BrunoCH

I have the same problem with my nikkor zoom 25-50. Back focus need to be very precise and it can move just with a change in temperature. This is why there is a back focus adjustment ring on the zoom fujinon MK.
This Ebay seller
https://www.ebay.fr/usr/ramir73?_trksid=p2047675.l2559
sells M42 adapter to Fuji X with a back focus adjustment. I have exchanged messages with him and he will see if he can do something for a Nikon to Fuji X adapter. I’m waiting !

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.
 

Very good idea. It was with Nikon AI or AIS lenses on my Canon 550D (T2i) that I started shooting my short films in 2011. You get beautiful pictures.
Here is a site to identify all the nikon lenses that exist.
http://www.photosynthesis.co.nz/nikon/lenses.html

Thank you all for your support. I have decided to go with trying out one Nikon lens and as an added note I already have a back-up lens, which is my 28-70 F/2.8.

That's it. Start with one standard lens. 35mm for an APSC sensor or 50mm for a Full frame sensor.

Pick two or three of those focal lengths and buy quality lenses instead of trying to buy 9 cheap and poor quality ones.
Then go film something.
Even better yet, buy one really nice lens, then go film things and never look back and never take it off your camera.

Faster yes...  lots of people make similar comments about films in this vein too!

Reckon there are toddles who could bash out a similar painting faster

Oh, I don't know...  I think it depends on the operator: https://lithub.com/the-painting-that-took-22-years-to-finish/ 

Unless you include a Foveon camera on a slightly overcast day.

I love that the BTS is a painting.
Oil on canvas has the longest exposure time of any visual medium available I think..

https://commons.wikimedia.org/wiki/File:Une_noce_chez_le_photographe.jpg
https://www.ader-paris.fr/lot/19598/3860018?npp=20&
 

https://commons.wikimedia.org/wiki/File:Une_noce_chez_le_photographe.jpg
https://www.ader-paris.fr/lot/19598/3860018?npp=20&
 

https://commons.wikimedia.org/wiki/File:Une_noce_chez_le_photographe.jpg
https://www.ader-paris.fr/lot/19598/3860018?npp=20&
 

Sometimes you have to properly shim the lens to get the parfocal ability.

Honestly was pretty impressed by your tests, yes it's not razor sharp but it has a nice clean look and it's lack of contrast can be a good thing.

When looking for a zoom for my XT3, I discovered the existence of a 25-50mm nikkor AI. Originally, it was a wide zoom for 24x36mm which went from the standard focal to a wide angle. On the XT3’ sensor, it is a zoom very well centered on the standard focal, a bit like an 18-55 but with a narrower range.
I found a copy in very good condition on Ebay for 105 $ + 24 $ shipping.
I received it yesterday morning and I did a few quick tests in the afternoon.
 
Pros :
Optical quality and build contruction
Price
All manual with 3 rings: aperture, zoom, focus.
 
Cons :
Maximum aperture at F4 (too soft, it must be opened at 5.6 at least to have the full quality of this lens)
Not Parfocal. The focus moves when you change the focal length.
 
I chose the AI version because focus throw AI version 130° vs 75° AIS version.
 
If you want to view some boring  crapy shots.
password: nikkor2550
https://vimeo.com/397291419?activityReferer=1

I've often wondered about this lens, so I was happy to see your post. Your samples look great. Were you focusing as you were zooming because it looked like it held focus pretty well? Did you shoot this with one of the Fuji's film simulations, or did you grade this? Either way, the color looks nice!

When looking for a zoom for my XT3, I discovered the existence of a 25-50mm nikkor AI. Originally, it was a wide zoom for 24x36mm which went from the standard focal to a wide angle. On the XT3’ sensor, it is a zoom very well centered on the standard focal, a bit like an 18-55 but with a narrower range.
I found a copy in very good condition on Ebay for 105 $ + 24 $ shipping.
I received it yesterday morning and I did a few quick tests in the afternoon.
 
Pros :
Optical quality and build contruction
Price
All manual with 3 rings: aperture, zoom, focus.
 
Cons :
Maximum aperture at F4 (too soft, it must be opened at 5.6 at least to have the full quality of this lens)
Not Parfocal. The focus moves when you change the focal length.
 
I chose the AI version because focus throw AI version 130° vs 75° AIS version.
 
If you want to view some boring  crapy shots.
password: nikkor2550
https://vimeo.com/397291419?activityReferer=1

No hope on the side of old lenses all designed for the 24x36mm. Maybe a company like Meike (when I see the quality of their cine lenses) could release a cine zoom
18-55 mm
T 2.9 constant
parfocal
10 blades iris
a focus throw > 200 degrees
APS-C (mounts : M4 / 3, FujiX, SonyE)
Around 1500 dollars.
Or Sirui by an indigogo campaign.
Maybe we could suggest them. An email isn’t expensive. A daydream isn’t expensive too.

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.

This two Meike cine lenses are fine. Manual focus is very precise with a 270 ° focus throw and with a very smooth  feeling.
https://meikeglobal.com/collections/meike-cine-lens/products/presale-meike-t2-2-cine-lens-for-fujifilm-x-mount-mk-35mm-t2-2-with-aps-c
https://meikeglobal.com/collections/meike-cine-lens/products/meike-25mm-t2-2-large-aperture-manual-focus-prime-low-distortion-mini-cine-lens-compatible-with-fujifilm-x-mount-cameras-x-h1-x-t3-x-t20-x-t10-x-t2-x-pro2-x-e3-x-t1-x-a2-t100-x-e1-x30-x70-x-m1-x-a1

First shot with my new Meike cine lenses (25 and 35mm). It's just a sequence for an actress demo reel. Really satisfied with these new lenses.
Pros :
- great color rendition and contrast.
- almost no focus breathing.
- long focus throw
- the aperture ring is not linear (exposure adjustment is much easier and precise)
- build all metal
- price
 
Cons :
- 25mm is the widest focal length for X mount. (12 and 16mm cover only MFT sensor)
- 50mm and 65mm will be released later, but doesn’t yet exist in X mount.
- very sensitive to side flare.
 
The wide shot with the 25mm
Close shots with the 35 mm + black promist 1/4 filter
2000 ISO

First shot with my new Meike cine lenses (25 and 35mm). It's just a sequence for an actress demo reel. Really satisfied with these new lenses.
Pros :
- great color rendition and contrast.
- almost no focus breathing.
- long focus throw
- the aperture ring is not linear (exposure adjustment is much easier and precise)
- build all metal
- price
 
Cons :
- 25mm is the widest focal length for X mount. (12 and 16mm cover only MFT sensor)
- 50mm and 65mm will be released later, but doesn’t yet exist in X mount.
- very sensitive to side flare.
 
The wide shot with the 25mm
Close shots with the 35 mm + black promist 1/4 filter
2000 ISO

I have used the 1.18 crop to advantage with a C mount adapter, for 2K.
Using a Vario-Switar zoom 18-86 f2.5 from a Bolex 16mm camera, you can shoot 4K60p and edit in a 1080 60p timeline in Final Cut Pro
well within the image circle (set "Spacial Conform" to NONE). I usually reduce the scale to about 0.84 before is see vignetting, to get the widest view.
This is a H16 RX lens, but I find no focus problems from the RX adjustment for the Bolex viewfinder prism. Its very sharp at mid apertures throughout the
nearly 5:1 zoom range. The version of this lens I have is one of the early ones without the electric eye & automatic aperture so it has a smaller projection
coming off the side with the Bolex trigger, so it is not a problem mounting this on the X-T3.

Write it up in your native language and we can put it through google translate?  Language isn't the barrier it used to be and shouldn't get in the way of talking about what matters.