Fuji Lens and smooth Autofocus

[Alex Uzan]

Hi There,

I own a XT-20, and something that really bothers me when I shoot videos, is the no-smooth transition with the autofocus between 2 points, when I use the 35f2 lens.
No problem with the  16-50 f3.5-5.6

If you can't see what I'm talking About, here AF test Fuji

So I have a few questions :
1) Since it's seems to be a lens related issue, is there a list with FUJI lens that offer smooth AF transition ?
2) Do you think it could be fixed with body settings ?
 

Thanks for you help ?

 

 

[Luke Mason]

It's due to both the body and the lens, newer lenses with quad linear motors are better for smooth AF, for example the f/2.0 primes and f/2.8 zooms.

X-H1 also added customisable AF speed setting.

You could try manual focus.

[jhnkng]

I’m afraid the only Fuji with reliable, controllable, and smooth AF in video is the X-H1. It’s not quite as good as Canon’s implementation but it’s pretty darn good.  

[Alex Uzan]

On 9/5/2018 at 4:42 PM, Luke Mason said:

It's due to both the body and the lens, newer lenses with quad linear motors are better for smooth AF, for example the f/2.0 primes and f/2.8 zooms.

X-H1 also added customisable AF speed setting.

You could try manual focus.

Thanks. Unfortunately, manual focus is not an option for my kind of work.

 

On 9/6/2018 at 1:24 PM, jhnkng said:

I’m afraid the only Fuji with reliable, controllable, and smooth AF in video is the X-H1. It’s not quite as good as Canon’s implementation but it’s pretty darn good.  

I’d love to see what a xh1 could do with a 35f2 about smooth transition.

 

 

[Inazuma]

I've heard the XE3 is better than the XT20 for smooth transitions

[Thomas Hill]

1 hour ago, Inazuma said:

I've heard the XE3 is better than the XT20 for smooth transitions

I had the X-E3 for a minute and AF with the 18-55 kit lens was excellent. That's why i was so surprised by all the bad reviews of the X-H1's AF when it first came out.

[jonpais]

Excellent meaning smooth transitions like gradually pulling focus?

[Thomas Hill]

2 minutes ago, jonpais said:

Excellent meaning smooth transitions? 

Yep, all around AF excellence. Another feature it has that i really like is the button thingy to scroll through the drive settings instead of the dial under a dial brilliance. Push the button, get a list, single shot on top and movie on the bottom, one click up gets you from single to movie and one click down gets you from movie mode back to single.

But it's really not a camera for a serious video shooter...no mic jack, etc.

[Inazuma]

In fact I just remembered I actually had the XE3 for a week or two in March ? Just looked over my files now, and even with the awful 18mm f2, the autofocus and transitions are good.

[BTM_Pix]

2 hours ago, Thomas Hill said:

But it's really not a camera for a serious video shooter...no mic jack, etc.

It uses the annoying 2.5mm socket like the X-T20 so you need to use the adapter but it does have a mic input 

 

[jhnkng]

13 hours ago, Alex Uzan said:

I’d love to see what a xh1 could do with a 35f2 about smooth transition.

Ok, so here's a quick and dirty test with the X-H1 (v1.11) with the 35 f2:
https://www.dropbox.com/s/b0t4ek5w9g4pktb/XH1_35f2_VideoAF_Test.mov?dl=0

This was shot handheld wide open with IBIS on at 4k DCI using the Eterna simulation and exported as 1080p (whoops) but you kinda see all the good and the bad of the camera in these two clips. Eterna is beautiful, but the aliasing is pretty bad. It's not that hard to fix in post but the fact you need to is a bit disappointing. The first clip I selected focus using the touch screen -- you can see the AF struggling to lock onto focus and wavering on the dead cat, but it's a smooth transition through to the lens cap. I'm not super concerned because I'd manually pull focus in that kind of scenario anyway. The second clip is more the sort of thing I'd be using AF for, and I think it works far better -- as I pushed in I used the rear thumbstick to move the focus point from the left to the right, and it worked as I expected. 

Keep in mind I've had the camera for a week and I haven't really tested each different settings yet. And I do remember seeing somewhere that the 35f2 in particular has weird focusing issues. I've yet to try with any or my other lenses, I might get onto that later this week.

[Alex Uzan]

Thanks for this jhnkng
That seems better than what I can get with the X-T20.

Hopefully it will be more perfect with the X-T3/X-H2 ?

[CyclingBen]

On 9/8/2018 at 12:56 AM, jhnkng said:

Ok, so here's a quick and dirty test with the X-H1 (v1.11) with the 35 f2:
https://www.dropbox.com/s/b0t4ek5w9g4pktb/XH1_35f2_VideoAF_Test.mov?dl=0

This was shot handheld wide open with IBIS on at 4k DCI using the Eterna simulation and exported as 1080p (whoops) but you kinda see all the good and the bad of the camera in these two clips. Eterna is beautiful, but the aliasing is pretty bad. It's not that hard to fix in post but the fact you need to is a bit disappointing. The first clip I selected focus using the touch screen -- you can see the AF struggling to lock onto focus and wavering on the dead cat, but it's a smooth transition through to the lens cap. I'm not super concerned because I'd manually pull focus in that kind of scenario anyway. The second clip is more the sort of thing I'd be using AF for, and I think it works far better -- as I pushed in I used the rear thumbstick to move the focus point from the left to the right, and it worked as I expected. 

Keep in mind I've had the camera for a week and I haven't really tested each different settings yet. And I do remember seeing somewhere that the 35f2 in particular has weird focusing issues. I've yet to try with any or my other lenses, I might get onto that later this week.

Fuji needs to update the firmware on this lens, it's simply too fast for video. The 35mm is a great lens for photography and great for manual focus in video.  They just need to give the 35mm the same autofocus video code as the XF zooms.