ramarren Posted February 17, 2016 Share #1 Posted February 17, 2016 Advertisement (gone after registration) I thought this an interesting look inside the SL lens... https://www.lensrentals.com/blog/2016/02/a-peak-inside-the-leica-vario-elmarit-sl-24-90mm-f2-8-4-asph I wasn't too thrilled with the implied snark/disparagement of Leica/Leica users in his first paragraph, but didn't let it detract from the nice glimpse inside the SL lens. It seems a nicely designed, solidly constructed piece that will last a long time. Link to post Share on other sites More sharing options...
Advertisement Posted February 17, 2016 Posted February 17, 2016 Hi ramarren, Take a look here Vario-Elmarit-SL 24-90mm disassembly by Roger C @ LensRentals. I'm sure you'll find what you were looking for!
Jeff S Posted February 18, 2016 Share #2 Posted February 18, 2016 Well, he gushed over the construction, engineering and sealing of this Canon lens... https://www.lensrentals.com/blog/2015/02/canon-100-400-is-l-mk-ii-teardown-best-built-lens-ever I'm curious if he held back on compliments here due to either: the cost differential and related expectations ($5000 vs $2000); or that he didn't really take it fully apart like the Canon; or that he's dealing with tele vs mid-range zooms; or that he was just less impressed. Jeff Link to post Share on other sites More sharing options...
ramarren Posted February 18, 2016 Author Share #3 Posted February 18, 2016 Roger C sent me a note on DPR, apologizing for the comments. He was forthright and candid about it. In truth, he seems to have liked the SL lens quite a lot. Link to post Share on other sites More sharing options...
LocalHero1953 Posted February 18, 2016 Share #4 Posted February 18, 2016 I don't see much problem with his remarks in the first para. They're factually correct - Leica is not synonymous with technological innovation to the general photographic public, and most of them don't notice Leica's products, except the price. We may not agree with them, but they're much more interested in Canikon, Sony, Olympus and Fuji, and buying their products and the electronic features they develop before Leica. Leica's advances in lens quality and camera usability are just not things that catch the public eye. An interesting article, and I'm glad someone is heroic enough to take apart a lens of this price. Now if he'd only open a branch in the UK, we'd get a chance to do all that trying by hiring before buying that is such a regular recommendation from US members of LUF. Link to post Share on other sites More sharing options...
wlaidlaw Posted February 18, 2016 Share #5 Posted February 18, 2016 Given German labour costs, the 24-90 looks quite cheap now. As someone who originally trained as a materials scientist engineer, I am delighted to see the trouble Leica has taken with robust fixings, bushings etc, pretty much all in metal. A friend and I took apart a mid range Nikon full frame zoom lens that had been dropped from some height and was declared "beyond economic repair". We were surprised how much plastic there was on moving parts and in bushings. It looked like a mixture of parts made from polypropylene, nylon or high density polyethylene. Sigma I understand, even press their aspheric elements out of transparent plastic with a glass core. As long as the electronics don't give up (a big if), I can see this 24-90 lens being heavily usable over a long period. Link to post Share on other sites More sharing options...
jrp Posted February 18, 2016 Share #6 Posted February 18, 2016 For a non-material scientist or weight lifter, what is wrong with plastics and other advanced materials? Link to post Share on other sites More sharing options...
ramarren Posted February 18, 2016 Author Share #7 Posted February 18, 2016 Advertisement (gone after registration) I'm not a materials scientist. There's nothing particularly wrong with plastics and other composite materials when the materials are applied to applications properly, but they tend not to be as durable or dimensionally stable as metals over long stretches of time. Lenses are long term purchases, particularly high-end lenses like this one, so it's good to see robust, durable materials used throughout its construction. I have no issues with the electronics. From the looks of it, they've used good quality bits and have insulated them properly from the body of the lens with shock mounting. I have other electronics that date back twenty, thirty years and are still 100% reliable, and they are not as robustly constructed as these from the look of them. The one piece of the lens internals that I would wager would be the first to need service or replacement is the focus servo motor, but even that is in a well designed, dust- and weather- sealed, low-stress environment. All in all, this lens looks to be a solid, well-constructed piece. The fact that Roger could take it apart and put it back together with no issues is another signal point in its favor; there are some similar lenses on the market that can only be dismantled and reassembled with very special equipment, making them effectively unserviceable in the long term. Link to post Share on other sites More sharing options...
wlaidlaw Posted February 18, 2016 Share #8 Posted February 18, 2016 For a non-material scientist or weight lifter, what is wrong with plastics and other advanced materials? The main problem is deterioration over time, from oxidation, depolymerisation, ultra violet degradation, reaction with lubricants and so on. In that most modern plastics have only been around for less than 50 to 60 years, there is not a great deal of data on long term deterioration. I have very personal experience of this. In 2003 I had a total ankle replacement with a joint called a Merck AES joint. The plastic bearing material between the two titanium plated cobalt chromium metal components in my leg and foot, deteriorated, softened and distorted over 9 years, to the extent that it made the metal bits come loose in the bone and the T shaped bit in my leg, ended up fracturing at the base of the T. Nobody in the UK would agree to work on it, so I had to go to Switzerland to have a replacement joint fitted after a lot of bone grafts. The materials science of metals is a whole lot more developed than plastics. Link to post Share on other sites More sharing options...
Jeff S Posted February 18, 2016 Share #9 Posted February 18, 2016 Mr. McGuire: I want to say one word to you. Just one word. Benjamin: Yes, sir.Mr. McGuire: Are you listening?Benjamin: Yes, I am.Mr. McGuire: Plastics. Jeff Link to post Share on other sites More sharing options...
farnz Posted February 19, 2016 Share #10 Posted February 19, 2016 The main problem is deterioration over time, from oxidation, depolymerisation, ultra violet degradation, reaction with lubricants and so on. ... There's Environmental Stress Cracking too. Polymers are excellent at a great many things but load-bearing tends to produce a short service life in polymers compared with metal or ceramic equivalents. Pete. Link to post Share on other sites More sharing options...
wlaidlaw Posted February 19, 2016 Share #11 Posted February 19, 2016 There's Environmental Stress Cracking too. Polymers are excellent at a great many things but load-bearing tends to produce a short service life in polymers compared with metal or ceramic equivalents. Pete. About 9 years from my experience Wilson Link to post Share on other sites More sharing options...
jmahto Posted February 20, 2016 Share #12 Posted February 20, 2016 He doesn't mention (or doesn't know) what kind of metal Leica uses. For this price I want a lightweight exotic material. Link to post Share on other sites More sharing options...
FlashGordonPhotography Posted February 20, 2016 Share #13 Posted February 20, 2016 He doesn't mention (or doesn't know) what kind of metal Leica uses. For this price I want a lightweight exotic material. Leica lenses are made, almost entirely of unobtanium. Gordon Link to post Share on other sites More sharing options...
wlaidlaw Posted February 21, 2016 Share #14 Posted February 21, 2016 More seriously, many exotic materials, such as titanium or beryllium/aluminium alloys have poor natural lubrication qualities when used as bushes or in direct exotic material to material moving contact situations. This lead to some serious problems on racing cars, where about 25 years ago, 100% titanium spherical ("Rose") joints came out. In high load situations, the failure and wear rate was wholly unacceptable, because the sliding parts of the joint suffered what is called spalling, which is the metals tearing each other up. Titanium is still used for the outer housings of these joints, but the inners are usually now a stainless steel. Brass and bronze are very old materials, dating back around three thousand years plus. However their crystalline structure leaves them with marvellous self lubricating properties, still very useful today. This is only surpassed by specialist materials such as oilite (a sintered porous bronze, then saturated with oil, graphite or grease) or surprisingly, the wood lignum vitae. Wilson Link to post Share on other sites More sharing options...
ramarren Posted February 21, 2016 Author Share #15 Posted February 21, 2016 You motivated me to look up lignum vitae, Wilson. Fascinating stuff! Seems to be a big benefit over other bearing materials in the hydroelectric industry and used also in the propellor shafts of many ships and submarines during WWI and WWII. Thanks! Link to post Share on other sites More sharing options...
LocalHero1953 Posted February 21, 2016 Share #16 Posted February 21, 2016 I have various pieces of lignum vitae lying around - liberated from Harland & Wolf shipyard in Belfast by an uncle who used to work at Shorts next door. They are left over from marine bearings - though probably not in latter years, which is why no one missed them when the stock found another home. It is utterly unusable by an amateur woodworker like me - far too hard for my tools. Perhaps if I was a sculptor.... Link to post Share on other sites More sharing options...
wlaidlaw Posted February 21, 2016 Share #17 Posted February 21, 2016 I have various pieces of lignum vitae lying around - liberated from Harland & Wolf shipyard in Belfast by an uncle who used to work at Shorts next door. They are left over from marine bearings - though probably not in latter years, which is why no one missed them when the stock found another home. It is utterly unusable by an amateur woodworker like me - far too hard for my tools. Perhaps if I was a sculptor.... Paul, Even quite small pieces are saleable. People use them in restoring old clocks and making model boats etc. Wilson Link to post Share on other sites More sharing options...
stevieg Posted February 21, 2016 Share #18 Posted February 21, 2016 The main problem is deterioration over time, from oxidation, depolymerisation, ultra violet degradation, reaction with lubricants and so on. In that most modern plastics have only been around for less than 50 to 60 years, there is not a great deal of data on long term deterioration. I have very personal experience of this. In 2003 I had a total ankle replacement with a joint called a Merck AES joint. The plastic bearing material between the two titanium plated cobalt chromium metal components in my leg and foot, deteriorated, softened and distorted over 9 years, to the extent that it made the metal bits come loose in the bone and the T shaped bit in my leg, ended up fracturing at the base of the T. Nobody in the UK would agree to work on it, so I had to go to Switzerland to have a replacement joint fitted after a lot of bone grafts. The materials science of metals is a whole lot more developed than plastics. Slightly off topic, but 9yrs for a total ankle replacement isn't too bad. They aren't as good/developed as hip/knee replacements. We usually look to 10-15yrs for a good innings! Highly cross-linked polyethylene spacers are making them last a bit longer, but multiple thousands of daily sheer stresses when one walks, coupled with 70kg+ mass going through approx 5cm squared surface area will eventually take its toll! I guess we should be glad we don't have to walk on our M's! (Surprised no one here in the uk took your case on though. I presume that going to Switzerland you went to see Dr Ripstein, who co-designed the De Puy Mobility. (My favoured prosthesis, until De Puy took it off the market recently due to not selling enough in the USA, I think!!) Link to post Share on other sites More sharing options...
scott kirkpatrick Posted February 22, 2016 Share #19 Posted February 22, 2016 Slightly off topic, but 9yrs for a total ankle replacement isn't too bad. They aren't as good/developed as hip/knee replacements. We usually look to 10-15yrs for a good innings! Highly cross-linked polyethylene spacers are making them last a bit longer, but multiple thousands of daily sheer stresses when one walks, coupled with 70kg+ mass going through approx 5cm squared surface area will eventually take its toll! I guess we should be glad we don't have to walk on our M's! (Surprised no one here in the uk took your case on though. I presume that going to Switzerland you went to see Dr Ripstein, who co-designed the De Puy Mobility. (My favoured prosthesis, until De Puy took it off the market recently due to not selling enough in the USA, I think!!) Further off topic -- are you a satisfied user of one of these or an installer? scott Link to post Share on other sites More sharing options...
wlaidlaw Posted February 22, 2016 Share #20 Posted February 22, 2016 I sent a PM to Steveig. I did not have the replacement he mentions but a different prosthesis, which is specifically designed as a revision replacement for the failed AES joint, and takes into account, the massive bone erosion and cobalt necrosis caused by the failing AES joint (the titanium plating which is the bonding and isolation layer between the structural but toxic cobalt/chromium metal inserts and the hydroxyapatite cementless coating, which bonds to the original bone, failed and peeled off). The prosthesis I had, was designed by the professor of surgery at Basel University, Prof. Beat Hintermann, who did the operation on me. It turned out to be a lot more complicated than originally planned, due to the fracture of the top metal component, which then left the stem of the "T" in my tibia when the base was taken out, and it had to be removed. The bone necrosis was also a lot worse than the scan showed, which meant they had to send out to the bone bank (about an hour away from the hospital) for additional graft material. I had the operation done in the Liestal Hospital near Basel. Even though it is quite near the French border, nobody spoke French, in which I am reasonably fluent. I quickly had to remember my German from nearly 50 years before, when I had a year in Switzerland on a university exchange scheme. The new prosthesis is more satisfactory and comfortable than the AES one ever was. Wilson Link to post Share on other sites More sharing options...
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