45mm F/1.8 not stopping down?

Discussion in 'Native Lenses' started by kponds, Nov 26, 2013.

  1. kponds

    kponds Mu-43 Regular

    Mar 18, 2013
    Sometimes when I mount my 45mm, it does not stop down. Meaning, if I dial in F/2.8, the photo ends up 1.3 stops overexposed with the DoF of F/1.8. If I dial in F/4, the photo ends up 2.3 stops overexposed with the DoF of F/1.8. But if I dial in F/1.8, it's fine. If I compose a shot which meters neutral at F/1.8 1/200th and 200 ISO, but then dial in F/16 1/200th 200 ISO, I get a neutral exposure.

    Logically, I think the aperture blades aren't moving.

    I don't think it's "sticky aperture blades", because it only happens sometimes, and if I dismount/remount the lens, or sometimes just reboot the camera, it fixes itself.

    Has anyone seen this? I've experienced it on 2 E-M5 bodies, and none of my other lenses have this problem.

    I really haven't used this lens that much, and it certainly hasn't experienced any trauma.
  2. greenarcher02

    greenarcher02 Mu-43 Veteran

    Feb 13, 2012
    Manila, Philippines
    I experienced "sticky"-like behavior in my 45mm as well, but it has something to do with manual focus. Sometimes when I turn the ring slowly, the camera sees the supposed change in focus, but the lens elements are not moving, so the focus point doesn't actually change.... But it's fine for auto focus.

    Is this a common problem with the 45mm? The sticky elements and stuff?