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Author Topic: Canon L lenses and quality control  (Read 19523 times)
Ray
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« Reply #40 on: April 23, 2006, 12:12:11 PM »
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And how do you come up with a $50 per lens number? I would be interested in how much you would think developing and implimenting a robotic MTF line would cost? Not forgetting that the data needs to be printed and packaged with the lens. You also need to know than a $50 increase in manufacturing, does not translate into a $50 increase in product price.


Anon,
Of course I don't know precisely that $50 is a realistic price. I'm using my experience of cheap, but high quality, products coming out of China. The production cost is very significantly lower. You must be aware this is a huge problem for the USA, causing a massive  trade imbalance. The solution might be that China raises its currency exchange rate, but regardless of such moves there's a global trend to cut costs by moving offshore, which is perfectly legitimate because it offers underdeveloped countries the opportunity to develop,

By way of analogy, I should mention that I'm seriously considering retiring in Thailand because, on average, I calculate the cost of living there is 1/6th of what it is in Australia.

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Currently, manufacturers sample products in a production run with MTF curves. Why change that system which on the whole works well.


My understanding is that sampling of productions runs applies to just the occasional lens in the batch. Whatever the procedure is, there appears to be room for improvement.

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Since very few understand how these numbers translate into images, people are going to force the manufaturers to produce at the level of the best lenses


That's a good trend.

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which translates into higher prices or manufacturers dropping lenses and maybe going out of business


This is the free market. If the kitchen's too hot then leave. You are not batting for a subsidy for the Mamiya ZD, are you?

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Image quality is subjective. The MTF does not indicate a lens will make good images, but simply its response to spacial frequency. Manufacturers still take images with the lens at the end of the day to make sure the lens works. MTF is more of a guide to what is wrong, rather than what is right.


Image quality might well be subjective, but MTF is not. It doesn't cover every aspect of lens performance, but it's the best single guide we have. I don't agree that it's more of a guide to what's wrong. It's simply a guide, and it's very objective.

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Also your logic is a little strange. You think the owner is actually gettting bad images, but he does not know it? Can't he just look at his pictures and see? Or are you saying that even if someone is happy with the lens they have, they should be careful because there could be one better?


No. We're dealing in shades of gray. Something is good in relation to something not so good. I might be biased because my father was an amateur photographer and I was exposed to these issues at an early age. I remember vividly as a youngster, before automatic focussing and exposure was invented, how proud  some people would be of their incorrectly exposed, out-of focus and ridiculously composed images.

The whole of Europe has basically rejected High Definition TV because it was thought (through market research, no doubt) that people don't care enough. We have it in America and Australia, and I'm proud of that.

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Optics is one area of consumer goods were you get what you pay for. This is why some seemingly similar products are different prices. Not all 50mm lenses are the same and the price reflects that. Sure, sometimes there is a lemon, and sometimes the designers goof, but on the whole, the quality of the products are reflected in the price and the chances are you will buy a good sample.


No, wrong. Optics is an area which is rather esoteric and the consumer, in the absense of real information, buys at a price expecting the quality will be commensurate with that price. We on Luminous Landscape know that these expectations are not always met. There's something lacking in the QC chain, hence the reason for this thread.

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FYI, returns and defective products cut into profits. Manufacturers understand this more than most consumers realize. And since margins in this business are very tight, there is little room to have products returned. It is far more cost effective to build a good product than a bad one.


I agree in principle that this is the case, but is it not also the case that Canon has an interest in not informing the customer of the precise tolerances of a particular lens in order to fudge the issue. If I'm not satisfied with a particular lens, perhaps after the return period has expired, and I send it back to Canon for calibration and I'm still not satisfied, and Canon say, 'Sorry! The lens is within tolerance". What can I do? I can't argue because I don't know what the tolerance is.

This entire issue is fundamentally about transparency. (In more ways than one. Pun intended.)
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Mark D Segal
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« Reply #41 on: April 23, 2006, 01:06:20 PM »
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I just clicked into Photodo's website, went to the Canon lenses link and discovered that it was last up-dated in June 2000. Fine, when people do such things for the love of it no one should complain. It is a whole different story if a manufacturer must develop such systems, maintain them, and then maintain the infrastructure for dealing with the consumer "dialogues" that ensue.

I agree that transparency is the issue, and QC is also the issue. The evidence on this website is for sure anecdotal - we don't really know what proportion of "L" lenses or high-grade Nikon lenses sold in a year disappoint their customers (we can't say they are sub-standard because we don't know what the standards are). But we do know there are dissatisfied customers who, if they act on time, get their problems rectified, which means there were issues to rectify. So one doesn't need to get too academic to know that there is room for improved QC and more transparent quality standards at the high end. I think the furthest it would be practical for any manufacturer to push this would be a single minimum standard they meet every time for the high-end production.

If you watched Volume 14 of LLVJ you would see that in Denmark at Phase-I every back is rigorously tested before it leaves the plant. Well, it is a small scale operation selling stuff in the USD 25K range - so that's it - for production runs the size of Canon's - even if only for the high-end stuff, they would need some very practical methods for improving on their present level of QC if they are to keep prices in the range we are accustomed to.

I think this thread has pretty much raked-over these issues as far as we can take them - time for a holiday in Thailand, Ray - wish it weren't 21 hours of flying and thousands of bucks away from here.  
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
Ray
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« Reply #42 on: April 25, 2006, 12:28:21 AM »
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May I say Mark, I think you'd make an excellent moderator   .
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Mark D Segal
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« Reply #43 on: April 25, 2006, 07:40:19 AM »
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Thanks for the compliment Ray. What's fun here is trying to see one's way through the issues - I think we all learn from each other in the process.  
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
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