# Quality control issues with the 24-70 L II?



## heptagon (Sep 19, 2012)

These two lenses should look exactly the same:
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=787&Camera=453&Sample=0&FLI=4&API=0&LensComp=787&CameraComp=453&SampleComp=1&FLIComp=4&APIComp=0

At the short end one is better, at the long end the other. But why? They should both look best for all focal lengths and never have passed the quality control. 

Maybe the optical design has such low tolerances that Canon can't make it work properly and this was the reason for the long delays.


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## Invertalon (Sep 19, 2012)

I find one of the samples fishy to be honest. Take a look at this:

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=787&Camera=453&Sample=1&FLI=2&API=0&LensComp=787&CameraComp=453&SampleComp=1&FLIComp=2&APIComp=2

Same lens, same focal length, one a stop down from the other. The f/4 should be sharper. Why is it so soft compared to f/2.8?

Something seems off.


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## LetTheRightLensIn (Sep 19, 2012)

Invertalon said:


> I find one of the samples fishy to be honest. Take a look at this:
> 
> http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=787&Camera=453&Sample=1&FLI=2&API=0&LensComp=787&CameraComp=453&SampleComp=1&FLIComp=2&APIComp=2
> 
> ...



I have to say that I've long said that my results often don't match what TDP gets. Lens testing is really, reallly tricky. You have to be so careful and take many repeated attempts at each shot and then picking the best from that. I've done it a few times and it kinda drives you crazy. I have noticed some odd things on other lenses, like you say, where it will look like an 8 wide open and then suddenly like a 6 the next stop down and then back to an 8 the next stop and then to a 9. Doesn't make sense. Seems like bungled focusing to me.

It's also weird that every single tamron lens they test does horribly. Why? All three tamrons that I have owned have done much better.

That said, there can be copy variation.


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## Marsu42 (Sep 19, 2012)

heptagon said:


> At the short end one is better, at the long end the other. But why? They should both look best for all focal lengths and never have passed the quality control.



Maybe a good idea not to get a lens from the first batch - given the high demand and high revenue they'll probably sell every lens they've got and lower the qc standards accordingly?

Concerning tdp: The soft lens @70mm certainly shouldn't have been sold, @24mm I cannot see that much of a difference - lesson learned: paying $2000+ for a lens doesn't give you the certainty to have a perfect lens.

The same thing occurs on their 70-300L samples, I was very insecure how to manage to get a "good" copy, but the unfortunate truth is that it's near impossible to tell for a laymen w/o specialized equipment. The only thing you can do is to match the long end of the 24-70 against a known good copy of a 70-200.


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## heptagon (Sep 19, 2012)

Invertalon said:


> Something seems off.



True, there was some image misordering or something really strange about lens 2...


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## bdunbar79 (Sep 19, 2012)

Marsu42 said:


> heptagon said:
> 
> 
> > At the short end one is better, at the long end the other. But why? They should both look best for all focal lengths and never have passed the quality control.
> ...



Companies don't lower QC standards. They are written in company SOP and followed like a recipe word for word. That doesn't make any sense at all. Have you ever worked in a QC department?


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## Marsu42 (Sep 19, 2012)

bdunbar79 said:


> Companies don't lower QC standards. They are written in company SOP and followed like a recipe word for word. That doesn't make any sense at all. Have you ever worked in a QC department?



No, I did not. But I wonder how you can say with absolute determination that qc standards are never lowered no matter what the company or market situation is, nowhere, globally. That doesn't make sense to me, if I may say so. But it might very well be that my speculation is wrong and the first samples of 24-70ii will be just like the ones later on.


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## bdunbar79 (Sep 19, 2012)

Marsu42 said:


> bdunbar79 said:
> 
> 
> > Companies don't lower QC standards. They are written in company SOP and followed like a recipe word for word. That doesn't make any sense at all. Have you ever worked in a QC department?
> ...



Well, no, I can't do that. However, for a company as big as Canon, it would be unrealistic that they could take the time to purposefully lower QC standards when they are so large and handle so many manufacturing units. You'd be surprised at how robotic some of these people are doing the QC testing according to SOP. We used to joke that a monkey could do it and all you had to do was feed it peanuts every so often. No offense to QC personnel.


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## AmbientLight (Sep 19, 2012)

BDunbar is correct here. It takes many years for a manufacturer to establish good quality control procedures.

You don't change those for the worse, if there is no pressing need to do so and Canon is certainly not a company near bankruptcy, so that cost reductions in quality control may become necessary just to be able to manage cash flow.


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## kennephoto (Sep 19, 2012)

Heck I bet QC has improved since canon has been around for some time now. I know the company I work for it sure has gone up, no company wants to lose customers.


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## myocyte (Sep 19, 2012)

Quality standards are not reduced over time, but the number of units getting a major inspection off the line can decrease. In order to maintain efficient throughput in manufacturing, not all aspects of the assembly are inspected at 100%. Rather, random sampling is done at various points on the line to try and establish a confidence level in the units being built. Normally, during the first builds, Acceptable Quality Level (AQL) values tend to be stringent so that inspection sample sizes may be larger, and this is done so that the confidence level is greater for an acceptable number of units. If the inspections on those sample sizes falls within the acceptable range with an acceptable deviation from the nominal, inspection sample sizes may get smaller over time due to a reduced AQL on a well-established procedure.

I'm sure there is a standard final quality assurance procedure that is done 100% as the final step, but it is probably not as detailed as a complete inspection based on the AQL sampling of a manufacturing lot. The same also applies to the components in a lens (e.g. optic components, lens housing, etc). So, it's completely believable that there is some unit-to-unit variation since not all components are inspected at a 100% level (a lot of validation and six-sigma work is probably done in parallel to nail down the process for the manufacturing of the components too).


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## DB (Sep 19, 2012)

Deja-Vu all over again, just like the 24-70 mark 1, everyone will be talking about whether there's is a 'soft' or 'good' copy 

Having said that, according to the digital picture tests in the previous links, the 70mm @ 2.8 looks about the same as the 24mm @ 5.6

QC is all about tolerances - not every product has to be 100%, so 99% = "QC Passed"

Then there is the LensRental argument that both bodies and lenses have tolerances, so AFMA becomes an imperative...and so on


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## marekjoz (Sep 19, 2012)

Read http://www.lensrentals.com/blog/2012/09/a-peak-inside-the-canon-24-70-f2-8-mk-ii
You'll see what a big progress they've done to keep better quality in 24-70 II vs 24-70 I and where those differences you showed could come from.


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## Axilrod (Sep 19, 2012)

Could the AF have been off on the soft sample? I noticed the 24-70 II I used was backfocusing slightly.

Also, I wouldn't always trust their test results. Some of the Zeiss lenses they have on there have terrible test results but when I've used them they were absolutely amazing.


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## Invertalon (Sep 20, 2012)

Anybody know if they focus via live-view for these tests (I would hope so)? It would be weird relying on the AF of the camera, so I am 99% sure they do use live-view.


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## neuroanatomist (Sep 20, 2012)

Invertalon said:


> Anybody know if they focus via live-view for these tests (I would hope so)? It would be weird relying on the AF of the camera, so I am 99% sure they do use live-view.



From TDP:

"_Tests are conducted using externally-magnified Live View manual focusing and center-point-only autofocus. The best of the many re-focused shots (typically at least 10 sets - often 15-20) are used for the results for each camera/lens/focal-length/aperture combination. The proper lens hood is in place for all test shots, all filters are removed. Image Stabilization, if available, is turned off."_


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## LetTheRightLensIn (Sep 20, 2012)

neuroanatomist said:


> Invertalon said:
> 
> 
> > Anybody know if they focus via live-view for these tests (I would hope so)? It would be weird relying on the AF of the camera, so I am 99% sure they do use live-view.
> ...



Keep in note:

1. they did not do that on their earlier tests, they were much less careful earlier on
2. despite the above they still get weird things some apertures suddenly going to junk, maybe it's just mixed up files now and then, but for some reason they seem to only ever get bad copies of tamron


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## kaihp (Sep 20, 2012)

myocyte said:


> Quality standards are not reduced over time, but the number of units getting a major inspection off the line can decrease. In order to maintain efficient throughput in manufacturing, not all aspects of the assembly are inspected at 100%.


While statistical testing is the norm in many companies (and the only thing making sense in many cases), the QC procedure do depend on the type of business you're in. I work for a medical device company, and we do 100% inspection (all units are tested). Most electronic products like mobile phones are 100% tested as well.


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## heptagon (Sep 21, 2012)

For the price of L-Lenses, Canon should do 100% testing. Especially early in the production.

TDP usually does a pretty good job in testing lenses so i guess that the second lens really shouldn't have been sold.


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## serendipidy (Sep 21, 2012)

+1000!!

Why should it be a lottery to get a decent quality lens from Canon? Those with experience maybe can detect the less than ideal copies and send them back. The casual hobbiest may not and just be stuck thinking that's the best they can do. Also, when someone sends several less than razor sharp new copies back, to say B&H or Adorama, until they find one they like, what happens to those returned copies? Are they sent back to Canon or resold?


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## Viggo (Sep 21, 2012)

You'll see MUCH bigger variation out in the field when you're using phase-AF, and even then you'll probably hardly ever notice it in a real shooting situation.

Besides, apertures can vary alot, and there is VERY few lenses that follow the "soft open, better one stop, very good two stop down and diffraction softens at f22"- curve. For example the 50 L is sharper at 1,8 than at 2,2. 

And the 24-70 mk2 is no different and it still is the best zoom ever, but it's when a test charts shows you a slight difference it's a bad copy and it sucks and Canon should burn in hell.

I like my lenses to be optimized as well, and I have had several copies of every lens (never saw a difference) and I adjust them with AFMA, now lately, with the best method, FoCal. They are adjusted as good as they can be on the best AF-body ever made, and that's good enough for me. 

Perfect phase-AF is a myth.

http://www.lensrentals.com/blog/2012/07/autofocus-reality-part-1-center-point-single-shot-accuracy


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## heptagon (Sep 21, 2012)

@Viggo: Yes, Phase-AF is a big problem. But Lensrentals found out that New Cameras with New Lenses can have a very good phase-AF. (Look for part 2 or 3 of the story)

However, what the test of the two lens samples shows are much bigger variations. Other manufacturers are even worse than that. Maybe Tamron gets tested 3 times and the worst is used while for canon it's the best sample.

For the new lenses it gets harder and harder to achieve near-perfect manufacturing because the tolerances required to achieve the high quality results get lower and lower. This is not an easy problem to overcome. Lensrentals are the only site which sometimes tests a number lenses from one batch. They could provide some numbers on the rate of bad lenses per model. Other sites which only test a few samples cannot provide conclusive evidence on how high the rate of bad lenses is.


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## Studio1930 (Sep 21, 2012)

Samples 1 and 2 are very close when you look at the 24mm shots. This is the exact reason the newer camera bodies have AFMA for both near and far on zoom. 

Also some good reading here...

http://www.lensrentals.com/blog/2011/10/the-limits-of-variation


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## Mt Spokane Photography (Sep 21, 2012)

Unfortunately, lenses can be damaged during handling and shipping, and can, of course, be improperly assembled.
QC inspection went away years ago for most Japanese companies, its a obsolete process. It was replaced by Total Quality Management which goes far beyond just inspecting finished products like they did 20 years ago.


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