Sigma 30mm vs P20mm AF speed

Discussion in 'Native Lenses' started by deacon, Aug 14, 2015.

  1. deacon

    deacon Mu-43 Regular

    Jul 7, 2015
    Opinions of the 20mm AF speed seem range from "not a big deal" to "unusable". Does anyone out there have experience both the Sigma 30 and the P20? How does the AF compare?

    I've got the first gen Sigma 30mm and really like it. I have no problems with it's AF speed and I like the pictures I get with it. My only issue is ergonomics. It's ribbed for grip right at the base, and it's super annoying with my GM1 w/ franiec grip.

    I know the 20mm is a stout little guy, but it's smooth at the base. It will be crowded, but not as uncomfortable.

  2. agentlossing

    agentlossing Mu-43 Hall of Famer Subscribing Member

    Jun 26, 2013
    Andrew Lossing
    The 20mm AF is slower than the 30mm f2.8, whether it's so much slower as to be "unusable" is up to the shooting situation, but I don't think it is. It can be an annoyance, but not the end of the world.

    The 20mm is uncomfortable on the GM cameras, though, at least with the Panny grip. I think the 15mm f1.7 would be the ideal lens for these cameras. Pity it's so pricey!
  3. tkbslc

    tkbslc Mu-43 Legend

    It's quite a bit wider focal length (30mm is 50% longer than 20mm). If you like 30mm, perhaps a new style 30mm is better? Also they have a 19mm if you want the wider focal length.
  4. MoonMind

    MoonMind Mu-43 Top Veteran Subscribing Member

    Oct 25, 2014
    I own and like both lenses; the Sigma is faster to focus, but the Panasonic's AF speed is absolutely sufficient in good light, especially on Panasonic bodies. As soon as it starts to hunt, the 20mm appears sluggish by comparison, but that's not that common as long as you use single-point S-AF. C-AF with the 20mm isn't feasible in my view.

    But the IQ of the 20mm is even better than the 30mm - though in a way, I'd say they're quite similar, sharp, contrasty, rather analytical (instead of vibrant or warm - or cold, come to that). For street and documentary, I'm rather fond of those qualities.

    I think the 20mm will perform nicely on the GM1, however, it's even thicker at the base than the 30mm, so if the Franiec grip is a necessity for you, you may find the Panasonic more cumbersome than the Sigma. Pity - as a lens, it's well worth owning.

  5. ivoire

    ivoire Mu-43 Hall of Famer Subscribing Member

    Aug 6, 2011
    Naperville, IL
    As I have both, I'm in agreement with MoonMind. The 20mm is a bit large on my GM1 but a very convenient/small pkg. The 20mm or 30mm won't allow the camera to sit flat as they protrude below the camera base. The 20mm is much better for street use and isolating subjects due to f1.7. I have a small Chinese stick-on grip on the GM1 and my finger is wedged between it and the lens while gripping the body with either lens mounted. I find it actually stabilizes my grip for one handed shooting.
    Last edited: Aug 14, 2015
  6. deacon

    deacon Mu-43 Regular

    Jul 7, 2015
    Thanks All!

    I've got the 14mm 2.5 and the 30mm. I find the 30mm too long sometimes and the 14mm is only marginally better than my 12-32. When I use the 14mm it's usually in situations (interiors and architecture) where the 12mm is more suitable anyway. I'm considering selling both and replacing them with the 20mm or the 25mm f1.8. The Oly is longer and heavier, but narrower. I've spent some (lots of) time in the showcase threads, and to me the 20mm has the edge. Just trying to get a frame of reference for how slow AF is.

    I too kinda like this about the 30, but it's the texture that ruins it.

    You may be right!:)
  7. davidzvi

    davidzvi Mu-43 Hall of Famer

    Aug 12, 2012
    Outside Boston MA
    Sigma is faster no question. Usable or not comes down to personal perspective AND subject movement. It would be far from my first choice for little kids for example.

    The Sigmas (both the 19mm and 30mm) are 2.4mm thinner in diameter, so they would 1.2mm more room for your fingers.
  8. tkbslc

    tkbslc Mu-43 Legend

    I've owned both. The 25mm f1.8 is just as sharp as the 20mm, if not sharper. The 25mm also has smoother bokeh. The AF difference is like night and day. One is slow and noisy, the other is instantaneous and silent. I have been through quite a few lenses, and I actually think the 25mm f1.8 has the fastest AF in the m4/3 system. Quite a contrast coming from a 20mm, let me tell you.

    The 20mm has just been around so long that there is a lot more work done with it. The 25mm is new, came out in 2014. I agree the sample thread is far more interesting for the 20mm. But that's down to the photographers and history more than the lens.
    • Agree Agree x 2
  9. ahinesdesign

    ahinesdesign Mu-43 Top Veteran

    Dec 6, 2011
    NC, USA
    Like everyone else has said, the 30mm focus is much faster than the 20mm. The 20mm can be frustrating at times, but its usually a non-issue. Image quality can be similar, but I found the 30mm to have much more contrast and to blur out of focus areas a little more at the same subject distances (it should being 50% longer). The 30mm doesn't have the swirly blur that the 20mm does near the minimum focus distance.

    The 30mm "Art" might be better with the smooth barrel, although the 20mm II seems a bit smaller than the original 20...
  10. NWright

    NWright Mu-43 Veteran

    Jan 13, 2014

    I've owned all three :) - that is - the 25mm f1.4, 25mm f1.8 and the 20mm. I can honestly say I like the output (rendering, pop, fairy dust, whatever you want to call it) from the 25 f1.4 the most.

    HOWEVER, I find over and over that I like the FOV of the 20mm significantly more than either of the 25mm lenses and for that it ends up on the camera more often than my 25mm f1.4.

    The difference, I've read, in FOV of these lenses is a bit deceiving because the 20mm is supposedly a touch wider than it is "supposed" to be. Maybe I should just get the oly 17 f1.8 and be done with all of them :).

    As far as AF is concerned, yes the 20mm is slow if it's dark or if it's light and you want to take a picture of something in motion by "locking onto it" while it's in motion.
    • Like Like x 1
    • Agree Agree x 1
  11. GFFPhoto

    GFFPhoto Mu-43 All-Pro

    Feb 24, 2013
    I think the focus speed complaints about the P20 can get a bit overblown, but yes its one of the slower focusing lenses in a fast focusing system.
    • Agree Agree x 2
  12. svenkarma

    svenkarma Mu-43 Top Veteran

    Feb 5, 2013
    mark evans
    The P20 autofocus is sluggish on too regular a basis imho. I sold it with no regrets.

    I've only used the 12-32 briefly, but apart from the manual focus kludge I was impressed. Maybe the Sigma 60 would make a good replacement?

    Sizewise, it sounds like the O25 would make more sense than the P25.
  13. davidzvi

    davidzvi Mu-43 Hall of Famer

    Aug 12, 2012
    Outside Boston MA
    If the rest weren't just so darn fast the speed of the P20 wouldn't be an issue.
    • Agree Agree x 3
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