What kind of issue is this called and can it be fixed?

wonjohnsoup · Joined: 09 Feb 2016 Posts: 1

I just purchased a new Zonlai 25mm F1.8 and there's this odd problem I've never encountered. I measured out 7 feet from some books and set my distance scale to 7 feet. Out of focus. So I move the focusing ring until it's in focus and I bring the camera down and see "3 feet" on the scale. Ok. But when I bring it back up to my eye, its out of focus again. Then I realized that I can literally tilt the lens up and down a little and the focus shifts, but without the focus ring moving. It's quite dramatic, too, how far the focus can shift. I've had this lens less than 12 hours and first noticed it was focusing strangely so I'm guessing this is manufacturer defect. There's also a small visible amount of oil in the gap between the focusing ring and the rest of the body. Is this something a repairer can resolve easily?

visualopsins · Expire: 2021-06-22

Welcome wonjohnsoup!

Maybe a repairer could fix it easily. Depends on what is wrong and repairer skill level. Wink

Sounds like manufacturer defect. Can you return to seller for refund or replacement with good copy?

Ramon · Joined: 01 May 2007 Posts: 71 Location: Kent, UK

Sounds like either a loose lens element or loose focus mechanism.
A 25mm lens only needs a very slight change of position to get a drastic difference in focus.

If it is new then I would suggest that you return it.

calvin83 · Joined: 12 Apr 2009 Posts: 7495 Location: Hong Kong

Return it. It is not uncommon for these lens made by small firm has quality issues.