50 Lux Asph Factory Calibration

[jplomley]

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Forum members, I could use some help on this one. In comparison to my 50 Cron when street shooting, I notice that the DOF partitions rather differently with the Lux. While the DOF partitions around the plane of focus as expected for the Cron, with the Lux all of the DOF is behind the plane of focus. Pulled out the ruler, and sure enough, the Lux is back-focusing 1/2 inch at 2.5 ft. Thinking the RF of my M9 had drifted, I pulled out all my other lenses (28 Cron Asph, 35 Cron Asph, 50 Cron, 90 Elmarit). Every one of them was spot-on, with DOF partitioned as one might expect. Odd. So I borrowed a friends 50 Lux Asph which had been purchased ~ 3 months after mine. It exhibited the exact same attributes as my copy (i.e. back-focusing 1/2 inch at 2.5 ft). Now for street shooting I usually don't worry about these things, however, I've noticed that even at 10 ft, I have no DOF in front of the plane of focus, so that faces are a bit too soft when focussing on the torso. Very frustrating, however, given the fact that both copies of the lens tested display this characteristic, Leica must be calibrating them to this specification. But why? If I have Leica adjust the calibration, will this negatively impact some other attribute of the lens?

[don daniel]

Did you test the lenses only with open aperture or also stopped down a little bit? DOF of the Summilux open is much thinner than DOF of your wide angles. I'm not convinced yet that the problem is not the rangefinder calibration.

[jaapv]

Does Lux mean the Summilux 50 asph? If so, it is quite possible, as this lens is one of the more difficult lenses to calibrate 100%. If it misfocusses send it in to Leica to correct. It may take a while in my experience. But you will still have your Summicron 50 (assuming that is the lens you mean) to tide you over.

[lct]

"50 Cron" and "50 Lux Asph" sound perfectly clear to me.

[jaapv]

Nails on a blackboard. ;( Not as bad as EP though. SX indeed If the lens is out of adjustment we should call it Sux

[jplomley]

Cheers gentlemen

 

Don, I tested all lenses wide open and stopped down to f/5.6 in one stop increments. With the 50 Lux Asph, it was not until f/5.6 that there was enough DOF to cover the intended focus plane. All other lenses were perfect, including the 90/2.8 Elmarit (last version), which also furnishes a very narrow DOF. Note that I have perfect vision, and for these types of evaluations use the Leica 1.4x magnifier. After discovering my friends copy of the 50 Lux Asph exhibited the exact same attributes as mine, I'm convinced these are not being set up properly at the factory. Reluctanly, I shall send it back to Leica Solms (I have doubts about Leica NJ's ability to fix anything properly after a few bad experiences in the past).

[jplomley]

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If the lens is out of adjustment we should call it Sux

 

.....:D...

[Jeff S]

Reluctanly, I shall send it back to Leica Solms (I have doubts about Leica NJ's ability to fix anything properly after a few bad experiences in the past).

 

Call Don Goldberg (DAG) and discuss with him. He worked magic on the tight/sticky focus turn with my 50 Summilux Asph (another somewhat common issue with that lens) and was able to work magic after Leica NJ said they could do nothing.

 

Jeff

[jplomley]

Not sure DAG has the proper tools for calibrating to digital standards.

 

I had heard about the tight focussing with some copies of the 50Lux, fortunately, mine was buttery smooth out of the box. However, I would trade this attribute for a properly calibrated $4K lens.

[jaapv]

I'm with you Jeffry. The 50 asph has floating elements that adjust separately - with very narrow tolerances. I would not trust anybody but Solms to adjust it properly.

[thighslapper]

These lenses are like homing pigeons.

 

I've had 3 and they have all been back to Leica to be fiddled with.

 

The current ... which I have kept ..... is still not spot on at all distances, but the error is not noticeable in normal use.

 

I tend to use either my Nocti or 50/2.8 collapsible as a result. Knowing it's not right just irritates me and I resent using it as a result

 

If I ever get a 50/2 Apo it will be re-homed like the others.....

[jaapv]

Leica CS managed to get mine spot-on - but it took them three months.

[TomB_tx]

This lens is a marvel, but there's a lot to be said for mechanical simplicity too. That's why I'm content to stay with my pre-asph Summilux and Voigtlander 50 1.5. Both have been issue free.

[Jeff S]

Not sure DAG has the proper tools for calibrating to digital standards.

 

But I only suggested a call to start, since I'm confident that Don will give you his straight facts, no BS, on what he can and cannot do. Leica NJ told me a bunch of crap about the impossibility of fixing the tight focusing on my lens, and yet Don fixed it, just the way he said he would when I called first to inquire.

 

Nothing lost but a small phone cost.

 

BTW, Sherry Krauter, who is another dependable Leica service person, will only work on film Ms, as the cost for digital calibration equipment is cost prohibitive for her. Don may tell you something similar about the Summilux, but you won't know if you don't ask.

 

Jeff

[jplomley]

Well, here is an update. One year after purchasing my new 50 Lux Asph I decided to sell and re-buy simply because I do not have the confidence in Leica NJ to fix anything properly. Any lens I have sent them has come back with either the problem not being properly fixed, or the lens being returned in worse condition. I therefore purchased a second copy which initially looked promising. Close-focus and infinity were perfect....DOF partitioned as expected. This was in marked contrast to the previous version where all the DOF was behind the intended plane of focus. However, at mid-distances starting around 5 feet, I am seeing considerable back-focussing with the plane of focus being completely lost. Out of the six Leica lenses I own, I have never seen this issue. This is rather unfortunate, and speaks volumes about Leica's QC on this lens. At this point, I am just going to sell it on and stick with my v5 50mm Summicron which just performs perfectly in every respect....minus the f/1.4 separation and bokeh I was hoping to acquire through my purchase of the Summilux. I was hoping to try the 50 AA as apparently the bokeh at f/2 is far smoother than that produced by my v5 Summicron, more in-line with the Summilux rendering. However, it appears this lens suffers from flare and could take as long as a year to acquire a copy. What is going on at Leica that the QC on two highly desireable lenses is less than stellar? I recently bought a new 90 APO, and it is spot-on right out of the box. No focus issues, focus shift etc. Just a rock-solid performer, which is what I would expect for $4K. So what the hell is the problem with their ability to manufacture and QC check the 50mm Asph focal lengths? All the skilled labour on the Noctilust line

[Jeff S]

Sorry to hear. Next time send your lens to DAG, or at least call him to discuss.

 

Jeff

[k-hawinkler]

Sorry to hear. Next time send your lens to DAG, or at least call him to discuss.

 

Jeff

 

 

Thanks. Does DAG do FLE lenses?

[Erik Gunst Lund]

Strange that a lens should be non linear... I would guess your rangefinder is adjusted wrong, wrong arm length would do exactly as you describe, did you test this on a M (240) live view vs RF?

 

Reason for other lenses not reveling this are many...

[jplomley]

All my other lenses focus perfectly at all distances: 28 Cron Asph, 35 Cron Asph, 50 Cron v5, 90 Cron APO Asph. So doubtful that my M9 is the issue. Even if it were the M9, I would not have them touch it if thats what it takes to achieve a functional 50 Lux Asph, as I'm sure it would be at the detriment of my other lenses. I even borrowed a friends Nocti/0.95 and focus was spot on. It's definitely a QC issue with the 50 Lux Asph.

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Hallo,

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[jplomley]

I do have access to an M240, so will give that a try this weekend.