (Bach & Beethoven),
and British ’70’s rock (Yes, ELP, Who, Tull, etc)
Hobbies: playing an old grand piano, Hammond M3, Minimoog, Prophet,
Rhodes 73, Peavey DPM-C8.
Recording Multi-track (used to be Tascam 38, now Macintosh).
Lionel train layout & miniature village,
Old movie film production equipment & projectors in 16 & 35mm,
Tinkering with various hardware & old equipment parts to do something new.
EOSHD coverage: looking forward to new tips & tricks for mirrorless video,
best vintage lenses, and comparisons of the new cameras.
I found EOSHD early 2019 after getting the Fuji X-T3.
My 1st DSLR was Fuji S1 Pro (great color! https://***URL removed***/reviews/fujis1pro,
pictured with the same Nikon lens I used.) Next was the Canon T2i.
But I did not use these for video and never looked at photography forums online.
But Fuji X-T3 is a completely different animal!

Hello from the USA!
Current camera Fuji X-T3, with my latest lens
acquisition AF-n Nikkor 28-85mm f/3.5-4.5,
And DIY lens support rails built with old chem lab hardware.

I’m married with two boys in high school, retired.
Favorite music: classical (Bach & Beethoven),
and British ’70’s rock (Yes, ELP, Who, Tull, etc)
Hobbies: playing an old grand piano, Hammond M3, Minimoog, Prophet,
Rhodes 73, Peavey DPM-C8.
Recording Multi-track (used to be Tascam 38, now Macintosh).
Lionel train layout & miniature village,
Old movie film production equipment & projectors in 16 & 35mm,
Tinkering with various hardware & old equipment parts to do something new.
EOSHD coverage: looking forward to new tips & tricks for mirrorless video,
best vintage lenses, and comparisons of the new cameras.
I found EOSHD early 2019 after getting the Fuji X-T3.
My 1st DSLR was Fuji S1 Pro (great color! https://***URL removed***/reviews/fujis1pro,
pictured with the same Nikon lens I used.) Next was the Canon T2i.
But I did not use these for video and never looked at photography forums online.
But Fuji X-T3 is a completely different animal!

Hello from the USA!
Current camera Fuji X-T3, with my latest lens
acquisition AF-n Nikkor 28-85mm f/3.5-4.5,
And DIY lens support rails built with old chem lab hardware.

I’m married with two boys in high school, retired.
Favorite music: classical (Bach & Beethoven),
and British ’70’s rock (Yes, ELP, Who, Tull, etc)
Hobbies: playing an old grand piano, Hammond M3, Minimoog, Prophet,
Rhodes 73, Peavey DPM-C8.
Recording Multi-track (used to be Tascam 38, now Macintosh).
Lionel train layout & miniature village,
Old movie film production equipment & projectors in 16 & 35mm,
Tinkering with various hardware & old equipment parts to do something new.
EOSHD coverage: looking forward to new tips & tricks for mirrorless video,
best vintage lenses, and comparisons of the new cameras.
I found EOSHD early 2019 after getting the Fuji X-T3.
My 1st DSLR was Fuji S1 Pro (great color! https://***URL removed***/reviews/fujis1pro,
pictured with the same Nikon lens I used.) Next was the Canon T2i.
But I did not use these for video and never looked at photography forums online.
But Fuji X-T3 is a completely different animal!

Hello from the USA!
Current camera Fuji X-T3, with my latest lens
acquisition AF-n Nikkor 28-85mm f/3.5-4.5,
And DIY lens support rails built with old chem lab hardware.

I’m married with two boys in high school, retired.
Favorite music: classical (Bach & Beethoven),
and British ’70’s rock (Yes, ELP, Who, Tull, etc)
Hobbies: playing an old grand piano, Hammond M3, Minimoog, Prophet,
Rhodes 73, Peavey DPM-C8.
Recording Multi-track (used to be Tascam 38, now Macintosh).
Lionel train layout & miniature village,
Old movie film production equipment & projectors in 16 & 35mm,
Tinkering with various hardware & old equipment parts to do something new.
EOSHD coverage: looking forward to new tips & tricks for mirrorless video,
best vintage lenses, and comparisons of the new cameras.
I found EOSHD early 2019 after getting the Fuji X-T3.
My 1st DSLR was Fuji S1 Pro (great color! https://***URL removed***/reviews/fujis1pro,
pictured with the same Nikon lens I used.) Next was the Canon T2i.
But I did not use these for video and never looked at photography forums online.
But Fuji X-T3 is a completely different animal!

A few video experiments to try at home:
Slow motion and reverse motion:
Water drops
Remote control toys (RC cars, helicopters, etc)
Collapsing constructions of blocks, toys, dominoes, etc…
Put on a gorilla suit and hit a pile of bones with a large femur.
Stop motion animation:
Clay (Gumby, Wallace & Gromit).
Toy figures with armatures.
https://www.youtube.com/watch?v=Gg1KCyU1JEU
Lego blocks building themselves.
Drawing on paper (animate the progress of a piece of flat art)
Moving sand/small bits of stuff in patterns.
https://www.youtube.com/watch?v=578Xm6bgMdQ
Best to use a tripod, or a copy stand (I use an old enlarger stand),
unchanging light source, and a remote control to avoid touching
the camera.
Timelapse, (cameras with interval recording)
Such as, watch a window’s sunlight move across a room,
ice cubes melting, traffic at intersections.
I use vintage SLR lenses for stop motion & timelapse
since the apertures and focus
cannot be inadvertently changed by the camera.
To get the classic slow shutter blur for fast moving objects
I put two polarizers on the lens and rotate one to darken the
image to the point where I can use one second exposures.
Variable neutral density filters should do the same thing.
(Fuji owners: 1)My Fuji camera kit lens will stop down at each frame
and then open up again until the next frame. There is a small
difference in the actual aperture that is set each time which can
result in a small amount of flicker. Manual lenses with adapters
avoid this.
2) One thing that can make my X-T3 skip a frame is setting the
viewfinder to come on only when you put your eye to it.
I thought I could save battery power by having LCD & EVF off until
I put my eye to the viewfinder, but I found frames were being skipped
about as often as I looked through the EVF, so I think making the
EVF turn on can interrupt the interval recording.)
 

Excellent. Thank you.

For the low budget videographers among us: a ZOOM LENS report.
On the X-T3 the Fuji zooms have problems with video shooting, including exposure stepping
and focus-by-wire jumpyness that is not a problem with stills.
So I thought I'd report on a recent Nikon zoom I found to work around these issues.
 
The Nikkor AF 28-85 f3.5-4.5 (1986-1999) is a great manual zoom/manual aperture ring
lens to use on the X-T3. It is extremely affordable, I picked up a clean one in a local camera
shop for $50, and mounted it with the $20 fotodiox adapter. It is a full frame SLR lens.
 
It is PARFOCAL, the focus does not stray as you zoom in & out.
I found the change in brightness as you zoom to be often unnoticeable unless you are watching
for it, this really surprised me. f3.5 to 4.5 is less than a stop of change, about 2/3rds of a stop?
 
And most important, the zoom ring is smooth. Often these Nikon zooms are slightly sticky,
especially when trying to turn the zoom ring very slowly for a cinematic shot.
The focus ring has a good amount of smooth travel for easy manual focus.
 
Finally, the sharpness of this lens is excellent, compares to the 18-55 fuji kit lens.
With some pixel peeping I can see a little CA color fringing at the edges, which you
would expect for a vintage lens without in-camera digital corrections.
There is a glowing review of this lens by Ken Rockwell online.
 
I have another Nikon zoom which is not usable (24-85mm F2.8-4) from 2001,
due to a sticky zoom ring, plus a manual focus ring which has a very short travel and is
difficult for fine focusing at distances nearing infinity.
Some zooms may have become sticky over years of continous use,
keep in mind when looking in ebay etc.
 
Vintage SLR zooms are often very parfocal, I also have two Canon FD zooms that
hold focus as well, 35-70 f4 and 70-210 f4. I used the 35-70 for 30 years on my SLR
and the zoom ring is still smooth.
 
So for $70 you can get an excellent Nikkor 3:1 full frame zoom, especially if you don't have
$3000-4000 for an excellent Fujinon 3:1 Cinema zoom.
I am posting here rather than in the LENS forum because the Sony & Panasonic camera zooms
may not have the same issues as Fuji.

Auto Focus. All the youtubers are consumed with auto focus performance. Every review is praising or dissing AF
for every new camera. Everyone has videos of people jumping in & out of frame and watching the focus change to this & that. Is it tracking?? Is it twitchy, is it slow, is it focusing on the wrong subject etc etc. and the stupid AI algorithms are driving us camera owners crazy if it doesn't quite perform right. The first few months I had a new mirrorless I would end up watching every shot for signs of AF error, I become sensitized to every background twitch & focus shift, I was alternately disappointed or elated depending on the AutoFocus results.

Finally during a brief period of sanity I turned off the AF and went totally manual focus. I planned what my shots were going to do AHEAD OF TIME and set the focus WITH THE FOCUS RING! I stopped watching the shots for AF and could pay attention to everything else.  No more focus wobbles, jumps, twitches & tracking errors, just … calm.  Then I had a shot where two people were talking and one suddenly walked past the camera left while still talking. I followed him a ways and then panned back. Hey, he went out of focus! The other person said a few words and the shot ended. Later I watched this shot and sure enough he moved out of focus. But, it didn’t bother me. I realized if the focus had tried to follow him and then jump back to the other person it would have been quite distracting to me, but having a subject naturally move out of focus as he moved through the scene made me realize that happens in the movies all the time and no-one cares.  
So relax, turn off that AF.  Let the background trees stay out of focus when Camera Conspiracies jumps out of the shot. Manual Focus rules.

Auto Focus. All the youtubers are consumed with auto focus performance. Every review is praising or dissing AF
for every new camera. Everyone has videos of people jumping in & out of frame and watching the focus change to this & that. Is it tracking?? Is it twitchy, is it slow, is it focusing on the wrong subject etc etc. and the stupid AI algorithms are driving us camera owners crazy if it doesn't quite perform right. The first few months I had a new mirrorless I would end up watching every shot for signs of AF error, I become sensitized to every background twitch & focus shift, I was alternately disappointed or elated depending on the AutoFocus results.

Finally during a brief period of sanity I turned off the AF and went totally manual focus. I planned what my shots were going to do AHEAD OF TIME and set the focus WITH THE FOCUS RING! I stopped watching the shots for AF and could pay attention to everything else.  No more focus wobbles, jumps, twitches & tracking errors, just … calm.  Then I had a shot where two people were talking and one suddenly walked past the camera left while still talking. I followed him a ways and then panned back. Hey, he went out of focus! The other person said a few words and the shot ended. Later I watched this shot and sure enough he moved out of focus. But, it didn’t bother me. I realized if the focus had tried to follow him and then jump back to the other person it would have been quite distracting to me, but having a subject naturally move out of focus as he moved through the scene made me realize that happens in the movies all the time and no-one cares.  
So relax, turn off that AF.  Let the background trees stay out of focus when Camera Conspiracies jumps out of the shot. Manual Focus rules.