Samsung 85mm f1.4 ED lens "quivering focus" during video

[fletch murray]

I'd love to own the 85mm. I rented the lens and found it constantly adjust focus during filming video.  Anyone else having that problem?  Any solutions? Vasile, might there be a software mod to reduce the constant rechecking of focus on this lens?

[Cary Knoop]

50 minutes ago, fletch murray said:

I'd love to own the 85mm. I rented the lens and found it constantly adjust focus during filming video. 

That's not the lens that is your camera's constant auto focus.  And if you film at f/1.4 the focus hunting is going to be really bad.

For video you can use autofocus to frame the shot but constant focus is generally not a good idea.

 

[Kisaha]

..and Vasile doesn't live here anymore!

[SMGJohn]

23 hours ago, fletch murray said:

I'd love to own the 85mm. I rented the lens and found it constantly adjust focus during filming video.  Anyone else having that problem?  Any solutions? Vasile, might there be a software mod to reduce the constant rechecking of focus on this lens?

What was the lightning conditions where you filmed and what kind of ISO did you use? I find that the camera really struggles at higher ISO's with autofocus in video mode for no reasons whatsoever, in very very poor lighting conditions it struggles with focusing specially with soft textures, at 1.4 aperture I would not really recommend to use autofocus with any camera.

[fletch murray]

22 hours ago, Kisaha said:

..and Vasile doesn't live here anymore!

Hi, Kisaha,

I remember you let me know that in a recent note.  I sure would like to stay in touch with him.  Is GitHub the only place he checks?  I don't want to pester him but I did his hack that allows me to record past 29:59 min and was blown away by his expertise.  I was hoping he might have a suggestion how to "settle down" the AF on the 85mm.  It's a great lens and I wonder if it is because I had the AF set to FAST that caused the jittery searching for focus.  Neither of the other Samsung lenses I have exhibit this jittery focus search. see this dance video where the AF was buttery smooth.  (The side angle camera was the NX1. The front angle was a Canon 5D Mk3 (which looks pretty bad compared to the NX1.  This is what convinced me to buy the NX1.

 

On 12/29/2016 at 10:59 AM, Cary Knoop said:

That's not the lens that is your camera's constant auto focus.  And if you film at f/1.4 the focus hunting is going to be really bad.

For video you can use autofocus to frame the shot but constant focus is generally not a good idea.

 

So, Cary, you're recommending I not set the camera to CAF? What setting do you recommend.

CAF worked really well (granted I was on a wider lens) and  I was just so impressed how smoothly the Samsung 16-50mm's AF worked on this dance video, I thought the 85mm would be smooth too.  Maybe I should set the AF to slow instead of FAST.  (BTW the front angle on the dance video is the Canon 5D M3. The side angle and the entry shot is the NX1.  Stunningly good auto focus as I walk into the theater.  Check it out.

 

[Kisaha]

The S lenses are the best AF lenses on the NX ecosystem, the 85 is one of the slowest, especially if you go fast. Quite a big lens, too much glass inside, old design, I wouldn't expect any better. Change the AF speed (I do not own this lens, I do not know), and see how it goes.

From time to time I have to work with 5Diii's and I can't stand the image anymore.

I am joking about Vasile, he did great for the whole community, but there are people like Otto and Kino Seed that did much too (if not more) and there are still around for a word or two!

I believe Otto was the last one had some kind of communication, I can not be sure of course.