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20mm F1.7 AF in video
  • Hello, i just got my 20mm today. I noticed that continuous focus is fast and accurate before i start recording. Once i hit the record button, the AF tends to be slow and could not focus a certain area. but once the recording is stopped, the OOF area quickly gets focused. Is this a setting problem or what not? Or its a known problem on the 20mm. Or is this a faulty lens ( i got it as a used item. ) Thanks in advance! (:
  • 16 Replies sorted by
  • As far as I know, the 20mm has only AFS - no AFC during recording. Actually you should see a message telling you to put the dial in AFS mode... Maybe you are just ignoring it :)
  • Yup I put it in AFS. the continuous focus before recording is the pre-af. The pre af is fast but noisy. Once record button is being pressed, the continuous AF tends to b slow but the af motor is silent this time! I personally dont mind the noisy af motor. I just need to focus to be quick like the pre-af focus. (:
  • Prior to Official GH1 v1.2 Firmware, the 20mm lens focus was Noisier AND Faster... so I hear, I've not used my GH1 with v1.1, but might give it a try if v1.1 can be had.

    Perhaps an option to use older firmware focus speeds on the 20mm can be found
    Maybe they just added some loops or divisors in the code to slow down the focus works (just wishful dreaming)

    Vitaliy, is something like this possible?
  • I don’t have a GH1. However, the 20mm F1.7 will AFC(Continuously auto Focus) in video mode for both the GF1 and the GH2. It will not AFC for stills in burst mode which is why it tells you to switch to AFS. If you don’t switch it will still only operate in AFS mode for stills.

    It will AFC in pre-focus though. However, it is always slow and sometimes noisy. Hopefully, the 25mm F1.4 will have none of these issues.

    Here is a sample of the 20mm F1.7 doing AFC during video with the GH2.


  • "Angry Bird!!!"

    PL 25 is not video optimized. It does hunt at 1.4.
  • Stonebat, do you have the 25mm F1.4 or have you used it already? I was hoping it would AF as well as the 14mm F2.5. If not then I will have to cancel my pre-orders and probably buy into Oly and their new AF system.
  • I saw a sample video last week. In low contrast area, it did hunt quite a bit at 1.4. Yes it passed the focus point, got blurred, then refocused again... just like 20.7 pancake. It seems it's not video optimized.

    I canceled my preorder.

    Let's just wait and see. No need to hurry.
  • @stonebat
    Perfect chance to keep 20mm and buy 35mm F1.4 Rokinon.
  • What is it that you don't like about the 30mm F1.4? It is definitely soft wide open. However, not more so than the other fast lenses.
  • >It is definitely soft wide open. However, not more so than the other fast lenses.

    You mean Sigma 30mm? I don't know, I latked to few you have this lens, and they like it, but mostly not wide open.
    My Rokinon copy is sharp from F1.4.
  • Do you have any samples with the Rokinon? That does look like a good lens for the price.
  • >Do you have any samples with the Rokinon? That does look like a good lens for the price.

    All I have are personal photos and few tests. I got it very short time ago.
    I'll try to make something suitable for sharing as soon as free time will allow me.
  • Yeap I'm keeping 20.7. Soon I will get Lumix 14-45. I considered 14/2.5 but some said it's soft at 2.5.

    Rokinon 35.4 + Pentax K adapter around $530. Hmmm... I will wait for m.zuiko 45.8 review.
  • @Vitaliy

    Don't rush. I am sure everyone would rather see the hack instead of the samples.
  • the look on his face at 0:17 is priceless!
  • The major resellers have run out of 20mm 1.7 for weeks...