Lenses and Quality Assurance

[steve_rasmussen]

There has been a world wide trend in Quality Assurance to not use mass

inspection as a means to meet customer demands and expectations.

Process controls have been the emphasis, both on the process inputs

and in process as well. There is still some inspection and test done,

especially in optics. With tolerance ranges in the microns, it is

difficult to control the process so well that a test is not needed.

Leica still inspects and tests, and their lens element rejection rate

is 3%. They have also been known to use a tighter tolerance range than

companies like Minolta. Leica is said to use half as large a tolerance

as Minolta. But, the Japanese optics companies are based on the Dr.

Taguchi and Dr. Deming quality philosophies. One important aspect of

these is that loss is generated with any deviation from the exact

dimension(Taguchi Loss Function). So, Japanese companies do not like

to use the entire spread of the tolerance range. There is too much

loss when lens elements are made at the edges of the tolerance range.

A lens made with many such elements would most likely not pass final

test. The dimensions of the camera body lens mount and lens rear take

an exacting machining process which has to match the precision of the

optics. A 1/20 mm mistake will cause the lens to not focus at

infinity. Leica lenses always fit the same, tight and smooth. Asahi

Optical's lens to body fit is not always the same. But then again, if

Leica made a 67, it would cost $6000+. Japanese Quality Assurance is

also based on statistical thinking and continuous process improvement.

They are all about reducing process variation. They try to improve the

process to the point that very little scrap is detected at inspection.

But any optical company needs a good inspection process because the

process before it is not perfect. You don't want the customer to find

bug parts in the glass or a lens that won't fit on the body.

Asahi/Pentax still has a way to go before they can meet Deming and

Taguchi's dream for Japan.

[paulstenquist]

Unfortunately, I'm not sure that they're progressing. The early Asahi Pentax lenses for the Spotmatic and the K-series 35mm cameras were a model for the industry. I'm very pleased with my 67 lenses, but I'm not sure they're the equal of some of the classic 35mm Pentax lenses that I own, such as the Pentax SMC Takumar 50/14 or the Pentax SMC 85/1.8.

Paul Stenquist

[kelly_flanigan1]

The Bolex Switars I have in D mount for movie cameras are of super quality; built with Swiss pride and no ISO 900X marketing hype.... The 13mm F0.9; 5.5mm F1.8; 12.5mm F1.5 ALL are a hell of alot better than any other regular 8mm lenses...........

[tony_cunningham]

Steve - Kelly is right what you are referring to is the ISO 9000 series quality assurance hype. This seems to me to have had little or nothing to do with customer requirements or expectations, just money making by the approval bodies. I have direct experience (not photography related) of taking justified customers� complaints to a factory manager and being told. �We have ISO 9001 approval and cannot make mistakes�. The answer to the question: Was the product checked? was �No, of course not, it is not necessary�.

 

> There is still some inspection and test done, especially in optics.

 

Well perhaps Leica are still doing some QC, but I wonder how many others are. My Pentax (UK) repair experience has been good up to now, in spite of the stories, but I bought a new Fuji GW 670 (with 90 mm lens) from Robert White earlier this year. It had a large air bubble between the front elements. It could never have been given even the most cursory manual or automatic QC check. Robert White changed it at once for a GW 690 that they had in stock. This lasted 40 films of careful use and the shutter mechanism jammed. Firstly Fuji (UK) apparently tried to get out of a repair under warranty and later, after weeks of waiting, and a lot of pressure from Robert White, they carried out a hasty repair. The inside of the camera now looks as if has been attacked by a cat and there is considerable dust clearly visible inside the rear elements. The camera does work OK though and I have not dared to let Fuji get near it again. However this camera, still just a few months old, will have virtually zero value on the second-hand market.

 

A Fuji GSW 690 (with 60 mm lens) purchased at the same time is fine, so I suppose it is a lottery.

 

Having heard about the Pentax problems I asked Robert White if they could recommend any manufacturers of professional MF equipment that could both supply and maintain quality. I had expected a response like buy Brand X, but the response was that there is a shortage of camera technicians and that at least for repair, many / most of the big names seem to be suffering quality problems. So don�t be too quick to dump Pentax!

 

My ideal supplier of new photographic equipment (or anything else) would state �NOT ISO 9000 APPROVED� on its products. I wonder if Leica meet this requirement? Hasselblad perhaps do not, as Fuji seem to be making much of their equipment these days!

[allan_jamieson2]

I've not had too much trouble with the quality of my Pentax 67 equipment,

some inconvenience maybe! I've now ditched all my Takumar lenses,

including a 75mm, 105mm and a 135mm lens, just because I didn't think that

they were quite as good as some of my other lenses; in particular my 45mm

and 55mm Pentax lenses. But, that is maybe a very subjective evaluation of

quality. The 75mm images just didn't look quite as sharp as the 55mm

images. The 105mm could produce very sharp images at certain apertures,

but the lens had a strange colour to it and the 135mm was pretty good at

close up stuff, but not all that good focused at infinity. Probably other

examples of these same lenses would have been a lot better than this and

some maybe worse.

 

One thing that I did notice is that before I sold my Pentax 67, I tried to fit a TTL

prism to it, sounds simple doesn't it? Well, could I get that prism to sit properly

on the camera! It rocked backwards and forwards and wouldn't sit down

properly on the contacts; needless to say it wouldn't work. But, the plain prism

that I bought with the camera fitted perfectly, they were both late model types,

with Pentax in large white lettering. So, I would agree in that instance that

Pentax must have had a very wide manufacturing tolerance when it came to

making these prisms. I would have expected any prism ever made for a

Pentax 6 x 7 or 67 to have fitted reasonably well on any camera, but that

might be a touch optmistic.

 

As for the Fuji cameras, I'm surprised to hear the comments above about the

condition of the GW670III with the air bubble in the front element. That really

stinks, not much sign of quality control there. But, a very good example of why

it pays to buy equipment from a company like Robert White, who will always

support their customers in any dispute. Given the botched repair job on the

replacement camera I would have insisted on either a brand new

replacement for the first replacement! Or, a complete refund, which Robert

White would most probably have given. I know of one photographer who

bought a brand new Mamiya 7II outfit from them and the first camera proved

faulty. Robert White's replaced it straight away and then the second one had

the exact same fault as the first one. They gave the guy all his money back

and took back all the lenses that he had bought with the camera. Robert

White's have the clout to deal with Fuji, Pentax, Mamiya and all the big

manufacturers and I'm quite sure that they wouldn't be left out of pocket at the

end of the day. I bought a second hand GSW690II from them a few years back

and it's been great, I've had absolutely no trouble with the camera at all.

Maybe Fuji's build quality has slipped a bit with the mark 3 versions?

[tony_cunningham]

Allan - interesting comment about the Mamiya. I actually asked Robert Watson if I might not be better switching to the Mamiya 7 and that was when they commented that most makes were having problems - and from what you say also with manufacturing, not just with service. I agree with what you say about Watson, they are very good. I did not return the Fuji for a third time, because they had pushed Fuji to get it repaired for a shoot in Italy. I took it with me and it worked fine, so it has now taken about 80 films. My problem will be if I try to sell it.

 

Sorry about the divergence from the main subject of this forum, but I though it might be of interest to any of you thinking of dropping Pentax. By the way I purchased the Fuji rangefinders, because I cannot live with 1/30 sec flash sync and need LS versions of the 90 mm and 55 mm lenses. The lens I most enjoy using of any I have ever had on any system is the 165 LS, but I will not purchase a 25 year old 90 LS!

 

Incidentally I have had two P67 bodies, one very old with no MLU and one quite new. The prism meter fell/falls off both of them when used in the portrait mode.

[allan_jamieson2]

Tony, going by what you've posted here, the replacement Fuji camera failed

after something like 40 rolls of film being put through it. That's fairly pathetic

reliability, any camera that fails after such little use should be replaced and

not repaired by the manufacturers, whether it is Fuji, Pentax or whoever. Fuji

could easily sell nearly new, properly repaired cameras on to their dealer

network and still make something back, without expecting customers to put up

with the inconvenience of being without their new cameras for any period of

time. And any repair work carried out by Fuji should be to a good professional

standard and not leave the inside of the camera looking all chewed up as per

your description. Speaking personally, I wouldn't have accepted a repair to

the second camera if I'd been in your position, especially given the fact that

you had already to return one faulty camera. It isn't asking for much when

you're buying a new camera to get one that actually works as it is intended to,

without needing a major service after only 40 rolls of film, which is only 320

images on the 6 x 9 cm format. Many photographers could take that many

images on one busy day.

 

You are obviously unhappy about the condition of your Fuji camera, even if it

is in working order. My old Fuji GSW 690II is in full working order and

extremely clean inside and outside; why should you settle for anything less? It

would be worth contacting Fuji UK about this matter again and request that

they replace the camera with a brand new one. If they value their customers, I

think that this is not asking for very much under the circumstances.

[steve_rasmussen]

Here's my opinion on Takumar vs Pentax lenses and Asahi vs the newer bodies. All of my Takumar lenses fit the camera body well, whereas my lenses that don't fit so well all seem to be Pentax. Yet, some of my Pentax lenses do fit OK. On the optical side, there really is not enough difference between the Takumars and Pentax to say that one is inferior. The 150 and 400 Takumars are gems but so are the Pentax 55 and 45.

 

Pentax's problem with quality is time dependant. My outer bay lenses fit very well on my Asahi but poorly on my Pentax 67. My Helicoid allows metering on my Asahi but on my Pentax 67 it does not work. It is a body problem, not the Helicoid. My feeling is that with the increased production, process variablity has increased. Production after 1989 is when I started to notice variations in fit. I still prefer the SMC Takumar lenses and MLU Asahi bodies.