Lens quality control

Started Sep 24, 2013 | Discussions thread
parallaxproblem Veteran Member • Posts: 5,335
Re: Sample variation is not that big a deal

ProfHankD wrote:

parallaxproblem wrote:

Howver I think there is another factor at play here: offshoring ... Take a product that has been built in an established factory with a history of high-quality production and a workforce that takes pride in its activity, and move it to a developing nation where you recruit from scratch the cheapest workforce possible (why move if it isn't to pay the least salaries possible?) and the quality of output will simply *not* be the same whatever processes you put in place.

I'm not scared by this practice -- because when it doesn't work, which I believe is the norm,

I'm very glad to see somebody in academia accepting this. The compliance (and in a few cases complicity - mentioning no names, like HBS) of some sections of academia in the more absurd aspects of contemporary business and finance behaviour is really quite disgraceful

it is almost always quickly stopped. I've seen a lot of companies (including a local biggie: Lexmark) send all sorts of engineering and production work to other countries in search of cheaper labor, but most of them have quietly pulled the operations back after a year or two.

I've heard of this happening in other sectors but I'm not sure this happens with lenses - Pentax had a disastrous time with their outsourcing to Vietnam: they closed their japanese plant and their japanese-built lenses basically 'ran out' (even 'ordinary' 50 and 35mm lenses) whilst production issues with their Vietnamese plant meant there were no replacements or proper volumes of stock in the supply chain for several years (second-hand Japanese-built lenses were being sold on Ebay for much more than new price because it was impossible to source them new, and stock arriving in B&H was being sold-out within hours!). Alll of which coincided with the DSLR boom years and basically cost Pentax the chance to get proper penetration into the DSLR market and then followed the three subsequent buyouts and takeovers of Pentax ending with it being absorbed into Ricoh. However even now there is no suggestion that production will be moved back to Japan

The truth is that there's no free lunch. It costs a lot to develop the physical and personnel infrastructure in places where labor is cheap... usually enough to reverse any cost advantage. By definition, large, successful, companies don't get to make and continue mistakes that kill product quality for very long.

That said, things change as investments are made. When I was a kid, I remember my parents regularly sending aid money to help starving kids in South Korea. Well, South Korea isn't so poor now and some of the highest-quality high-tech stuff comes from that country -- especially things like LCD panels and DRAM memory parts. I've bought lots of camera parts (e.g., lens adapters) made in China and, to put it bluntly, they haven't been inferior to similar parts coming from Japan or Europe. Somebody has obviously invested a lot of money in China....

It's amusing - I have a Theta CD player which I bought in the late 1990's and which the box specifically prohibits from being exported to a number of countries, including China (and Vietnam and North Korea), because of the level of technology employed in the digital filtering in the DAC circuitry! I doubt the modern equivalent is produced anywhere other than in China

There's no doubt that in some years time the offshored factories and their working cultures will be 'mature' and the quality of products coming out of them will be of a similar level to that produced by the original factory. However by that point local wages will probably have risen to a level that makes the whole exercise even more pointless

I do believe that there is a new threat to quality control: less testing of complete systems made of outsourced parts. Standard engineering practice (SEP) is that tolerances needed for components to function properly are determined and specified as part of the design process -- especially for things like lenses. Unfortunately, the underlying analysis is usually based on most components being clumped around their ideal values, which is often no longer a valid assumption. It is now common that the companies making the parts often don't even know what the ideal value is, but just the range of acceptable values (incidentally, the ideal value often isn't in the center of that range). The concept of tooling being designed to "wear through" a tolerance range over a long production run also causes problems. Thorough testing of the final product would quickly reveal when too many parts being too close to the wrong edges of their tolerance ranges has resulted in a poor product, but such testing is expensive and unfortunate combinations of in-tolerance parts should be rare, so it is often apparently more economical to do minimal (if any) testing and let consumers discover and return the out-of-spec products.

There is also the problem of deliberate fraud in the supply chain. The capacitor scandal of a few years ago is well known - where there were many failures of consumer goods caused by the substitution of inferior quality capacitors for the correct item by some suppliers

What is less well appreciated is how difficult it is for suppliers to verify the actual origin of certain devices and how frequently parts which have failed testing are not scrapped but quietly put aside by 'entrepreneurial' employees and then later re-interted into the supply chain at whatever point they have a personal 'contact'. It even seems that there might have been a few 'unauthorised' production runs of some chips in factories during 'downtime'. Obviously these chips were not subject to any appropriate form of QC, but still ended-up in the supply chain (another 'unforseen' cost of offshoring)

There have been some fascinating (and frightening) investigations into memory chips and memory cards, expecially interesting is the role played by Kingston as a 'memory broker' used by both real memory manufactures (Sandisk and Toshiba) as a 'buffer' when they produce too many of a certain type of memory card!

My advice: test the product yourself and return it ASAP if it is clearly out of spec. I'm not talking about normal minor variations that produced products within the engineering specs -- I'm talking about the relatively rare clear outliers, like that article from LensRentals talked about.... It doesn't take sophisticated testing to identify outliers, and companies are usually good about repair/replace of them. For example, Sigma has had an unfortunate history of having a lot of outliers,

It seems that they've upped their game recently... thankfully!

but they also have usually been quick to make good on such returns.

The US retailers have a good returns policy but it's not so easy with Sony in Europe... I sent my SEL16/2.8 back to Sony with a decentering problem. Sony acknowleged the issue but refused to replace/repair the lens as they said 'it was less decentered than our reference copy'!!!!!!!

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