Luminous Landscape Forum

Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: StephenEdgar on April 09, 2006, 06:22:26 am

Title: Canon L lenses and quality control
Post by: StephenEdgar on April 09, 2006, 06:22:26 am
Hi Folks,
I'd like to buy a  Canon 24-85 f4 L-series lens and I've being doing as much research as I can to ensure I understand the optical strengths and weaknesses of this lens. However, I've been suprised, (after visiting numerous forums), at the number of these lenses that seem to be returned because the purchasers had (apparently) got a 'poor' example of the lens. Am I seeing a 'biased sample' or is purchasing any lens more hit and miss than I ever realised? I'm not a 'pixel peeper' and certainly don't want to start 'testing' a new lens to ensure I've got a 'good' example.
Any comments or insight would be appreciated
Regards
Stephen
Title: Canon L lenses and quality control
Post by: StephenEdgar on April 09, 2006, 06:27:54 am
Oops, sorry I meant to refer to the Canon 24-105 f4 L lens. Sorry for any confusion
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 09, 2006, 09:44:28 am
Stephen, there is sample variance. When spending so much money on a lens it is best to buy it from a dealer who will allow you to exchange it within a short time period if you are not satisfied with the sample you buy.

I own one of these lenses - this website published a test comparison I did between the 24~105L and the 28~135 IS (http://www.luminous-landscape.com/reviews/lenses/24vs28.shtml). The lens I tested was a sample from the original batch. Canon recalled all those lenses because they said there was excessive flare (which I never noticed as being excessive). The lens they gave me in exchange was less crisp than the "defective" one I returned. So, much to Canon's surprise, I promptly retrieved my "defective" lens and I have been extremely pleased with it ever since.

I don't do formal tests with resolution line charts. I'm only interested in what real-word photographs will look like as a print. There is a brick community center protected by link-fencing up the street from where I live. The sun hits it at different angles as the day progresses and it provides all the detail, texture and contrast I need to judge whether a lens is satisfactory. I do a matrix of shots at wide, 50mm and telephoto at wide-open, mid-range and f/11 f-stops.

The most challenging performance test for these zoom lenses is wide angle at wide aperture. That is where they are at their weakest. But since only a small proportion of your photos are likely to be made with those settings, it is best to judge performance accross the matrix.

Of course, testing this way you will never know whether you have the BEST this lens can deliver (you would need to test many lenses under identical conditions to judge that), but at least you will know whether the image quality is satisfactory relative to your expectations.

A note about post-processing. There are two schools of thought. One is to judge the RAW files with no sharpening to see what the lens does unaided - but biased by the influence of the sensor's anti-aliasing filter. The other is to sharpen the RAW file as you would normally, because this is how you will use the product. I think both approaches tell you something, but the latter is the bottom line.
Title: Canon L lenses and quality control
Post by: Gary Ferguson on April 09, 2006, 01:18:49 pm
I've never had an optical quality problem with any of the thirty or so Zeiss or Leica lenses that I've bought new over the years. With every other brand I reckon on returning about one in three because of faults. Canon L lenses are no different, including a breathtakingly expensive 500 4.0L IS that had an obvious decentering error, and multiple exchanges of a 20mm plus hood until Canon could provide one where the hood fitted.

I'm sure that much of the internet bickering about quality is a function of sample variability, take for example the recent test by a prestigious French photo magazine of the 35 1.4L, they concluded it's a dog, my sample comes as close as makes no difference to the Leica Aspheric 35mm. Or take the experiences of Erwin Putts, the Leica pundit. He's recently bought a 5D and he's been acquiring some lenses to go with it. I haven't read his reports exhaustively but I get the impression he hasn't been able to find a single perfect Canon lens, after sifting stock he's down to accepting relatively low decentering problems.
Title: Canon L lenses and quality control
Post by: boku on April 09, 2006, 01:42:33 pm
Quote
Oops, sorry I meant to refer to the Canon 24-105 f4 L lens. Sorry for any confusion
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Stephen,

I had a 24-105. It was clearly a dud with regard to flare. Way beyond acceptable or repairable. Regarding flare, I had a bad copy - much worse than others.

This lens also exhibits above average image distortion at the extremes of its zoom ranges. All copies do because of the design. It is not a matter of a bad copy and it is not a real critical flaw bacause on images where there are straight lines distorted, Photoshop and plugins can correct. But it is above average.

Ultimately, I exchanged the lens in for a 24-70 because there were too many issues that disatisfied me. Somebody else got my dud. Think about it.

In general, most Canon L lenses do not have the quality variation I experienced. There are differences and I have no idea how the rest of my collection compares to other copies becauase I am satisfied and have no patience or opportunity for comparison, especially pre-sale.

I live in the greater-Cleveland, Ohio area. If you want to buy a Canon L lens from a Camera store you need to have them order it. Since no one stocks L glass and they hire near-idiots, I buy everything online. That eliminates any possibility of cherry-picking.

With regard to cherry picking: If you choose to do that, and if you have a retailer that permits it, how do you know the last person in the store didn't buy the primo copy before you got there? Meanwhile, your copy was out of the box, pawed, and rejected.
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 09, 2006, 02:00:24 pm
Bob,

Needless to say I have no vested interest in plugging for them, but just for the record you CAN return lenses to B&H if you aren't satisfied. Here is their return policy:

http://www.bhphotovideo.com/bnh/controller...urnExchange.jsp (http://www.bhphotovideo.com/bnh/controller/home?O=productlist.jsp&A=getpage&Q=HelpCenter/ReturnExchange.jsp)

Cheers,

Mark
Title: Canon L lenses and quality control
Post by: Ray on April 11, 2006, 01:00:52 am
I think most of us who have a accumulated a number of lenses, whether they be Canon, Nikon or 3rd party, will have experiences of duds and sub par performance. My biggest surprise was the Canon 400/5.6 prime. I expected it to be sharper than my 100-400 IS zoom. It was in fact not as sharp, yet it appeared to be in pristine condition. Before getting my refund, the store sent it away for calibration. I tested it again and found it to be marginally better but still worse than the zoom.

My first copy of the EF-S 10-20 had a focussing problem. The second copy was simply not as sharp at 15mm as my Sigma 15-30. The third copy I tested was almost as sharp as my Sigma, did not appear to have any focussing problems, so I bought it. However, I now have little use for it because the Sigma 15-30 on my 5D is more useful.

It's worth noting, if I'd bought the Canon 400/5.6 prime before the 100-400 zoom, I would probably have assumed that the 400 prime was average and no worse than what one could expect for the price. On buying the 100-400 zoom, I would probably then have raved about how good the zoom was. It's all relative.
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 11, 2006, 08:30:40 am
Ray, whether it is relative or not I think this thread reveals that there are quality control issues at Canon. As for relative - yes and no. Yes in the sense that one usually compares one thing relative to the next. No in the sense that I can sit back, look at print in isolation and ask myself whether what I'm seeing is megabucks worth of crisp detail.
Title: Canon L lenses and quality control
Post by: Ray on April 11, 2006, 09:45:01 am
Quote
Yes in the sense that one usually compares one thing relative to the next. No in the sense that I can sit back, look at print in isolation and ask myself whether what I'm seeing is megabucks worth of crisp detail.
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Mark,
You can ask yourself these questions but you can't answer them unless you have seen and remembered what true megabuck quality looks like. Whether the comparison is with another lens you own, a memory of what a sharp print should look like, or what an actual sharp print looks like because you already have a few, it's still a comparative process.

We should also bear in mind that most prints that are not as sharp as they could be, are 'not sharp' as a result of misfocussing and/or an inadequate shutter speed.
Title: Canon L lenses and quality control
Post by: D White on April 14, 2006, 03:14:41 am
I have had a 600f4L and an 85f1.2L that both back focused and thus initially performed poorly at full aperture when used with autofocus. Once I finally realized the problem, it was rectified by Canon. The 85L also showed what was likely a de-centering problem, with the plane of focus off perpendicular, as if it was a tilt and shift lens. This too was finally corrected by Canon and now performs stunningly. Since then, I have had no further problems with the many other lenses I have acquired. I know of one other person who had initial back focus problems on a 600f4 and a 300f2.8 before correction by Canon. Thus, if you are aware that you are not getting full potential from your lens, Canon seems capable of solving it.
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 14, 2006, 08:43:16 am
If these extremely expensive "L" lenses are the "best Canon makes" and the cream of the crop, it demonstrates they have serious quality control problems in that company - and I have nothing against Canon - I use a 1Ds - I am simply making an observation that when one pays top dollar for the best professional equipment a company manufactures, one expects these units to be inspected by hand individually before they leave the factory.
Title: Canon L lenses and quality control
Post by: wtlloyd on April 14, 2006, 10:32:35 am
I've purchased most of my Canon lenses used - but I wouldn't in the future. I sent the lot in to Canon factory service to be checked out, with some noticable improvement in 2 of the lenses. I will now buy new, and send in for a free calibration/checkup close to the end of the warranty period. I'm about to send my 600mm in, I've only a few weeks left to do so.
Gone are the days Canon would calibrate all your lens and bodies for free - min charge now is $60-$80 per lens, and up. This pretty much negates the minor savings on a mint copy of most lens. Canon won't go by the mfg date code on the lens, they insist on a dated sales receipt for the warranty.
Title: Canon L lenses and quality control
Post by: lensfiend on April 18, 2006, 04:04:20 am
Quote
Hi Folks,
I'd like to buy a  Canon 24-85 f4 L-series lens and I've being doing as much research as I can to ensure I understand the optical strengths and weaknesses of this lens. However, I've been suprised, (after visiting numerous forums), at the number of these lenses that seem to be returned because the purchasers had (apparently) got a 'poor' example of the lens. Am I seeing a 'biased sample' or is purchasing any lens more hit and miss than I ever realised? I'm not a 'pixel peeper' and certainly don't want to start 'testing' a new lens to ensure I've got a 'good' example.
Any comments or insight would be appreciated
Regards
Stephen
[a href=\"index.php?act=findpost&pid=62200\"][{POST_SNAPBACK}][/a]


I have seen it happen on Both Nikon and Canon lenses.  It is not as often as I think the internet makes it seem though.  The Nikon included a 400mm 2.8, 17-35mm 2.8 and the canon I had was the 300mm f/4.  Once sent in for calibration they were fine. Except the 17-35mm Nikon because Nikon insisted it was within specs but relented after I sent them sample images and the camera body.
Title: Canon L lenses and quality control
Post by: jjphoto on April 19, 2006, 10:59:22 am
It's sad that this is an issue at all. I have plenty of Leica glass, all of which performs as expected with no seeming "irregularities" or quality control issues. In fact, I can accurately compare every Leica lens I own with their published MTF charts for the same lenses and can see how accurately they seem to correspond.

I would be happy to pay more for a lens if it would guarantee performance. Thatís why I'm a big fan of Leica. Many Canon lenses are easily as good as Leica glass, the real problem in my mind is why should I spend big dollars on Canon glass and gamble on the quality of the sample that I happen to receive when I can buy almost any sample of a particular Leica lens and feel very comfortable that it will perform as expected.

I don't understand why Canon allow so much sample variation as it is obviously a thorn in their side and one that many, many people are aware of. It almost seems to be a business decision to pump out products as fast as possible, regardless of quality. Maybe itís cheaper to fix the few lenses that are returned than to spend big bucks on retooling to make sure that they never come back in the first place.

JJ
Title: Canon L lenses and quality control
Post by: gear junkie22 on April 20, 2006, 07:39:58 pm
This sample variation certainly doesn't apply to just Canon.  I just dumped about $5k in Canon gear to move to Nikon, because the D200 build quality smokes the hollow feeling 5D and 30D, while still providing all of the features that I really need.  I never got a bad sample out of about 8 Canon lenses (3 of them L glass).

However, now that I have moved to Nikon, I have had nothing but problems trying to get a decent lens.  (Although I did get lucky with a banding-free D200!)  So far, I am 0 for 3, on trying to get decent (not perfect) pro lenses.  I have tried 2 70-200 VR lenses (The first had a large metal shaving on an interior rear element.  The second sample had an elemnent out of alignment such that the bottom right corner was totally out of focus.)  I am also trying to get my second sample of a 105VR lens.  (The first sample had an aperture blade that was not located correctly, and created a diamond-shaped opening, instead of a circle.  This same sample also had a minor scratch on one of the aperture blades.)  All of the Nikon lenses that I have sampled so far have had between 10 and 20 dust particles within.  So far, I am completely disappointed with Nikon, and plan to write a letter to their consumer relations department to inform them of their poor QC.  

I am going to try one more sample of each lens.  If they are garbage, too, then I plan on moving back to Canon and settling with a 30D until the 5D upgrade (with weather sealing and an MLU button please!!!) arrives.

I LOVE the D200 body, but am at my boiling point trying to get a decent Nikon lens!

OK, [end rant/]
Title: Canon L lenses and quality control
Post by: thompsonkirk on April 20, 2006, 07:50:14 pm
I agree with the posts that have said Casnon has a quality control problem, but the problems I've had - with zoom lenses - have had to do with the way the lens was calibrated, not with the L glass itself.

You can return lenses under warranty to Canon Service for re-calibration, & my experience is that my two duds (a 17-40 & a 24-105) turned out to be stellar prerformers with proper adjustment.

I just think it's a bit of a disgrace that Canon doesn't catch these things in the first place!
Title: Canon L lenses and quality control
Post by: LynnB on April 21, 2006, 08:36:57 am
Hi Stephen,
I recently purchased a 24-105/4L lens for my 5D and found quite noticeable chromatic aberration (red/green) at 24mm in bright light, particularly at the edges but also near centre frame. I returned it and exchanged for another copy which still shows some R/G CA but to a lesser extent, so I am keeping it.
Barrell distortion is noticeable at wide angle but easily corrected in PS.
Regards,
Lynn
Title: Canon L lenses and quality control
Post by: Ray on April 21, 2006, 08:48:49 am
Quote
It's sad that this is an issue at all. I have plenty of Leica glass, all of which performs as expected with no seeming "irregularities" or quality control issues. In fact, I can accurately compare every Leica lens I own with their published MTF charts for the same lenses and can see how accurately they seem to correspond.

I would be happy to pay more for a lens if it would guarantee performance.
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I tend to agree. I think all lenses should ship with a set of individual MTF charts. That's definitely going to increase the cost but I expect that at least part of that additional cost would be offset by the higher price that demanding people would pay for the cream of the crop. Each model of lens could be divided into Grade A, B and C. Grade A could sell at a significant premium; grade B at a small premium and grade C at roughly current prices.

We could then have endless debates as to whether or not a Grade A Sigma 12-24mm at double the price of a Grade B is worth the extra cost   .
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 21, 2006, 09:08:44 am
Quote
Hi Stephen,
I recently purchased a 24-105/4L lens for my 5D and found quite noticeable chromatic aberration (red/green) at 24mm in bright light, particularly at the edges but also near centre frame. I returned it and exchanged for another copy which still shows some R/G CA but to a lesser extent, so I am keeping it.
Barrell distortion is noticeable at wide angle but easily corrected in PS.
Regards,
Lynn
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Based on my copy, there should be VERY LITTLE C.A. with this lens. I've also noticed the slight barrel distortion at W.A., and I agree it is easily corrected.
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 21, 2006, 09:11:59 am
Quote
I tend to agree. I think all lenses should ship with a set of individual MTF charts. .................Each model of lens could be divided into Grade A, B and C. Grade A could sell at a significant premium; grade B at a small premium and grade C at roughly current prices.

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Ray, did you really mean that? I think they should simply set a standard for what "L" means, test each piece before it is intended to go out the door and not ship anything that doesn't meet it.
Title: Canon L lenses and quality control
Post by: Giedo on April 21, 2006, 09:13:04 am
If I were a camera / lens tester, I would get 10 similar lenses at 10 different locations and start testing as to provide some objective facts instead of all this hearsay.

Actually I found a very objective way to get my lens tested. I provided my Tamron Macro lens to Klaus from www.photozone.de. He tests lenses individually that are provided by readers from his website. result: fabulous lens. But I have to say that the quality before and after this test is exactly the same ;-)) So in that sense I agree with Ray.
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 21, 2006, 09:22:14 am
Quote
If I were a camera / lens tester, I would get 10 similar lenses at 10 different locations and start testing as to provide some objective facts instead of all this hearsay.

Actually I found a very objective way to get my lens tested. I provided my Tamron Macro lens to Klaus from www.photozone.de. He tests lenses individually that are provided by readers from his website. result: fabulous lens. But I have to say that the quality before and after this test is exactly the same ;-)) So in that sense I agree with Ray.
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Giedo, don't dismiss the findings of experienced photographers as "hearsay". I've been making photographics for 50 years and I know what I expect from USD 1200 worth of lens. For most people the idea that you could put together a sample of ten copies for comparison testing is totally on another planet. Not even the people who test this equipment on the various websites we usually read do that. A sample of one is not a valid testing procedure - that much I agree with you, but that is a separate issue from the fact that there is enough evidence of a QC problem in Canon's "L" department that they need to look into it. If the best they make is supposed to be the best they make, they should do more to ensure each piece is properly tested to a minimum acceptable standard for "L" before it leaves the factory.
Title: Canon L lenses and quality control
Post by: jjphoto on April 21, 2006, 10:16:54 am
Quote
I think they should simply set a standard for what "L" means, test each piece before it is intended to go out the door and not ship anything that doesn't meet it.
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"L" only refers to extraordinary component elements or manufacturing techniques (ie. glass such as flourite, UD or aspherical elements).

"L" is NOT an indicator of image quality, only of the effort and cost involved in manufacturing a lens. Some, maybe many, non "L" lenses outperform "L" lenses. I have a 100/2.8 USM (NON "L") which outperforms the other 3 "L" lenses  I have.

JJ
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 21, 2006, 10:30:21 am
Thanks for clarifying the meaning of "L". That is helpful. Underlying that, one supposes they do these things to achieve a higher quality standard. One should therefore expect that for any Canon lens with the same focal length and f/stop range an "L" version should deliver better image quality than a non-L version. That much said, perhaps they don't make any pair of lenses like this, so one cannot really make an apples-to-apples comparison of the same thing in an "L" versus a "non-L" version! All I know is that if I pay 1200 bucks for an "L" lens, which is supposed to be their best, I don't want to habe to worry about variable sample quality to the extent of noticeable differences from one copy to the next.
Title: Canon L lenses and quality control
Post by: jjphoto on April 21, 2006, 06:15:04 pm
Quote
All I know is that if I pay 1200 bucks for an "L" lens, which is supposed to be their best, I don't want to habe to worry about variable sample quality to the extent of noticeable differences from one copy to the next.
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I hear you girlfriend, but that aint the real world. Personally I would only buy from a reputable dealer who is willing to replace the lens if it doesn't meet your performance standard.

JJ
Title: Canon L lenses and quality control
Post by: Ray on April 21, 2006, 10:21:26 pm
Quote
Ray, did you really mean that? I think they should simply set a standard for what "L" means, test each piece before it is intended to go out the door and not ship anything that doesn't meet it.
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Mark,
I really mean it. I hate waste. I understand when Intel produces a processor chip that doesn't meet specification but still works, they label it as a slower processor. They don't necessarily junk it. (At least, that's what I've read, but it could be a myth.)

I suspect it is not practical or economical  to manufacture a complicated item like a lens and ensure that each copy is exactly the same. If it's necessary to test each individual lens to ensure performance consistency, then let some of us poor folks get the rejects at a discount. As long as I'm provided with reliable information regarding the lens' failing (through an MTF chart, for example) I might be able to live with it.
Title: Canon L lenses and quality control
Post by: David Anderson on April 22, 2006, 02:10:18 am
I borrowed a 24-105 L for a rafting trip from Canon CPS, and was happy with the shots, yes there was some distortion issues, but nothing that the average reader would see.
It's an easy lens to live with if you don't want to change lenses all the time, ot like me you were in a situation that demanded low weight.

A couple lenses I've sent to Canon for calibration have come back with very good results, like my 16-35, now tack sharp at both ends..

One last thing, make sure you check the focus calibration on your camera with other lenses before you blame just the lens, I found one of my markII DS's front focused only enough to be noticed on the fast lenses wide open.
After another trip to Canon it's all better.

David.
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 22, 2006, 08:04:23 am
Quote
I suspect it is not practical or economical  to manufacture a complicated item like a lens and ensure that each copy is exactly the same. If it's necessary to test each individual lens to ensure performance consistency, then let some of us poor folks get the rejects at a discount. As long as I'm provided with reliable information regarding the lens' failing (through an MTF chart, for example) I might be able to live with it.
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Ray, what you are saying makes some sense, but I think it would be an administrative nightmare for the manufacturer and the retailer. It is a pandora's box for endless disputes with customers, while the manufacturer still needs to put the resources into individually reporting on each piece it manufactures. As complex as the manufacturing may be, I believe they are technically savvy enough to set a MINIMUM standard for a particular grade of lens (which would be high for an "L" lens) and meet it every time. If they surpass it from piece to piece, well that's a bonus for the guy or gal who buys it - but not a corporate obligation, while the rest of us know what we buy meets the minimum standards for the price point.
Title: Canon L lenses and quality control
Post by: Ray on April 22, 2006, 09:38:49 am
Quote
Ray, what you are saying makes some sense, but I think it would be an administrative nightmare for the manufacturer and the retailer. It is a pandora's box for endless disputes with customers, while the manufacturer still needs to put the resources into individually reporting on each piece it manufactures.


Mark,
I honestly can't see why this should be the case. Three different grades of the same model of lens would in practice simply be 3 different models of lenses which happen to all have the same basic characteristics. If a customer decided to upgrade from Grade C to Grade A and discovered that his old Grade C was in fact better than the new Grade A, then one would expect that a refund or replacement would be provided without drama. The only administrative nightmare that might occur would be in the QC and MTF testing department of the manufacturer, and rightly so.

In other words, full testing and grading of each individual lens is the best form of quality control one can have. Mistakes would be made, but over all quality within each grade would be more reliable and consistent. Such a system would also lend itself to better and more informative scrutiny from reviewers who would have a better standard against which to judge a lens, it's own MTF chart and/or a different grade of the same model.

Such a system should also help the manufacturer (or brand owner) with marketing decisions and enable them to better serve the customer. They would get a clearer idea of the demand/quality/price relationship for particular designs and types of lenses. The consumer would also have greater number of choices. Is that a bad thing?  
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 22, 2006, 11:04:39 am
No, it is not such a bad thing per se, but it just won't happen - no way I can imagine Canon firstly admitting to the who concept, then sitting down to work out these quality grades and conform every lens they manufacture, say within the "L" line to one of those grades.
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 22, 2006, 11:11:12 am
Quote
I hear you girlfriend, but that aint the real world. Personally I would only buy from a reputable dealer who is willing to replace the lens if it doesn't meet your performance standard.

JJ
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JJ, I see you are new to this Forum. I'm not a girl, not your girlfriend (your real girlfriend - if you have one - should be insulted   ) and we have standards of dialogue here which I would recommend you respect.

Apart from that, I agree with you about having return privileges for such purchases - very important.

Cheers,

Mark
Title: Canon L lenses and quality control
Post by: Ray on April 22, 2006, 12:45:16 pm
Quote
No, it is not such a bad thing per se, but it just won't happen


Mark,
You are probably right. It won't happen, but I still think it's a good idea. The best we can hope for is that QC methods and manufacturing tolerances will improve with advancing technology. In the meantime I'll just have to do my own testing.

I was in Chinatown in Bangkok recently buying a 580EX flash unit. The price was so good I enquired about the Sigma 12-24, which is a lens I want but which has a reputation for quality variability. Because I'd already made a purchase, the store was willing to offer me a special price on the lens; much cheaper than I'd pay in Australia. I was sorely tempted, but didn't have the means with me to test the lens (ie. laptop, my own copy of the Sigma 15-30 with which I'd compare it, etc.). It was the last day before Songkran and the store was closing for the week. I didn't have the opportunity to return. I didn't buy the lens.

On reflection, this is a sad state of affairs when a customer wants a lens but doesn't buy it because he doesn't have time to test it.
Title: Canon L lenses and quality control
Post by: macgyver on April 22, 2006, 12:55:34 pm
Quote
JJ, I see you are new to this Forum. I'm not a girl, not your girlfriend (your real girlfriend - if you have one - should be insulted†  ) and we have standards of dialogue here which I would recommend you respect.
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Easy now mark, JJ was not calling you a girl.  It's an expression.

Also, how long does it typically take for one of your bodies/lenses to go to and from canon service?  I would love to send one in, but I shoot for a daily and have a hard time finding an opening to do so.
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 22, 2006, 01:11:51 pm
macgyver, OK, I've never been treated to that expression before. Thanks for the heads-up.

Sorry I can't advise about turnaround time at Canon. What country/city are you in? Here in toronto they do have a special service window for members of their accredited Professionals customers, and I believe they provide quite rapid turnaround for those folks - but I suppose it also depends on what you need done.
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 22, 2006, 01:16:05 pm
Quote
I was in Chinatown in Bangkok recently .................... I didn't buy the lens.

On reflection, this is a sad state of affairs when a customer wants a lens but doesn't buy it because he doesn't have time to test it.
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I would have made exactly the same decision under the circumstances.

BTW, did you take any shots in Chinatown at night there? I found it very photogenic.
Title: Canon L lenses and quality control
Post by: Ray on April 22, 2006, 09:51:06 pm
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BTW, did you take any shots in Chinatown at night there? I found it very photogenic.
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Unfortunately not. I was travelling with a female companion and felt somewhat constrained with regard to photographic activities. However, I plan to revisit Angkor Wat in August/September, by myself, and should then have an opportunity to test a few copies of the Sigma 12-24, a lens I'll need for those huge structures in the jungle. I'll check out Chinatown by night also   .
Title: Canon L lenses and quality control
Post by: Anon E. Mouse on April 23, 2006, 07:15:12 am
Lens manufacturers manufacture their lenses to defined tolerances. They are also under a great deal of preasure to keep prices down - $1,200 is not a lot of money for the technology you are buying. So they are balancing the consumer demand for inexpensive optics with the demand for high-quality optics. And the advances in optical design and manufacturering today are amazing. Try comparing your modern zoom lens with one produced in the 70s.

Has anyone here ever made an MTF curve for a lens? Do you know how long it takes? (Hint: 4 - 5 hours.) Do you know how much those machines cost? Then to place every lens on the machine and generate curves would be such an investment to the manufacturer that the cost of the lenses would shoot up. I seriously doubt anyone would want to pay for it.

Then there is another headache for the manufacturer. Customers comparing their MTF results and demanding their unit match the best sample curve they can find. Not only would this make your lenses even more expensive, but it is also silly as the MTF curve can detect variations that cannot be seen in the image. Amateur MTF "experts" are not worth the manufacturer's time.

The current system is good. If the average quality of manufactured lenses where really as random as this thread suggests, then there would be a lot more complaints than you see here. You have a better chance to get a good lens than you do a bad one.
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 23, 2006, 07:52:10 am
Anon, thanks. You've spelled out in detail why I think it is impractical to try implementing refined systems for grading the eggs. You speak of "defined tolerances" and I think that is where the issue is. While the real cost has come down and the quality gone up over the years, that is all sunk-cost and sunk-benefit if you will - people evaluate now for now and ask whether my 1200 dollar lens is as sharp and free of distortion as the next guy's or gal's, and if there are visible differences we get uncomfortable. So the issue is to define these tolerances in a way that keeps us happy - especially those buying at the high end, regardless of whether the high end is now lower than it was in 1970.
Title: Canon L lenses and quality control
Post by: Ray on April 23, 2006, 09:34:22 am
Anon and Mark,
Thanks for playing the role of Devil's Advocate. A good idea always needs testing   . Let me now dispel some of your negativity (if not completely annihilate it   ).

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Has anyone here ever made an MTF curve for a lens? Do you know how long it takes? (Hint: 4 - 5 hours.) Do you know how much those machines cost? Then to place every lens on the machine and generate curves would be such an investment to the manufacturer that the cost of the lenses would shoot up. I seriously doubt anyone would want to pay for it.


Photodo is the only company I know of that has produced reliable MTF data for a variety of lenses. Their numerical rating for each lens may be a bit suspect because it's weighted. However, their graphs speak for themselves.

As to the cost in Sweden, I've come across figures of $700 per lens. It seems a believable figure and it's quite extrordinary that Photodo should provide this valuable resource completely free.

A $700 on-cost would be of course a major obstacle for any manufacturer trying to compete in a global market. However, Photodo is a small office testing relatively few lenses. MTF testing on a massive scale in an industrial context would involve industrial robots and streamlined processes. Add to that the fact that wages in China are considerably lower than in Sweden, you're probably going to come up with an additional cost of $50 per lens, a cost which could be borne by the premiums on Grade A and B lenses.


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Then there is another headache for the manufacturer. Customers comparing their MTF results and demanding their unit match the best sample curve they can find. Not only would this make your lenses even more expensive, but it is also silly as the MTF curve can detect variations that cannot be seen in the image. Amateur MTF "experts" are not worth the manufacturer's time.


This is a complete red herring. In the early 1980's, I bought a pair of Celestion SL600 loudspeakers. They shipped with individual frequency response charts. I don't know for sure if this was a scam and the charts just  theoretical, based on the design rather than the actual speaker, but the chart of the left speaker was in fact different from that of the right speaker, indicating they were real tests.

Did I buy myself a sound level meter and build myself an anechoic chamber so I could test whether the left chart was really different from the right chart? Of course I didn't. I've got better things to do with my time. And so have most people who buy lenses.

Providing individual MTF charts for lenses is really about transparency. Joe Bloggs is not likely to have the means or the inclination to question the veracity of the MTF charts, but reviewers like Photodo, or even Popular Photography, do have the means.

The current situation is that only Zeiss and Leica provide MTF charts for real lenses, on their websites. Whether or not individual Leica or Zeiss lenses have shipped with an MTF chart specific to the that lens is not clear to me. However, it does seem clear that Canon's published MTF charts for all their lenses listed in their Lens Work books, and on the USA website, are all theoretical.

Even if the cost of producing a set of real MTF charts for a particular lens is an astronomical $700 in Japan, one can't help wondering why Canon do not give us a set of MTF charts for even a 'typical' real lens.

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The current system is good. If the average quality of manufactured lenses where really as random as this thread suggests, then there would be a lot more complaints than you see here. You have a better chance to get a good lens than you do a bad one.


No! Another red herring! There are many lenses out there that have sub-optimal performance but the owners are just not aware of it. It's only the few 'fanatics' on forums such as this who are aware that a problem exists. If you haven't got something else to campare with, or are not even inclined to do such a comparison, you're going to be blissfully ignorant.

If Mark's first copy of the 24-105 was the one without the flare problem, he wouldn't be aware that another copy with the flare problem was actually sharper.
Title: Canon L lenses and quality control
Post by: Anon E. Mouse on April 23, 2006, 11:13:33 am
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MTF testing on a massive scale in an industrial context would involve industrial robots and streamlined processes. Add to that the fact that wages in China are considerably lower than in Sweden, you're probably going to come up with an additional cost of $50 per lens, a cost which could be borne by the premiums on Grade A and B lenses.

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. You need to calculate the interest on that $50 that piles up as the product sits in stock (or rather how long it take for the manufacturer take to repay the investment made in that product). In maufacturing today, engineers worry about shaving off fractions of a penny to keep prices down. Adding $50 to each product at manufacturing is huge!

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



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Joe Bloggs is not likely to have the means or the inclination to question the veracity of the MTF charts

But if Joe's chart is not the same as Michael's chart of the same lens, he will complain and demand one like Michael's. And with the internet there is a good chance there will be lots of charts to compare. 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 (at least as the MTF curve is concerned) off the line which translates into higher prices or manufacturers dropping lenses and maybe going out of business.

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.

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No! Another red herring! There are many lenses out there that have sub-optimal performance but the owners are just not aware of it.

How many? Any proof of that would be welcome.

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?

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.

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.
Title: Canon L lenses and quality control
Post by: Ray on April 23, 2006, 01:12:11 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.)
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 23, 2006, 02:06:20 pm
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.  
Title: Canon L lenses and quality control
Post by: Ray on April 25, 2006, 01:28:21 am
May I say Mark, I think you'd make an excellent moderator   .
Title: Canon L lenses and quality control
Post by: Mark D Segal on April 25, 2006, 08:40:19 am
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.