Lensrentals tear down Canon RF 100-500mm

AlanF

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A very impressive tear down of a very impressively designed and constructed lens. A driving motive was to discover why they had 4 copies with a cracked element, which Roger originally thought to be part of the unparked IS unit but later reported to be physically compartmentalised from it. This detailed description is worth reading to see just how much care, thought and attention Canon has brought to the design of this lens. The punch line of why the element cracked is...
 

usern4cr

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Sep 2, 2018
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A very impressive tear down of a very impressively designed and constructed lens. A driving motive was to discover why they had 4 copies with a cracked element, which Roger originally thought to be part of the unparked IS unit but later reported to be physically compartmentalised from it. This detailed description is worth reading to see just how much care, thought and attention Canon has brought to the design of this lens. The punch line of why the element cracked is...
Wow! That's an amazingly detailed teardown of the RF 100-500 f4.5-7.1L lens! It's hard to imagine someone being able to teardown a lens like this, and even harder to imagine them putting it back together! I'm glad they were so impressed at the build quality, and didn't seem to be concerned about the IS unit movement we have all been wondering about.

So I guess everyone can have a big exhale, smile, and get their own copy of this lens - it's still my favorite RF lens so far! :)
 

Joules

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Great read, thanks for sharing. Also a nice ending, showing why it is beneficial to raise awareness and discuss certain product aspects:

"In any case, we’ve forwarded all of our data and broken lenses to Canon. Canon is always proactive about investigating these things and one of the few companies willing to publicly say when they actually have a problem. They have assigned a team to look into it, we’ve already given them some more information they’ve requested, and they’ll figure out if there’s a problem or not."

These days there is a lot of blame being thrown around for companies releasing 'unfinished' products and treating customers as 'beta testers'. But with the complexity and constraints (time, cost, covid, ...) of modern products, there is only so much that can be rigorously tested by the companies before they have to rely on testing and feedback from the far more divers conditions customers encounter for further improvement.
 

YuengLinger

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Yes, Yuenglinger was right to bring it up and it's credit to them that they changed their minds when the facts changed, which I am afraid to say is not a universal trait.
Fortunately I married an analytical, patient, easy-going woman who read the teardown article and said, "Go ahead. Get it again. It kept you out of the house when you had it for a couple weeks." :D
 

zim

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That was a great read, also love the humour top marks for the Hardy boys ref.
Even though it's about a broken element it's a fantastic advert for Canon design and engineering.
 

YuengLinger

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That was a great read, also love the humour top marks for the Hardy boys ref.
Even though it's about a broken element it's a fantastic advert for Canon design and engineering.
When I was a kid, I thought the Hardy Boys book covers were way better than the books themselves. (Every boy I knew had a boxed set--and the girls had Nancy Drew.) But I was more interested in science fiction and Tarzan. And I didn't know any boys who talked the way characters in the books did. I ran with a pretty salty bunch, I guess.

But Roger's use of the cover was masterful! Added much needed levity.
 
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zim

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When I was a kid, I thought the Hardy Boys book covers were way better than the books themselves. (Every boy I knew had a boxed set--and the girls had Nancy Drew.) But I was more interested in science fiction and Tarzan. And I didn't know any boys who talked the way characters in the books did. I ran with a pretty salty bunch, I guess.

But Roger's use of the cover was masterful! Added much needed levity.
Indeed. Although have to admit my favourite was The Three Investigators :unsure::geek::sneaky:
 

YuengLinger

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Indeed. Although have to admit my favourite was The Three Investigators :unsure::geek::sneaky:
I did like Alfred Hitchcock. I remember reading this on a snowy weekend when I was eight:
1611417832723.png


One question I do have about the cracked element, though: If Canon didn't know anything about it cracking, how was it limited to an early production run? One guess I have is that the problem was actually confined to a tiny number of these elements--without Canon needing to intervene. But, no matter, I already ordered from Amazon, the only authorized merchant I've seen to have it in stock for most of the past month. I can always decide about the CarePak Plus after I've inspected and tested the new one.
 
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Joules

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If Canon didn't know anything about it cracking, how was it limited to an early production run?
Just as we are used to sample variations between individual items if a product line, there are variations in the overall production process unless it is fully automated from source material to finished good and all of the facilities, tools, processes and conditions are fully optimized before mass production begins.

Especially under the varying workplace conditions caused by the pandemic and a production start in general, it would not surprise me if a single batch got out of spec for a reason that was only present temporarily as part of these changing conditions. Either it wasn't noticed or not thought to cause a problem significant enough to warrant a recall.

If you follow SpaceX development or just happened to pay attention to the launch of the Crew 1 mission (first US provided launch of humans to the ISS since the shuttle ended), you may have heard that a similar thing happened there. Even with the attention to detail in the rocket sector, a detail was missed. There was a variation in the effectiveness of a cleaning step performed by a subcontractor. On certain rocket engines, residue of the manufacturing process was not cleaned entirely, leading to blocked channels that affected engine startup reliability. Here's a nice quote from one of the guys looking into the matter, which illustrates my point:

“There’s certainly the possibility that we had cases of this earlier, and they were basically so harmless that we completely missed them,” Koenigsmann said. “It’s also possible that little things changed. This is a process that’s done out of house at a special vendor, so it could be that person is now more generous with cleaning fluids or other things.”

From: https://spaceflightnow.com/2020/10/...-blocked-valve-ahead-of-november-crew-launch/
 
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YuengLinger

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Just as we are used to sample variations between individual items if a product line, there are variations in the overall production process unless it is fully automated from source material to finished good and all of the facilities, tools, processes and conditions are fully optimized before mass production begins.

Especially under the varying workplace conditions caused by the pandemic and a production start in general, it would not surprise me if a single batch got out of spec for a reason that was only present temporarily as part of these changing conditions. Either it wasn't noticed or not thought to cause a problem significant enough to warrant a recall.

If you follow SpaceX development or just happened to pay attention to the launch of the Crew 1 mission (first US provided launch of humans to the ISS since the shuttle ended), you may have heard that a similar thing happened there. Even with the attention to detail in the rocket sector, a detail was missed. There was a variation in the effectiveness of a cleaning step performed by a subcontractor. On certain rocket engines, residue of the manufacturing process was not cleaned entirely, leading to blocked channels that affected engine startup reliability. Here's a nice quote from one of the guys looking into the matter, which illustrates my point:

“There’s certainly the possibility that we had cases of this earlier, and they were basically so harmless that we completely missed them,” Koenigsmann said. “It’s also possible that little things changed. This is a process that’s done out of house at a special vendor, so it could be that person is now more generous with cleaning fluids or other things.”

From: https://spaceflightnow.com/2020/10/...-blocked-valve-ahead-of-november-crew-launch/
And then there is the size of Canon, Inc., making it very difficult for everybody to be informed simultaneously of any issue. You might remember the key reason I returned the 100-500mm while in the refund window was because Canon CPS in Virginia believed my copy to be faulty, to not be parking because of a defect. And now we know that was conjecture based on past experience, not up to date understanding.

So maybe a few QC techs way up the optics production stream caught it?

Bottom line, for this customer, it is not a concern. I want to believe the cracking of the element was isolated, as Roger believes. As expensive as the lens is, compared to riding atop a rocket, or flying in a Boeing 737 MAX, a slight chance of an element failing is a reasonable risk for me.
 

koenkooi

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Fortunately I married an analytical, patient, easy-going woman who read the teardown article and said, "Go ahead. Get it again. It kept you out of the house when you had it for a couple weeks." :D

My favourite photo store called last week to say they are getting a batch of R5s in that will go into stock instead of backorder and asked if I wanted another one. I said "No, one is enough for me" and raved a bit about how nice the 100-500 is on the R5. The salesperson replied with "You're lucky you have one, it will be hard to get one the next few months here in Europe, we just got off a call with Canon Europe about the supply situation. If you want more R5s, that won't be a problem."

I don't know how that situation translates to your region, but get that order in quickly :)
 
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tron

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They mentioned that all their failures appear to come from around the same batch. Did they clarify what batch that was?
They haven't but of course it is not 100% certain that only one batch is involved. Even so knowing the serial numbers would bring us some peace of mind.

I think I will get it from Amazon.de sometime in the future. Right now it is not available for delivery so the next available item will most certainly come from a new batch.

Or I could try to get it locally from one dealer that right now does not have it in stock. I am in no hurry for this.
 
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