21 SEM quality control issues?

[darylgo]

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I can say of my own experience that the last 6 Summicron asph 75mm lenses I have had in my possession, all of them were "lemmons". The only used 75mm summicron lenses there are on the market, are the ones sold by their owners, because of the bad sharpness at infinity. Maybe a lot of them thought it was their own fault and that the lens was not good for them , because they were not capable of handeling their specimen, but the search for a used 75mm led me to this conclusion. Of all the people I speak that want to keep their 75mm , all of them have a perfect specimen. 

 

My one sample (used) was terrible also.   For 5 years I have thought of buying another but will now be extra careful.  Thanks.  

 

Another issue is: When a new lens out of the factory has had a knock of some kind; it's fallen ( in his box ) during transport. Could this influence the lens in such way, that there is a difference in sharpness in the corners between two lenses? 

 

My guess is it would not cause any issues unless assembled poorly.  I did receive a new 21 Summilux (in that beautiful Leica packaging) whose aperture ring was stuck, I returned it but prior and with nothing to lose I forced the ring with as much hand pressure possible and it unstuck.  I then tested it with a second copy sent to replace it, and they imaged very closely, each copy slightly different but close enough that both would have been acceptable.    

[Jeff S]

I bought the new Canon 1.4/35mm IS II for my SL, this lens is now supposedly the best 35mm available. I read tests of this lens and the competition such as Sigma Art, for example here:

 

https://www.lensrentals.com/blog/2015/11/lensrentals-reviews-the-canon-35mm-f1-4l-ii-lens/

 

This guy tests many similar lenses and often reports average scores, and for example comparing the Sigma Art and the Canon, probably Canon has a slight upper hand but this does not mean that all Canon specimens are better than the Sigma, as internal variation is greater than the difference between the two makes. However, based on what many of you report here, this is hardly what we discuss, or?

See two posts above yours. The subject has been covered extensively there, for a wide range of focal lengths and brands.

 

Jeff

[Gregm61]

If I start feeling sorry for myself, I can thread this thread and immediately start feeling better. I must be the most lucky person out there with such a good copy of the 21mm f3.4 Super Elmar. 

[DMJ]

I have sent several lenses back to Germany over the years. Some several times until correct. Apart from the delay in the time to come back, Leica have been great about dealing with the problems. Currently have a 24mm f3.8 bought new 7/10/17 back in Germany. I could not match the lines of goal posts at infinity with my M240. All my other lenses are ok. It'll come back in due course.

[TomB_tx]

The only "bad" Leica lens I've had was my first: a fat TeleElmarit I bought new in 1968. When I bought it everything was fine. I added 50 & 35 Summicrons and used them almost exclusively for a few years. When I began using the 90 again along with the others, I always weeded out the 90 shots due to poor sharpness and very low contrast. I ran focus tests on a newspaper and best focus was hard to find - nothing was sharp. So I put it in a drawer for decades.

Maybe 10 years ago I checked it again - still awful. So I sent it to a Leica tech who reported a rear element had shifted out of position. It's been great since he corrected it.

I don't recall any rough handling, but it happened while I owned it.

All the newer Leica lenses I've purchased have been fine, but I've avoided the FLE models as the added complexity of construction means more to go wrong.

[cpclee]

Let me know your thoughts.

 

https://www.l-camera-forum.com/topic/278003-75-summicron-aa-corner-degradation/

 

 

With the 75mm Cron I was lucky. The second sample I tried was perfect. I'll never sell it.

[lct]

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Let me know your thoughts.

https://www.l-camera-forum.com/topic/278003-75-summicron-aa-corner-degradation/

 

If you insist... You're expecting too much re sharpness in the corners at f/2. For better results there you may wish to try a 50/2 apo.

[cpclee]

@Paulus would you also comment on my 75 Summicron as I’d like to know what is normal to expect

 

https://www.l-camera-forum.com/topic/278003-75-summicron-aa-corner-degradation/

 

Personally, knowing a thing or two about statistical variations and manufacturing tolerances myself, I’m perfectly happy with a specimen that is within the manufacturer’s accepted tolerance. Variation can be reduced, possibly at a very high if not astronomical costs, but never completely eliminated.

 

The conundrum faced by lens manufacturers today is that with pixel peeping being so easy, people expect perfection whether or not that is physically or economically feasible. Some manufacturers (like Nikon USA) from what I’ve read have stopped taking in returns based on what the user thinks is or isn’t reasonable.

 

 

I can say of my own experience that the last 6 Summicron asph 75mm lenses I have had in my possession, all of them were "lemmons". The only used 75mm summicron lenses there are on the market, are the ones sold by their owners, because of the bad sharpness at infinity. Maybe a lot of them thought it was their own fault and that the lens was not good for them , because they were not capable of handeling their specimen, but the search for a used 75mm led me to this conclusion. Of all the people I speak that want to keep their 75mm , all of them have a perfect specimen.

 

[cpclee]

Let’s just say that your response there pleases me

 

If you insist... You're expecting too much re sharpness in the corners at f/2. For better results there you may wish to try a 50/2 apo.

[onasj]

Wow, so much activity on this thread suddenly. Thank you for your responses.

 

To address some questions, the first highly decentered 21 SEM was definitely not within Leica tolerances. The bad (upper left) corner was so bad that you could immediately tell even on an iPhone screen without zooming in. I know this because when I showed my Leica dealer a photo of a wall with four focus stars in the corners on my iPhone he saw the one in the upper left and made a sound that can best be described as a spontaneous vomiting noise then promptly agreed that the lens was defective. Also, that bad 21 SEM was softer at any corner at 3.4 using then test than my 28 lux at 1.4, which is very different than the MTF curves indicate.

 

Perhaps it’s not so much that I’ve been unlucky with the 21 SEM but rather that I’ve been so lucky with the other lenses I’ve owned or handled, including the 21 lux, the 28 lux, the 35 lux, the 50 APO (two copies), the 90 APO, and the 135 APO, all of which were excellent by my tests out of the box.

 

All the more reason to make sure your Leica retailer or seller offers a very good return policy!

[Paulus]

@Paulus would you also comment on my 75 Summicron as I’d like to know what is normal to expect

 

https://www.l-camera-forum.com/topic/278003-75-summicron-aa-corner-degradation/

 

Personally, knowing a thing or two about statistical variations and manufacturing tolerances myself, I’m perfectly happy with a specimen that is within the manufacturer’s accepted tolerance. Variation can be reduced, possibly at a very high if not astronomical costs, but never completely eliminated.

 

The conundrum faced by lens manufacturers today is that with pixel peeping being so easy, people expect perfection whether or not that is physically or economically feasible. Some manufacturers (like Nikon USA) from what I’ve read have stopped taking in returns based on what the user thinks is or isn’t reasonable.

 

 

 

IMHO this is absolutely not normal. A lens of this qual;ity should behave well corrected and not like the pictures imply.  In comparison with my M -summiluxapsh 50.:There is no issue like this at 1,4.  I would not buy this 75mm. 

[Paulus]

see below..

Edited October 24, 2017 by Paulus

[Paulus]

 

The conundrum faced by lens manufacturers today is that with pixel peeping being so easy, people expect perfection whether or not that is physically or economically feasible. Some manufacturers (like Nikon USA) from what I’ve read have stopped taking in returns based on what the user thinks is or isn’t reasonable.

 

 

 

If the pixel peeping shows you, what you can expect if you have an enlargement of 2 meter, if you make such enlargements, it would be unwise not to peep pixels..

[Paulus]

Wow, so much activity on this thread suddenly. Thank you for your responses.

 

To address some questions, the first highly decentered 21 SEM was definitely not within Leica tolerances. The bad (upper left) corner was so bad that you could immediately tell even on an iPhone screen without zooming in. I know this because when I showed my Leica dealer a photo of a wall with four focus stars in the corners on my iPhone he saw the one in the upper left and made a sound that can best be described as a spontaneous vomiting noise then promptly agreed that the lens was defective. Also, that bad 21 SEM was softer at any corner at 3.4 using then test than my 28 lux at 1.4, which is very different than the MTF curves indicate.

 

Perhaps it’s not so much that I’ve been unlucky with the 21 SEM but rather that I’ve been so lucky with the other lenses I’ve owned or handled, including the 21 lux, the 28 lux, the 35 lux, the 50 APO (two copies), the 90 APO, and the 135 APO, all of which were excellent by my tests out of the box.

 

All the more reason to make sure your Leica retailer or seller offers a very good return policy!

Maybe, it's an idea to make a list of lenses that deal more , than other lenses with this issue.

[MarkP]

If I start feeling sorry for myself, I can thread this thread and immediately start feeling better. I must be the most lucky person out there with such a good copy of the 21mm f3.4 Super Elmar. 

 

Me too.

[colint544]

I’m fortunate to have the retro-styled 50mm Summilux ASPH in black chrome. I’ve had it two and a half years. I use it a lot. It’s razor sharp and exquisitely made. The damping on the aperture ring is beautiful, the whole lens feels like a fine piece of engineering. A lot like my 57-year-old 35mm Summaron F2.8.

 

I also have the 35mm Summilux FLE. Had that since new in 2011. Also a very sharp lens. But out of the box, it rattled like a set of castanets, and the aperture ring spun back and forth, with almost no detents. It’s still the same, but now there’s also about two centimetres of play in the focus ring. I’ve looked after the lens, it’s never been bumped or dropped. I’m pretty disappointed in the build of the thing, especially considering the exorbitant price.

 

What I don’t get is that, clearly, Leica can still build a really top-notch, solidly engineered lens. But they seem equally capable of making something great optically, but which feels as though it’s falling apart from new. I know that hand-made items will always have a degree of variability in quality control, but my copies of the 50mm/35mm Summilux ASPH lenses feel as though one is a Leica, and the other is just some indeterminate off-brand.

[cpclee]

While I won’t dispute that you might be right, when I compare to the 50 Summilux ASPH pictures linked below my 75 AA suddenly seems perfect!

 

Point is, it’s not clear to meet when expectations will ever meet reality. Of course it’s also quite possible that there is indeed that big a range of sample variation and you are lucky to have a perfect copy.

 

http://blog.kasson.com/the-last-word/kolari-thin-stack-mod-on-a7ii-vs-m240-leica-501-4-summilux/

 

IMHO this is absolutely not normal. A lens of this qual;ity should behave well corrected and not like the pictures imply.  In comparison with my M -summiluxapsh 50.:There is no issue like this at 1,4.  I would not buy this 75mm.

 

[mdemeyer]

Make sure you note that Jim’s images are 300% enlargements. Also, he was focused on the center so field curvature is in force in the corners.

 

Not making a case one way or another, but one must always pay attention to his technical test details and not just look at the images.

[cpclee]

Yes I could tell the pictures are at least 2x enlarged just from the pixelation, and I knew from his description that the focus was set to the center of the frame.

 

FWIW, all the images I posted of my 75 AA were focused on the center as well. If I focused on each individual corner then every corner would become quite perfect and equally sharp. But that wasn’t the test I set out to do.

 

Make sure you note that Jim’s images are 300% enlargements. Also, he was focused on the center so field curvature is in force in the corners.

Not making a case one way or another, but one must always pay attention to his technical test details and not just look at the images.

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Hallo,

Look here: Leica M

[pgk]

To address some questions, the first highly decentered 21 SEM was definitely not within Leica tolerances.

 

Perhaps part of the problem is that a very small shift to 'out of tolerance' shows. So a lens which has a small knock or loosens due to a marginally slack screw or adjuster is clearly not working correctly. But this doesn't mean that it is inevitably a bad lens, just that it needs readjustment and tightening.

 

Paradoxically I have a 75mm Summilux which was way off (wouldn't focus properly at all). It was serviced and adjusted by Leica and is absolutely correct now. This lens has produced comments here on the forum because it is difficult to disassemble due to the use of adhesive. If its locked solid it can't be adjusted, insufficient tightening results in potential loosening. Seems that Leica can't win to me.