Zeiss Ikon ZM focus strangeness

[piero2025]

Hi,

just got my Zeiss Ikon ZM back from Zeiss after a CLA, and I am noticing an issue - When focusing an object at infinity and setting the focus ring on the lens at infinity (does not rotate any further), the split image in the finder is in focus (no more split double lines etc) BEFORE the lens ring reaches infinity.

It used to be slightly so before the CLA, there was a hint of further rotation after the image was in focus in the finder, so it used to be that whatever line was in the finder, would be in focus slightly before the end of the rotation of the ring, and when I would rotate it all the way, the line would become slightly blurred (the "second image" of the line would slightly start to shift.

Now, if I rotate the focus ring all the way to infinity, the line becomes double, that is, there is a copy of it right to the side of it.

So what do I trust? The focus ring? The lens? Could it be that the lens is LTM on an adapter? The adapter is from Leica though, and I get the same thing from two lenses...

My humble Bessa R does not do it with the same lenses.

 

[piero2025]

Reading through the sticky posts...the camera is actually right? The infinity on the lens really is a very very far place? I was focusing at something about 50 meters away.

 

[Coldkennels]

That just sounds like a rangefinder in need of calibration to me. If the lens is at infinity, the rangefinder should line up perfectly when pointed at a far-away object (the moon is always a good choice). If it isn't, something needs adjusting.

It's important that you do this with a "known good" lens, though - something that you know isn't out of spec. Over the years I've had one or two lenses that don't quite interact with the rangefinder properly, so - for example - I could test one camera body with 10 lenses and get a perfectly lined-up rangefinder at infinity with 9 of them, but one is slightly out of line at the infinity stop.

If your Bessa R's rangefinder is lined up at infinity with both lenses and the Zeiss is not - and the results from the Bessa are in focus - this suggests that it's the ZM that's wrong. This means Zeiss messed up and the camera needs to go back to them to have the rangefinder reset.

Personally, I think it's worth learning to do it yourself. It's not uncommon for rangefinders to be knocked out of alignment over time; I had to readjust my Leica IIIg just last night, actually. Here's some instructions for doing it on the ZM; there's also a video for it on Youtube, if that's more your thing.

Buy yourself the right tools, take it slow, and you'll probably never have to send the ZM back to Zeiss again.

 

[Out to Lunch]

First things first: remove the adapter and go through the same motions with m-mount lenses. Cheers, OtL

 

[piero2025]

Personally, I think it's worth learning to do it yourself. It's not uncommon for rangefinders to be knocked out of alignment over time; I had to readjust my Leica IIIg just last night, actually. Here's some instructions for doing it on the ZM; there's also a video for it on Youtube, if that's more your thing.

Buy yourself the right tools, take it slow, and you'll probably never have to send the ZM back to Zeiss again.

This is golden! Thanks!

 

[piero2025]

Personally, I think it's worth learning to do it yourself. It's not uncommon for rangefinders to be knocked out of alignment over time; I had to readjust my Leica IIIg just last night, actually. Here's some instructions for doing it on the ZM; there's also a video for it on Youtube, if that's more your thing.

Buy yourself the right tools, take it slow, and you'll probably never have to send the ZM back to Zeiss again.

Out of curiosity - is it a thing to do that yourself on Leicas?

 

[piero2025]

On a colder head…I pointed the camera to something farther away (60 meters) and focus is there. I’ll run a roll through the camer and report back.

 

[Sonnar Brian]

The Zeiss has a long base rangefinder in it, and is more accurate than the Bessa.
You need a test target 100m or so distance. An aircraft in flight is a good test.

 

[piero2025]

The Zeiss has a long base rangefinder in it, and is more accurate than the Bessa.
You need a test target 100m or so distance. An aircraft in flight is a good test.

It's gotta be it...I'll report back after the test roll.

 

[Coldkennels]

Out of curiosity - is it a thing to do that yourself on Leicas?

I've always done it - Leicas, Canons, Leotaxes, FEDs, Zorkis, doesn't matter. If you've got the right tools and know what you're doing, it's not the toughest thing in the world.

I do recommend the moon on a clear night as your infinity test, though. That works well.

I used to live in a harbour town years back, and my living room window overlooked the harbour... I could use the lights of a dock almost 2.5km away as an infinity test from the comfort of my table. That was convenient.

 

[Sarcophilus Harrisii]

I have no experience with the ZI rangefinder. But it uses the M bayonet, and takes Leitz lenses. I'll just make the point that even pre M series, some of the Leitz screw mount lenses such as (to name a couple) the 9cm Elmar and 13.5cm Hektor had focusing scales calibrated to 300 feet (100 metres) before hitting their infinity stops. Leitz were not being self indulgent by denoting this level of precision. If your ZI rangefinder is not aligning to infinity when you aim it at a 50 metre target I would suggest there is a very good reason for that. It shouldn't! Try a focus target a kilometre away. Personally, I use a telescope loupe (small monocular) to magnify a viewfinder enough so that I can see minute differences in long range focus. Consider the possibility that the resolution of the rangefinder at long distances exceeds the ability of your unaided vision to detect minute alterations in set distance. Thus, don't try to alter its calibration, until you're first absolutely certain it is warranted.
Cheers,
Brett

 

[Rob-F]

I do recommend the moon on a clear night as your infinity test, though. That works well.

The moon is great for this, but if I want to check my rangefinder in the daytime, I focus on a television transmitter tower about five miles away. The international orange of the tower contrasts nicely with the blue sky, and the thin structural members of the tower make it easy to see when it is in perfect coincidence in the rangefinder! Even if it is only one mile away, that is enough for a good calibration.