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Pentax SDM to Screwdrive Autofocus Test

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  • เผยแพร่เมื่อ 5 ก.ย. 2021
  • Hey! In this video I tested whether the SDM or screwdrive autofocus system is faster at achieving focus confirmation from both maximum to minimum and minimum to maximum focusing distances and with the K-70 and the K-3 III.
    TL;DR: Converting to screwdrive improves focusing speed on average by 11.5%.
    How to convert your lens: • Pentax SDM to Screwdri...
    To be clear: this is only the old SDM micro-AF motors for some lenses capable of making this conversion. The new SDM ring-type designs will obviously be substantially improved.
    List of similar SDM designs:
    smc PENTAX-DA* 16-50mm f/2.8 ED AL [IF] SDM
    smc PENTAX-DA* 50-135mm f/2.8 ED [IF] SDM
    smc PENTAX DA* 60-250mm f/4 ED [IF] SDM
    smc PENTAX-DA* 200mm f/2.8 ED [IF] SDM
    smc PENTAX-DA* 300mm f/4 ED [IF] SDM
    Let me know what you think!
    Send us stuff!
    Stephen Foster
    PO Box 99900 WU 227 122
    RPO Meadowbrook
    Edmonton AB T6T 0W4

ความคิดเห็น • 16

  • @Orion795
    @Orion795 2 ปีที่แล้ว +3

    Thank you, this channel is a must

  • @sakatabg
    @sakatabg 2 ปีที่แล้ว +3

    Great test!! Great algorithm, logic and analyse!!!

  • @shassan5287
    @shassan5287 2 ปีที่แล้ว +1

    Exactly the video I was looking for since getting the K3iii :)

  •  ปีที่แล้ว +1

    thanks for the tests

  • @coolcat23
    @coolcat23 2 ปีที่แล้ว +3

    Nice. Would have been good to accompany this with a sharpness analysis, i.e., check whether the screw-drive AF results are as good as the SDM results.

    • @seanc8054
      @seanc8054 2 ปีที่แล้ว

      id like to have known what the hell a screw drive is, cuz ive no idea wtf this entire video is supposed to be doing? i just bought a pentax K-5 and was looking for videos on it, and ran across this one, dunno why i clicke don it, i dunno anything about cameras right now, i just am starting to get into it. sometimes i think smart need to pretend they are dumb right before they do a video like this because half of everyone that watches it will be dumb, 486 views, and 29 thumbs up from smart people the rest were like me, wtf is happening :(

    • @HarisF1
      @HarisF1 2 ปีที่แล้ว +1

      @@seanc8054 A quick Google search would fix that for you. Stop being lazy.

    • @n_3719
      @n_3719 ปีที่แล้ว +1

      @@seanc8054 late but i hope this information is still useful. screw drive is a type of af motor. its integrated into the body while sdm is inside the lens. the sdm motor is prone to failure but you could "convert" the lens to screw drive when it fails

  • @jackcieslawski1076
    @jackcieslawski1076 2 ปีที่แล้ว +1

    thank you , very informative

  • @doncoombez
    @doncoombez 2 ปีที่แล้ว +1

    Love it!

  • @allthelux
    @allthelux 2 ปีที่แล้ว +1

    Can this be generalized to all SDM -> Screwdrive conversions, or just the lens and body combinations you tested?

    • @PentaxTips
      @PentaxTips  2 ปีที่แล้ว +2

      Although I would love to extrapolate, since I only have the one lens, my sample size is an n of 1.
      However, knowing the similar technology employed on the earlier SDM lenses (the ones capable of converting) I am reasonably confident in saying "yes - the screwdrive operates faster and more reliably than their SDM autofocus".

    • @allthelux
      @allthelux 2 ปีที่แล้ว +1

      @@PentaxTips That's very surprising, as I thought SDM technology was a step up from the screwdrive. Thank you for a great video and test!

    • @PentaxTips
      @PentaxTips  2 ปีที่แล้ว +4

      @@allthelux I guess it all depends on what you want to get out of the lens. Speed or silence!

    • @coolcat23
      @coolcat23 2 ปีที่แล้ว +1

      @@allthelux As PentaxTips said, it is about priorities, but also note that Pentax use the "SDM" moniker for a wide range of AF implementations. There are really slow ones using micro-AF motors and really fast ones using big ring motors.

    • @HarisF1
      @HarisF1 2 ปีที่แล้ว

      @@coolcat23 When people talk about the slow SDM they're usually discussing the system used in the older DA* lenses as well as the DA 17-70. This one is more prone to failure than other types of focusing motor they've used in their 'SDM' lenses.