Kaunzinger
Newbie
Hello, I am looking for some education on the aperture ring characteristics of Leica M lenses. Asking for input from those who have owned/used a good number of M lenses or ideally from those who actually work on them.
I am still building my Leica outfit starting from M9 and now an M-P240. Of the lenses that I own or have borrowed, I have noticed some inconsistencies in how the aperture ring stops are fitted/adjusted from the factory. Here are my several examples:
Case #1:
I own a current Summicron 35/2 ASPH in chrome. A very nice lens. Opening it all the way wide, the aperture ring clicks in at the f/2 mark and then can rotate just a little more until it hits the hard stop. When letting go of the ring it just barely stays in the position beyond f/2 by friction. It does not snap back into the f/2 detent position unless it is nudged ever so slightly back to that detent position. And on the other end when stopping down to f/16, it is the same where it can click to that position and then rotate a little more past until it hits the hard stop. Letting go of the ring gives the same result where friction just barely holds it beyond the f/16 detent. And a very slight coaxing with the fingers will cause it to snap back into the detent. So, I've always assumed this as a proper lens adjustment, where the aperture ring is basically 'centered' and the detent (clicks) versus hard stops behave identicaly at either end.
Case #2:
I own a current Summilux 50/1.4 ASPH in chrome. My favorite lens. The aperture ring on this one behaves similar to the Summicron above, except that it has a pinch less over-travel beyond the detents until hitting the hard stops. In other words, the aperture will turn just beyond the detents at f/1.4 or f/16 until hitting the hard stop, but in this case it immediately snaps back into the detent when letting go of the aperture ring. Again the aperture ring can be called 'centered', having the same behavior at either end of the range. And again, this adjustment (if that is what it is) seems proper to me...maybe with an even closer tolerance build than the Summicron, so to speak.
Case #3:
A beautiful old Elmar 135/4 that I picked up. (I just had this serviced at Leica USA for CLA.) The aperture ring pretty much stops right at the click detents at f/4 and f/22 with little or no over-travel. The ring is adjusted 'centered' to both ends of the aperture range. I also consider this one normal and acceptable.
With all of the three lenses above I never even thought about this issue. Until I noticed a significant difference in the two cases below:
Case #4:
I purchased a new Elmarit 28/2.8 because I wanted something small to travel but still with great performance. On my initial inspection after unboxing, I rotated through the aperture range and noticed that the ring both clicked and hard-stopped exactly right on f/16. OK, nice, tight, just like my old Elmar. So then I moved the ring towards the wide open end and found that the ring rotated way beyond the f/2.8 detent..by about 1/2 of a stop distance. When letting go of the ring of course it would not click back into the proper f/2.8 detent. It was far beyond. Furthermore, the over travel difference made a significantly larger opening in the lens iris when moving beyond the f/2.8 detent to the hard stop. Possibly a 1/2 stop larger of an opening. All of this immediately caught my attention and bothered me a bit. I called Leica USA about it and after my explanation, their reply was that 'there is some tolerance involved'. That short answer did not satisfy me and I ended up returning the lens for a refund. My thought was that it was a poorly adjusted sample, hopefully a rare occurrence. That happened about a year ago.
Case #5:
Fast-forward to last week. A friend put down $5000 for a Summilux 35/1.4 FLE. Wow...can I see it? So I touch it, go through the motions and notice a tight/immediate stop at f/16... but then a large amount of aperture over travel at the f/1.4 end. Pretty much identical as what I experienced in the Elmarit 28. And the iris condition was also the same, meaning that the aperture ring over travel noticeably opens the lens iris larger than what it is at the f/1.4 detent. ...I didn't say anything to my friend. Because he paid $5k for it and also because I don't really know what should be expected.
Summary and Questions:
To me, this over-travel condition seems very strange. Especially having this at the wide-open end. Probably most of us rely on that hard stop at wide open in order to confirm our aperture settings without having to look, no? So then at the hard stop on the two lenses in question, will the true aperture value be f/2.8 (or f/1.4) or will it be more open than what the lens was designed (or calibrated) for? And/or, could this extra light being let in cause possible loss of contrast or increased chance of flare? Is the aperture blade opening calibrated during final adjustment and how then are do the ring/detents/hard stops come together for adjustment? Are the final results dependent on the assembling technician and his final fitting technique? Or are certain characteristics like this a 'personality trait' of each specific Leica lens design? I am curious if this variance in aperture adjustment (or design) is typically seen from lens to lens? How do your lens samples behave in this regard? And why have I never noticed this in most all of the other-brand lenses I've used?
Asking those who may know better than I.
Thank you very much.
I am still building my Leica outfit starting from M9 and now an M-P240. Of the lenses that I own or have borrowed, I have noticed some inconsistencies in how the aperture ring stops are fitted/adjusted from the factory. Here are my several examples:
Case #1:
I own a current Summicron 35/2 ASPH in chrome. A very nice lens. Opening it all the way wide, the aperture ring clicks in at the f/2 mark and then can rotate just a little more until it hits the hard stop. When letting go of the ring it just barely stays in the position beyond f/2 by friction. It does not snap back into the f/2 detent position unless it is nudged ever so slightly back to that detent position. And on the other end when stopping down to f/16, it is the same where it can click to that position and then rotate a little more past until it hits the hard stop. Letting go of the ring gives the same result where friction just barely holds it beyond the f/16 detent. And a very slight coaxing with the fingers will cause it to snap back into the detent. So, I've always assumed this as a proper lens adjustment, where the aperture ring is basically 'centered' and the detent (clicks) versus hard stops behave identicaly at either end.
Case #2:
I own a current Summilux 50/1.4 ASPH in chrome. My favorite lens. The aperture ring on this one behaves similar to the Summicron above, except that it has a pinch less over-travel beyond the detents until hitting the hard stops. In other words, the aperture will turn just beyond the detents at f/1.4 or f/16 until hitting the hard stop, but in this case it immediately snaps back into the detent when letting go of the aperture ring. Again the aperture ring can be called 'centered', having the same behavior at either end of the range. And again, this adjustment (if that is what it is) seems proper to me...maybe with an even closer tolerance build than the Summicron, so to speak.
Case #3:
A beautiful old Elmar 135/4 that I picked up. (I just had this serviced at Leica USA for CLA.) The aperture ring pretty much stops right at the click detents at f/4 and f/22 with little or no over-travel. The ring is adjusted 'centered' to both ends of the aperture range. I also consider this one normal and acceptable.
With all of the three lenses above I never even thought about this issue. Until I noticed a significant difference in the two cases below:
Case #4:
I purchased a new Elmarit 28/2.8 because I wanted something small to travel but still with great performance. On my initial inspection after unboxing, I rotated through the aperture range and noticed that the ring both clicked and hard-stopped exactly right on f/16. OK, nice, tight, just like my old Elmar. So then I moved the ring towards the wide open end and found that the ring rotated way beyond the f/2.8 detent..by about 1/2 of a stop distance. When letting go of the ring of course it would not click back into the proper f/2.8 detent. It was far beyond. Furthermore, the over travel difference made a significantly larger opening in the lens iris when moving beyond the f/2.8 detent to the hard stop. Possibly a 1/2 stop larger of an opening. All of this immediately caught my attention and bothered me a bit. I called Leica USA about it and after my explanation, their reply was that 'there is some tolerance involved'. That short answer did not satisfy me and I ended up returning the lens for a refund. My thought was that it was a poorly adjusted sample, hopefully a rare occurrence. That happened about a year ago.
Case #5:
Fast-forward to last week. A friend put down $5000 for a Summilux 35/1.4 FLE. Wow...can I see it? So I touch it, go through the motions and notice a tight/immediate stop at f/16... but then a large amount of aperture over travel at the f/1.4 end. Pretty much identical as what I experienced in the Elmarit 28. And the iris condition was also the same, meaning that the aperture ring over travel noticeably opens the lens iris larger than what it is at the f/1.4 detent. ...I didn't say anything to my friend. Because he paid $5k for it and also because I don't really know what should be expected.
Summary and Questions:
To me, this over-travel condition seems very strange. Especially having this at the wide-open end. Probably most of us rely on that hard stop at wide open in order to confirm our aperture settings without having to look, no? So then at the hard stop on the two lenses in question, will the true aperture value be f/2.8 (or f/1.4) or will it be more open than what the lens was designed (or calibrated) for? And/or, could this extra light being let in cause possible loss of contrast or increased chance of flare? Is the aperture blade opening calibrated during final adjustment and how then are do the ring/detents/hard stops come together for adjustment? Are the final results dependent on the assembling technician and his final fitting technique? Or are certain characteristics like this a 'personality trait' of each specific Leica lens design? I am curious if this variance in aperture adjustment (or design) is typically seen from lens to lens? How do your lens samples behave in this regard? And why have I never noticed this in most all of the other-brand lenses I've used?
Asking those who may know better than I.
Thank you very much.
