Bower 7.5mm lens issue? Debris visible


New to Mu-43
Apr 8, 2014
I'm having an issue with a lens I sold second hand. The guy who bought it sent me 2 weird photos and said when he focuses to infinity he can see a rounded black line on the right of the frame

What could be wrong here? Could it be the built in lens hood is slightly ajar, an aperture blade is sticking, maybe the lens is focusing past infinity? I asked if he was using an adapter and he said no. I don't know anymore specifics but am going to suggest he takes it to a camera shop to see what they think.

It's not an expensive lens but at this point a waste of time and money for me to have to eat the price of round trip shipping if it's either a simple fix or it's just the way this lens is. He said it was decentered but that would be pretty insane to cause this issue and I never observed this phenomenon when I owned the lens.

Has anyone ever seen this in a lens before?

First photo: not focused to infinity
Second photo: focused to infinity (or past?)
Third photo: one I took a while ago with the lens


  • Screenshot_20200119-094603.png
    39.3 KB · Views: 66
  • Screenshot_20200119-094608.png
    43.5 KB · Views: 71
  • P1000500.JPG
    348.8 KB · Views: 70

barry13 Editor
Mar 7, 2014
Southern California
Real Name
Hi, looks like vignetting caused by sensor (IBIS) movement.
Making sure that
A. IBIS setting is set to 7 or 8mm
B. The lens hood, if any, is correctly installed. That's the most likely culprit if it's always in the same place.

However, you can never completely eliminate it from 100% of shots on some lenses, unless you disable IBIS.
Links on this page may be to our affiliates. Sales through affiliate links may benefit this site.
Mu-43 is a fan site and not associated with Olympus, Panasonic, or other manufacturers mentioned on this site.
Forum post reactions by Twemoji:
Forum GIFs powered by GIPHY:
Copyright © Amin Forums, LLC
Top Bottom