O45 focus speed

Discussion in 'Native Lenses' started by hwan, Dec 22, 2014.

  1. hwan

    hwan Mu-43 Regular

    Sep 20, 2014
    St Louis, MO
    How fast is the focus speed of the Olympus 45mm in low light? Particularly compared to the 12-40, 17mm, and Nocticron. I just received the Nocticron and find the focusing too slow on my E-M1. I own the other 2 as well and they are very fast to AF, particularly the 17mm. I'm using it mostly to shoot my kids indoors. While the 12-40 is more than fast enough to AF, the 2.8 forces my iso higher than I would like. I wonder if the O45 will be better for me. 1.8 would be fast enough to get my iso down to an acceptable range.
  2. pellicle

    pellicle Mu-43 Hall of Famer

    Feb 10, 2010
    Kiillarney, OzTrailEYa
  3. EarthQuake

    EarthQuake Mu-43 Top Veteran

    Sep 30, 2013
    The 42.5 has a good deal of glass to move around, so when it hunts, it can be a bit sluggish. The trick is to make sure you have a point of contrast to focus on to avoid hunting, then I find the AF speed is just fine. The 45mm is faster to cycle from near to far, but if it gets caught hunting it can go quickly back and forth, back and forth, back and forth without getting a lock, so again making sure you have a point of contrast is really the most important thing.
  4. EarthQuake

    EarthQuake Mu-43 Top Veteran

    Sep 30, 2013
    Just tested a bit, changing focus from an object about 3 feet away to one about 9 feet away in my dimly lit living rooming, metering about 1/160 at 1.8 & ISO 3200.

    45mm and 42.5mm focus speed is about the same, the 45mm might be a tiny amount faster. More interesting, while the 12-40mm is faster than both, its yet again, only fractionally faster.

    This makes me wonder if you've compared the two lenses directly focusing on the some subject, or if you're using anecdotal evidence, for instance, one day trying to focus with the 42.5mm on a completely different subject in lower light and coming to the conclusion that its slower than the 12-40, which was shot on a different day with different light/subject. Not saying this is what you've done, but I would suggest doing some more controlled testing before drawing conclusions to be sure.

    One other thing to note is that the 42.5mm is the loudest of these lenses, which may give the impression that it is noticeably slower without actually being so.
  5. hwan

    hwan Mu-43 Regular

    Sep 20, 2014
    St Louis, MO
    My tests are by no means very controlled. I'm just trying to the pictures of my kids. Typically I rely on the face detection for focusing. The 12-40 almost always goes straight to being in focus while the Nocticron always seems to go the wrong way first and then goes to focus.
  6. barry13

    barry13 Super Moderator; Photon Wrangler Subscribing Member

    Mar 7, 2014
    Southern California
    (emphasis added)

    That's typical of CDAF focusing without PDAF; makes me wonder if your E-M1 is using CDAF only on the Nocticron and PDAF+CDAF on the 12-40mm.

  7. jyc860923

    jyc860923 Mu-43 Hall of Famer Subscribing Member

    Feb 28, 2012
    Shenyang, China
    I think it's due to the large DOF of the 12-40, with even larger DOF, the 14-45 /3.5-5.6 I used to own almost never hunt.
  8. bigboysdad

    bigboysdad Mu-43 All-Pro

    Aug 25, 2013
    Sydney/ London
    If using the touch screen to focus on a particular part of the image, then the 45 is fine indoors, never had a problem in those circumstances.
  9. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    One other thing of note with the Oly 45, while the firmware notes say nothing about it the focusing speed was greatly increased on my E-M1's going from 1.0 to 1.1 (lens firmware) in low light, before the firmware update it hunted (a controlled forced low light situation in an unchanging environment) after it would hunt past *once* then return to perfect focus an instant later rather than racking through the full range and returning the other way.

    Thus I suspect focusing speed has as much to do with firmware version as anything else in low light, I've never had many problems in good lighting conditions.
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