topic Re: Betreff: 20mm 1.8 autofocus jumping in Alpha & NEX interchangeable lens cameras

20mm 1.8 autofocus jumping

Amadeus2020 — Sat, 29 Aug 2020 08:07:23 GMT

Hi. I have a brand new SONY 20mm f1.8 lens. SEL20F18G, attached to an A7iii. When in continuous focus, the image on screen jumps in and out considerably as the autofocus is moving around. Is this normal? It 'zooms' in and out quite a lot as the internal mechanism moves forwards and backwards trying to find the focus. I have never seen it before on a SONY lens (I have the 55mm prime). It does not occur when the camera is in Auto, but is quite pronounced when it is in AP mode.

Betreff: 20mm 1.8 autofocus jumping

Peter_S. — Sat, 29 Aug 2020 14:21:35 GMT

Hi Amadeus,

Try to use a different aperture other than 1.8.

Guess there's too much light getting onto the focus sensor.

Cheers

Peter

Betreff: 20mm 1.8 autofocus jumping

Amadeus2020 — Sat, 29 Aug 2020 16:05:35 GMT

Hi. Thank you for replying. Actually, it is far worse at f8, 9, 10 and higher. When it's at 1.8 it's pretty stable.

Re: Betreff: 20mm 1.8 autofocus jumping

Joe_Dohn — Mon, 31 Aug 2020 15:43:06 GMT

Does this happen on the latest software version as well? I recall seeing some restrictions on this lens with the camera which recommended the latest software version (if I'm not mistaken).

Re: Betreff: 20mm 1.8 autofocus jumping

Amadeus2020 — Mon, 31 Aug 2020 17:21:46 GMT

Thank you. Software? Do you mean the firmware for the A7iii? I have googled it and found nothing. Sony has no updates that I can see pertaining to the 20mm.

Re: Betreff: 20mm 1.8 autofocus jumping

Win_88 — Thu, 03 Sep 2020 15:00:12 GMT

Hi @Amadeus2020

I found a firmware update on the Sony website for the A7III:

https://www.sony.co.uk/electronics/support/e-mount-body-ilce-7-series/ilce-7m3

Win_88

Re: Betreff: 20mm 1.8 autofocus jumping

Amadeus2020 — Thu, 03 Sep 2020 17:55:54 GMT

Thank you that's helpful. I've updated. But Sony tell me that's completely normal for this lens because of the internal mechanism (!).

Re: Betreff: 20mm 1.8 autofocus jumping

Win_88 — Fri, 04 Sep 2020 12:54:15 GMT

Hi @Amadeus2020

Having had experience with Sony support myself, If you were given that answer, it must've been the result of an investigation and the info is accurate. It must be within specifications.

Win_88