Odd Focusing Issue - 90 APO Summicron

Several months ago, I purchased a 90 APO Summicron from KEH. It was listed as Excellent, and it was. I used it on several trips and liked to bring it along with my 35 Summilux for their unique looks.

It was tack sharp at every f stop. Then two weeks ago, I was in Toronto and suddenly it didn't have any clear focus at infinity except at f16. I thought that it had to be the M11's recent update, so I changed settings to automatic, then manual. Still no luck.  When I got home I mounted it on SL2 and still the same issue at every f stop.

Eventually I sent it to Leica USA in New Jersey. I just signed the work order to repair. It's just over $300 (USD).

I asked the technician what happened and he said he didn't know exactly, he said it needed "extreme front focusing alignment"

The problem came up very quickly. It worked great on a recent trip. Then suddenly, it didn't. The lens, when not being used, always has the caps on and is kept in a padded compartment of my bag. When it's mounted on my M11 or SL2, the cameras are always gently handled.  At home, it's kept on a shelf free from humidity.

I'm curious how front focus get out of alignment so severely so I can avoid this in the future.  Has anyone else had similar issues?  Are there ways for the not so faint of heart to do this kind of adjustment a home?

Thanks,

-Ted

You bought a used lens and any testing that retailers like KEH do is enough to verify that things work when they buy it. That lens may have been on its way to failure even before you got it.

I've bought all of my gear used for the past five or six years and even though that has allowed me to own Leica gear, which I otherwise could not afford,  I'm aware that anything I have could develop a problem tomorrow. It's just like buying a used car, the tradeoff is risk versus savings.

bs1946 wrote:

You bought a used lens and any testing that retailers like KEH do is enough to verify that things work when they buy it. That lens may have been on its way to failure even before you got it.

I've bought all of my gear used for the past five or six years and even though that has allowed me to own Leica gear, which I otherwise could not afford, I'm aware that anything I have could develop a problem tomorrow. It's just like buying a used car, the tradeoff is risk versus savings.

That's true, I'm still way ahead, but this is the first used Leica lens I've purchased.  I'm still ahead of the game since it was $1500 less than retail and the repair was $300.  I'm mainly curious how the failure happened and what I can do prevent it from happening again.

Thanks!

tedwill48167 wrote:

I'm mainly curious how the failure happened and what I can do prevent it from happening again.

I think only the repair-guy working on your lens can tell this after (partial) disassembly and repair.

Last month I had a pipe in my basement spring a leak after flushing a toilet at the other end of the (64-year-old) house, not directly connected to that pipe. I guess the change in water pressure from the flush was just enough to push an almost-failed section of pipe into outright failure. Something similar, a slight jostle or knock, likely happened with your 90mm.

-Dave-