Back button focus doesn't lock focus

[sneike]

Hi, I'm a new owner of an X-T20.

 

Since I was a bbf user on my old canon setup, I immediately disabled AF on the shutter button and I'm using the AF-ON feature on the AF-L button of the Fujifilm.

 

I'm happy with these settings and it works as I want, but the issue I found is that the focus is not locked. After pressing bbf, taking several shots will shift the focus. It happens with AF-S, single focus point or area, and on P, A or S modes.

 

I'd like to know if you have the same behaviour on your camera, I can see it happening with both the 18-55 and the 55-200. To reproduce the problem just focus on a close subject, use aperture priority wide open to narrow DOF, focus with the bbf and then start half pressing the shutter button. The camera will auto set exposure each time, and by doing this you should notice the focus moving.

 

This is a typical situation when using bbf: you focus once and then take several shots for different compositions or exposures without touching the focus.

 

In the video at this link I'm reproducing the issue. https://photos.app.goo.gl/8iWxmakf7RWGRacg1

 

You can see I focus with the bbf and I take a picture perfectly sharp. Then I activate focus check and I start half pressing the shutter button several times. The focus slightly changes each time, and at the end I take a second picture out of focus. I hope you can see the difference in video.

 

What do you think? I'm missing some setting? Does your camera behaves the same?

 

Thanks

[drandyperry]

I can't get my primes to move off focus, I'll try my kit lens when I can find it.

 

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[drandyperry]

Just had a quick go with my 18-55 kit lens and I am to be able to recreate your problem. Repeated half pressing makes the focus drift. I'll have a play with my 50-140, that's my only other zoom lens.

 

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[sneike]

Just had a quick go with my 18-55 kit lens and I am to be able to recreate your problem. Repeated half pressing makes the focus drift. I'll have a play with my 50-140, that's my only other zoom lens.

 

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Thanks for trying and reporting. Which firmware do you have on your camera? I have 1.01 on my camera, and I think it's a firmware related issue.

[drandyperry]

The close image is with my kit lens and about 5 shutter half presses . The wide shot is with one of my primes (23mm?) and it's after about 20 half presses.

Firmware is 2.10 for body.

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[drandyperry]

The close image is with my kit lens and about 5 shutter half presses . The wide shot is with one of my primes (23mm?) and it's after about 20 half presses.

Firmware is 2.10 for body. AJPX6945.JPGAJPX6942.JPG

 

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Other image!

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[sneike]

Other image! AJPX6945.JPG

 

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It means you have the issue with an X-T2?

[drandyperry]

It means you have the issue with an X-T2?

Strange it didn't happen with the primes. When I've got a bit more time I'll investigate a bit better.

 

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[Flashgj]

I have been experiencing the same issue with my X-T2 and 16-55. Very frustrating. I will test it using my primes to see if it appears to only be an issue with the zooms. I am using latest firmware on everything.

Edited July 25, 2017 by Flashgj

[Flashgj]

Possible Solution! Further testing is necessary, but I turned off “Pre Focus” in the menu settings and with my initial testing it seems to stay locked. I will need to test in the field and see if it does indeed solve the problem.

 

Those of you that are having this issue, check and see if Pre Focus is turned on, if so turn it off and let us know if you see any changes in behavior when Back Focusing.

[sneike]

Possible Solution! Further testing is necessary, but I turned off “Pre Focus” in the menu settings and with my initial testing it seems to stay locked. I will need to test in the field and see if it does indeed solve the problem.

 

Those of you that are having this issue, check and see if Pre Focus is turned on, if so turn it off and let us know if you see any changes in behavior when Back Focusing.

Unfortunately I've always had pre focus turned off.

[Flashgj]

Sneike, thanks for the response. I was really hoping that I was on to something that may help, sorry to hear that this appears not to solve the problem.

[flysurfer]

What do you think? I'm missing some setting? Does your camera behaves the same?

 

 

 

 

You'll have to wait for a firmware update, which is expected soon. In the meantime, use Shutter AF.

[dbenyakar]

Funny but I wanted to open a new thread on this exact same issue until I saw your thread.

I use X-T20 with the 18-55 kit lens, firmware 1.01 and 3.2.1 on the lens. Pre-focus is OFF.

 

I also found that I have to keep the back button pressed in order to take sharp images. Otherwise, if I use the back button to focus but then I let go of it, my images are not sharp at all. 

 

I also tried resetting the settings and setup, and no change.

 

I just sent Fuji an inquiry about this issue via this link: https://contact.fujifilm.com/cgi-bin/mail/form.cgi/japan?_ga=2.162466300.1744287699.1499059259-1910942115.1496698054

Edited August 5, 2017 by dbenyakar

[dbenyakar]

Hi, I'm a new owner of an X-T20.

 

Since I was a bbf user on my old canon setup, I immediately disabled AF on the shutter button and I'm using the AF-ON feature on the AF-L button of the Fujifilm.

 

I'm happy with these settings and it works as I want, but the issue I found is that the focus is not locked. After pressing bbf, taking several shots will shift the focus. It happens with AF-S, single focus point or area, and on P, A or S modes.

 

I'd like to know if you have the same behaviour on your camera, I can see it happening with both the 18-55 and the 55-200. To reproduce the problem just focus on a close subject, use aperture priority wide open to narrow DOF, focus with the bbf and then start half pressing the shutter button. The camera will auto set exposure each time, and by doing this you should notice the focus moving.

 

This is a typical situation when using bbf: you focus once and then take several shots for different compositions or exposures without touching the focus.

 

In the video at this link I'm reproducing the issue. https://photos.app.goo.gl/8iWxmakf7RWGRacg1

 

You can see I focus with the bbf and I take a picture perfectly sharp. Then I activate focus check and I start half pressing the shutter button several times. The focus slightly changes each time, and at the end I take a second picture out of focus. I hope you can see the difference in video.

 

What do you think? I'm missing some setting? Does your camera behaves the same?

 

Thanks

 

Have you find a solution for this issue?

[dbenyakar]

Look here specifically at fix number 2: http://www.fujifilm.com/support/digital_cameras/software/firmware/x/xt20/index.html

I hope that fixes it.