Link to a blog post by Heinz Richter reporting on his visit to Wetzlar and Leica's manufacture of aspheric lens elements, the tolerances, glass types, grinding etc
Really?
"During my visit to Leica I was able to obtain a wealth of information about what they are doing to make lenses as good as possible. That amounts to tolerances and a level of precision simply not available from other manufacturers. This takes place on two levels, the mechanical and optical precision. For reasons of greater accuracy, Leica does no utilize any assembly lines. Instead, all production and assembly steps are done on individual work stations, usually in clean rooms with the work station functioning by design as additional clean environments."
So you are saying that Zeiss, Nikon, Canon, Olympus, etc. are unable to achieve these levels of precision or really is it that if they did their lenses would be as expensive as Leica?
I'm not sure Leica has some special manufacturing ability that other manufacturers cannot achieve, they likely can, they just choose not to for cost reasons.
I can't wait until Roger publishing the variation score for those Leica M lenses. It would dispel some of these superior mechanical and optical precision non-sense.
What I know is that manufacturing tolerances of Leica M lenses are about half of those of the Zeiss ZM. However with many lenses Zeiss designs are simply better and the T* coatings are just the best. There are many M lenses that are known for bad mechanical designs and they tend to fall apart like the 50 lux or 28 cron.
"0.003 microns or 0.000075mm"
"0.005 micron or 0.00015mm"
Wait, what? Seriously, for a piece of marketing fluff passed off as a tour, at least get your measurements right. Especially since dealing with the metric system. This is a joke.
jhinkey wrote:
I'm not sure Leica has some special manufacturing ability that other manufacturers cannot achieve, they likely can, they just choose not to for cost reasons.
They do have unique machines to grind aspherics. They probably need to in order to achieve the optical performance in the small package of M lenses.
edwardkaraa wrote:
There are many M lenses that are known for bad mechanical designs and they tend to fall apart like the 50 lux or 28 cron.
This is part of the masochism of shooting Leica; the Leica paradox.
Fortunately my 28 Cron hasn't wobbled apart, yet. But it is a rather easy fix, albeit with the right tool. The 50 Lux has irked me much more, but it remains the 50 I reach for first and continue to use the most often...
edwardkaraa wrote:
I actually believe that tolerances are very tight. Have you ever heard of a decentered M lens?
I'm not disputing that Leica have tight manufacturing tolerances, but I was just teasing about the MTFs which I believe aren't direct measurements. Also, the writer got the bit about 1 micron being 1/100 mm wrong (it's 1/1000).
I'm sure that Leica uses the same machine tools to cut, grind, & polish, etc. components as everyone else does. I'm not sure how assembly lines are any worse than work stations as far as tolerances are concerned because, unfortunately, human beings introduce variability, clean or not.
edwardkaraa wrote:
I actually believe that tolerances are very tight. Have you ever heard of a decentered M lens?
Edward, I have (50 AA, Noct 50, SEM 18, etc.). I think for most Leica photographers are less fussy about such a thing. I think part of it is due to the rangefinder nature. If anything is wrong, it's probably because you focus it wrong or the RF is out of alignment; few would have thought of the lens being de-centered. With the M240, more precise test for de-centering can be done. For me, I'm lucky that I have not received any bad lens from either Zeiss or Leica yet, or even Sony for that matter .
rscheffler wrote:
This is part of the masochism of shooting Leica; the Leica paradox.
Fortunately my 28 Cron hasn't wobbled apart, yet. But it is a rather easy fix, albeit with the right tool. The 50 Lux has irked me much more, but it remains the 50 I reach for first and continue to use the most often...
Fingers crossed, Ron I always wondered how such high build quality and tight tolerances can end up with some obviously weak elements that are most likely to fail sooner or later.
hiepphotog wrote:
Edward, I have (50 AA, Noct 50, SEM 18, etc.). I think for most Leica photographers are less fussy about such a thing. I think part of it is due to the rangefinder nature. If anything is wrong, it's probably because you focus it wrong or the RF is out of alignment; few would have thought of the lens being de-centered. With the M240, more precise test for de-centering can be done. For me, I'm lucky that I have not received any bad lens from either Zeiss or Leica yet, or even Sony for that matter .
Don't underestimate the Leica crowd, they're not all rich dentists, you know
I have seen slightly decentered Zeiss lenses, but never a ZM, and I have probably bought almost all of them. Leica lenses can suffer from miscalibration but I haven't heard of any decentering so far, though I don't doubt your words. This is of course a far cry from my Canon and Sony days. In fact Sony have the worst record so far. Every single lens I have bought including all ZA suffered from various degrees of decentering ranging from negligible to outrageous
jhinkey wrote:
So you are saying that Zeiss, Nikon, Canon, Olympus, etc. are unable to achieve these levels of precision or really is it that if they did their lenses would be as expensive as Leica?
.
Well, Roger's current bench tests make the Sony Natives look.......not optimal in quality.
There is copy variation in Leica glass for sure. But I'll be surprised if it's that much. Or even remotely close.
As to Leica M lenses "falling apart"; this is misleading. Like the ZM lenses, the front groups can become loose and you need a special tool to access the screws which need to be tightened. You send it to DAG for under 100 bucks they are like new. Tight. I did this once with 28 cron and SEM 21.
That screws can loosen over time is not the same as a decentered or soft lens.
In general there is no reason to doubt the overall quality and build of modern Leica M lenses is better than any form of Zeiss, let alone Sony.
My two ZM favorites, the ZM18 (TY philber) and ZM35/2 are both just fine. Voightlander is more questionable. I suspect large copy variation there.
thats what Rogers intern Brandon had to say about Leica's QC: I'll just say that from the small sample sizes of leica lenses I've measured (total ~20-25) that's not quite accurate. The tolerances of Zeiss and Leica's consumer lenses are okay to good, but far from "strict." I would consider a "strict" tolerance to be those used in the more expensive $10,000+ low volume lenses produced by companies such as e.g. Jenoptik, Navitar, Corning Advanced Optics, etc. Of the consumer lens manufactures, Canon has the strictest tolerances at the moment, at least on their newer lenses. Some like the 100mm f/2 USM are a trainwreck but others like the 11-24 f/4 are mind blowingly consistent. ...Show more →
Anecdotal, though a good source. We need to see the charts. 11-24 consistency impressive.
These are great tests they are doing. A real service.
The real message is: if you are choosing carefully, which lens to buy, then get it from somewhere it can be returned, and test it right away: if you care.
jhinkey wrote:
So you are saying that Zeiss, Nikon, Canon, Olympus, etc. are unable to achieve these levels of precision or really is it that if they did their lenses would be as expensive as Leica?
Ah, just to clarify, I merely posted a link to a blog with info on the manufacture of aspheric lenses and have no idea what other manufacturers can or cannot achieve.
hiepphotog wrote:
Edward, I have (50 AA, Noct 50, SEM 18, etc.). I think for most Leica photographers are less fussy about such a thing. I think part of it is due to the rangefinder nature. If anything is wrong, it's probably because you focus it wrong or the RF is out of alignment; few would have thought of the lens being de-centered. With the M240, more precise test for de-centering can be done. For me, I'm lucky that I have not received any bad lens from either Zeiss or Leica yet, or even Sony for that matter .
I think you must have terrible luck Hiep. I have not once ever heard of an M-mount lens being decentered... There are other (more minor) issues but not very often. I honestly believe that Leica lens build quality and optics are simply superb. I would also go out on a limb and say that their level of quality is above most other mainstream manufacturers (with the exception of a few product lines). And no, I have not had any Leica Koolaid yet today....
Gary Clennan wrote:
I think you must have terrible luck Hiep. I have not once ever heard of an M-mount lens being decentered... There are other (more minor) issues but not very often. I honestly believe that Leica lens build quality and optics are simply superb. I would also go out on a limb and say that their level of quality is above most other mainstream manufacturers (with the exception of a few product lines). And no, I have not had any Leica Koolaid yet today....
Not my own experience though . I guess I spent too much time on LUF, especially with all the recent posts about the problematic build of the 50 AA. But I have seen reports on de-centered Leica before, most notably from Mr. Chambers .
(50 AA, Noct 50, SEM 18, etc.). I think for most Leica photographers are less fussy about such a thing. I think part of it is due to the rangefinder nature. If anything is wrong, it's probably because you focus it wrong or the RF is out of alignment; few would have thought of the lens being de-centered. With the M240, more precise test for de-centering can be done. For me, I'm lucky that I have not received any bad lens from either Zeiss or Leica yet, or even Sony for that matter 
I always wondered how such high build quality and tight tolerances can end up with some obviously weak elements that are most likely to fail sooner or later.