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Where the sharpness comes from: A tour of Sigma's factory

By dpreview staff on Sep 20, 2013 at 19:04 GMT

Some people are happy to shoot with lenses and think only of the results, but it can also be fascinating to think about how such complex, precision pieces of engineering are made. Some insight is provided by Dave Etchells over at Imaging Resource, who has just posted a story about his visit to Sigma's factory in Aizu, Japan. Etchells follows the process from shaping the lens surfaces, to polishing, assembly and testing.

However, no matter how hard you try, you can't make every lens perfect - as Lensrentals Roger Cicala explains in his recent blog post. He looks at lens production from the perspective of manufacturability and engineering tolerances, and what's done to mitigate against the unavoidable inconsistencies they bring.

Lens polishing at Sigma's Aizu factory - photo from Imaging Resource

The two articles make an interesting pair - the efforts made to make a lens as 'perfect' as possible and the reasons why that'll always be just out of reach.

Comments

Total comments: 99
Richard Franiec
By Richard Franiec (7 months ago)

Kudos to DPReview for collaborating with other industry insiders and linking to such a great read.

I spent most of my life in hi tech machining environment and I'm astonished to see such informative and easy to understand story about complexity of processes required to build world class optics. It is also a tribute to a "human factor" so often forgotten in similar articles. Dave's inside look at how serious and committed to perfection Sigma is (testing section) is priceless.Thank you Dave.

2 upvotes
AlpCns2
By AlpCns2 (7 months ago)

Brilliant article! Thank you for posting it.

0 upvotes
PeakAction
By PeakAction (7 months ago)

Very nice article! Thanks for posting it for us to read.

1 upvote
plasnu
By plasnu (6 months ago)

Yep.

0 upvotes
Photoman
By Photoman (7 months ago)

I have been to Leica's factory in 2007 and this reminds me of their factory (almost dropped the original Leica ur when there!).

0 upvotes
VadymA
By VadymA (7 months ago)

I was surprised to see how aged their equipment is; by the look it is probably from the 80's. No wonder they have to test every lens. Still koodos to Sigma for producing some nice lenses on such dated equipment.

0 upvotes
HubertChen
By HubertChen (7 months ago)

I am not sure what your experience is. I inspect lots of factories and this Sigma factory would be one of the most modern factories I have ever seen!

Please also do not confuse wear and tear with age.

Last but not least, it is not relevant how old a machine is, rather how it is maintained and calibrated. And by the looks of it Sigma factory management is very organized and structured, thus they would have a great maintenance program.

17 upvotes
ZiggyDeath
By ZiggyDeath (7 months ago)

It really is fairly up to date. The control on that Mitsui Seiki indicate it's probably only 20 years old at the most (it looks like it's a late 90s early 00, I can't tell for sure from the picture). And the Mitsubishi EDMs, less than 10 years old (actually probably more like 5 due to how new that control is).

You might be surprised, but even modern large jumbo jet aircraft are running on landing gears milled out by 30+ year old machines.

Comment edited 55 seconds after posting
4 upvotes
AlpCns2
By AlpCns2 (7 months ago)

Nonsense. Every manufacturer has to test every product (lenses or not) if they want to assure top notch quality and tolerances. The equipment is not old at all. And even old equipment, when maintained properly and calibrated can produce excellent and consistent products. This factory looks not only clean but very well maintained as well.

Finally, the obvious quality of the products speaks for itself. Sigma produces some of the very best lenses ever tested!

4 upvotes
Ferling
By Ferling (7 months ago)

Sure. The machines may appear old, and maybe they are. What matters is the interface tooling, (which makes the cuts). I'm sure Sigma, like most large firms, have a staff of skilled tool and die makers whom maintain them. What's missing in many of the shots are those very same workers, whom most likely didn't want to be photographed and stepped away, (one less model release to be signed).

0 upvotes
nachos
By nachos (7 months ago)

These machines look plenty modern and in excellent condition.

Machine tool manufacturers produce in low volume and so re-use as much as they can from one generation to the next. The business end of things, the software controllers and actual tooling are where development takes place, while things like the outer casing and attachment points might be the same as it was 25 years ago because there's no need to spend an engineer's time on that.

0 upvotes
zodiacfml
By zodiacfml (7 months ago)

Dp merrills studio comparison tool please. :)

1 upvote
RStyga
By RStyga (7 months ago)

I second that.

1 upvote
HubertChen
By HubertChen (7 months ago)

Great Article, great photos, interesting writing. Thanks to the Author for all the work and thanks to dpreview for sharing it here.

1 upvote
plevyadophy
By plevyadophy (7 months ago)

Thanks DPReview for that heads up. That was an excellent read which, interestingly, included a few insights into Japanese culture.

0 upvotes
RichRMA
By RichRMA (7 months ago)

If all lenses today are made on $500,000 computer-controlled machines, how come some lenses are better than others? Does it come down to design and glass materials only, or are there still variations in polish and accuracy of curvature of the elements?

1 upvote
HubertChen
By HubertChen (7 months ago)

The list of variations is quite long actually:
* Choice of Materials
* Choice of tools (the bits you put into the CNC)
* Your original design (CAD)
* Your program to turn your CAD into a part (CAM)
* Maintenance of the machine
* How intelligent you adjust for deviations, such as change of temperature
* How accurate you measure machined parts and then compensate your CAM
* Integration of your assembly process
* How your original design considers assembly tolerances
* Final quality control of assembled product and feedback to assembly process

Above list is just a very rough overview. Great initial design considering all kinds of tolerances as well as measuring your results with feedback to production in many places as well as monitoring that all these processes are carried out properly, as well as a continuous improvement that goes through all steps of productions and layers of design and management are all very crucial.

6 upvotes
yabokkie
By yabokkie (7 months ago)

it's interesting that Canon have the most automated production lines and others rely more on human (Chinese, Thai) but the results are not very different.

especially I think EF24-70/2.8L2 was designed from very beginning for efficient manufacturing but qualities are distributed over similar scale though the average is higher than all rivals.

maybe it's more for lower cost than higher quality and we as users don't enjoy the former yet. the previous EF24-70/2.8L used to be sold at just a grand, USD 1,039 (new with warranty) that I can remember, and they were hand-tuned (as well as "German" lenses made by Sigma).

Comment edited 4 times, last edit 13 minutes after posting
0 upvotes
Charles2
By Charles2 (7 months ago)

In Etchells' second paragraph we learn the factory is only 90 minutes by car from Fukushima, ground zero of a nuclear disaster slipping toward an even more disastrous sequel. Ah, the radiation!

0 upvotes
calking
By calking (7 months ago)

This is a classic forum post reply. When you can't find something negative to say about the article -- Sigma in this case -- find something else. Seriously? Fukushima. Jeezus.

2 upvotes
yabokkie
By yabokkie (7 months ago)

then users may worry less for fungus in the lens.

1 upvote
Charles2
By Charles2 (7 months ago)

Nothing negative about Sigma intended. If only the nuclear industry had the same attention to detail, Japan and the world might have been spared the ongoing disaster emanating from Fukushima.

2 upvotes
craig66
By craig66 (7 months ago)

The radiation level "90 minutes by car" from Fukushima Daiichi is most likely less that that in London or New York. In Tokyo it is about half that in London or New York.

http://monitoring.tokyo-eiken.go.jp/en/

Less hysteria please.

2 upvotes
SRT3lkt
By SRT3lkt (7 months ago)

I don't think the Sigma factory is affected by the radiation, radio active water leakage is another problem.

http://www.youtube.com/watch?v=KRuOrR4jlyA

0 upvotes
craig66
By craig66 (7 months ago)

These water leaks have been vastly blown out of proportion. The Japan Nuclear Regulation Authority has released measurements of the radioactivity in sea water sampled in the sea off Fukushima, Miyagi and Ibaraki. In all cases the measurements are either very very low or beneath the limit of detection. On this evidence, it is hard to see a risk to anything. The crisis is mostly one of perception than one of reality.

http://www.iaea.org/newscenter/news/2013/seamonitoring190713.pdf

The JRA has announced that it is commencing a huge sampling effort to measure hundreds of thousands of points and targeting next northern spring to release the findings.

0 upvotes
utomo99
By utomo99 (7 months ago)

I hope more faster lens produced and used on cameras. so we can expect better picture.
It is time for faster lens, so we can get good low light photos.
No More MP war

1 upvote
CameraLabTester
By CameraLabTester (7 months ago)

Interesting article.

Can you show us the PRODUCT SERVICE and CUSTOMER CARE next time?

.

2 upvotes
Rod McD
By Rod McD (7 months ago)

Thanks to DPR for the post and link. A good and informative read.

0 upvotes
misha marinsky4
By misha marinsky4 (7 months ago)

As a licensed optician, who spent most of his time as a lab tech, I'm impressed.

Most of what is in the photographs, is what I am familiar with. Great story.

2 upvotes
kbryd
By kbryd (7 months ago)

Yeah...very nice, but still I don't understand why two Sigma lenses I had (100-300/4EX and 10-20/3.5-5.6) were rubbish. Both were extremely out of focus, actually only one side of the image was out of focus...

1 upvote
unknown member
By (unknown member) (7 months ago)

Sigma is making its lenses differently now. Which is probably the point of them showing this video. ;)

4 upvotes
SRT3lkt
By SRT3lkt (7 months ago)

USB dock eliminates that problem

1 upvote
Silvarum
By Silvarum (7 months ago)

But USB dock available only for Nikon, Canon and Sigma mounts, isn't it?

0 upvotes
Earthlight
By Earthlight (7 months ago)

The write-up on the Sigma factory tour was the best bit of photo related journalism I have seen in a while. What an enjoyable read indeed! I must check Dave's site more often it seems.

2 upvotes
DELETED88781
By DELETED88781 (7 months ago)

Where the mis-focus comes from?

A tour of Sigma's factory

Comment edited 48 seconds after posting
1 upvote
AlpCns2
By AlpCns2 (7 months ago)

Ah, a "pro".

0 upvotes
BlueJakester
By BlueJakester (7 months ago)

Etchell's tour and write-up of the Sigma factory is excellent. I'm very impressed with my Sigma lens and after seeing the complex and time consuming manufacturing process I'm surprised Sigma lenses don't cost more, a lot more.

Comment edited 38 seconds after posting
2 upvotes
nofumble
By nofumble (7 months ago)

Well, Japanese business model is to produce high quality at high volume. The country has no natural resource. Their only resource is the people and their skills. If they charge too much for their product like the Germans do, fewer people can afford and fewer Japanese can find employment.

It is no different from an Apple product, or any electronics product.

But I am afraid their cost will increase if they can't find a renewable energy source to replace nuclear though.

2 upvotes
parkmcgraw
By parkmcgraw (7 months ago)

1 of 2

Hello BlueJakester

The number of non qualified and erroneous comments on this site are almost never ending.

The contamination control procedures at Sigma look anything but disciplined or professional, instead appearing to be run by amateur managers pretending to have been formally trained in the field, faking it.

The staff in cleanroom "bunny" suits more for visual effect to impress the unknowing, as the staff at Sigma are improperly gown (female in coating lab, female using interferometer, female inspecting lens, two men standing next to possible ESD station) with individuals not wearing gloves, sleeves not properly pulled down exposing skin surface and very high particle shedding surface.

Seeing the cleanroom procedures being as they are suspect the lab's ESD procedures require scrutiny as well.

Comment edited 4 minutes after posting
1 upvote
parkmcgraw
By parkmcgraw (7 months ago)

2 of 2

I would then immediately review and shut down all lab operations, remove the process engineer and lab managers, produce new training material and retrain the cleanroom staff, all prior to restarting lab operations.

My qualifications, I wrote many of the ESD, and cleanroom procedures for ISO 3-8 (FED STD 209E 1-100,000) at the Laser and Sensor Products Center at Northrop Grumman as the Process Engineering Manager, and Member of the Technical Staff, today the de facto base document for the entire Aerospace Systems sector.

----------------

Do a job, big or small, do it right, or not at all.

----------------

Yamakisan (Sigma CEO)

Omae wa! Wakata desu ka.

Comment edited 6 times, last edit 13 minutes after posting
2 upvotes
ZiggyDeath
By ZiggyDeath (7 months ago)

Yes, because they're clearly making stuff that requires such tight tolerances.

3 upvotes
SRT3lkt
By SRT3lkt (7 months ago)

If this is what they do to High School Students, it is scary to imagine what they are doing to adult workers in closed environment.

https://www.youtube.com/watch?v=WlpNLR_IbdQ

almost human rights violation though... I hope they are making quality lenses in “humanely” manner.

0 upvotes
chuck1856
By chuck1856 (7 months ago)

It's almost certainly a white room, not a certified clean room. But surely an industry veteran would recognize that at first glance?

0 upvotes
SRT3lkt
By SRT3lkt (7 months ago)

Japanese has extremely high standard of QA.

www.youtube.com/watch?v=-leHJ6t4kiY

sharpness comes from discipline!

2 upvotes
parkmcgraw
By parkmcgraw (7 months ago)

Please read my posting above.

0 upvotes
AlpCns2
By AlpCns2 (7 months ago)

parkmcgraw: no thank you. I read your other posts too. You're a troll, not a "scientist" who "wrote the book".

2 upvotes
pwmoree
By pwmoree (7 months ago)

Amazing read. We are lucky to be able to buy these lenses at such reasonable prices. Very good item, a must read indeed.

3 upvotes
yabokkie
By yabokkie (7 months ago)

expect lower prices for Japanese have been devaluating yen (lost near 30% in one year), are going to raise consumption tax for lower corporation tax, and make it easier for companies to fire employees ...

0 upvotes
3dreal
By 3dreal (7 months ago)

It IS possible to produce best possible series of lenses. Zeiss are currently proving it with its coming HQ lenses. They will beat every currently FF lens.

2 upvotes
groucher
By groucher (7 months ago)

If Zeiss ever manage to beat 20 year old Nikon prime glass, they will be doing an amazing job.

0 upvotes
Murmillo
By Murmillo (7 months ago)

groucher, most (not all but most) of Nikon's 20 year old's BEST prime glass is soundly beaten to a pulp, flattened, chopped into small boxes by some of the newer lens designs.
Disclaimer: I have loads of the old Nikkor classics & love them nonetheless, including the (unbeaten IMO) Noct.

2 upvotes
groucher
By groucher (7 months ago)

I detect a hint of exaggeration there. I'm not saying that the new stuff isn't great - just that many of the old lenses will do the job just as well at lower cost.

1 upvote
Silvarum
By Silvarum (7 months ago)

Maybe Zeiss just have very strict QA and throws away most of the lenses. That's one reason for high price I guess.

0 upvotes
Ralf B
By Ralf B (7 months ago)

... and thinking of DPR's future, how come I find more and more sources of good digital photography elsewhere compared to 8 years ago? A lens rental site disclosing the quality assurance process they run on their lens stock makes for a better read than found on this site here for quite some time!
Diversity isn't the only key to survival, Simon. Remember where this site came from...so hats off for the courage to actually link to the good stuff over at IR and Lens Rental. A good service to your web site visitors (= customers)!

In that context: Thanks for NOT linking to rumor sites, that "service" is taken care of by forum rumor mongers to an over-saturating degree :-(

4 upvotes
Ralf B
By Ralf B (7 months ago)

Hats off to Dave! Reading his post made me feel like having been there myself.
Now give him and Simon Joinson some more sake and let them negotiate a joint venture of IR and DPR ...

Comment edited 2 times, last edit 2 minutes after posting
1 upvote
Ronan_M
By Ronan_M (7 months ago)

After watching the tour of the factory and knowing about the processes and precision that they (and others too) need to abide by, I kind of wonder why a 16 element 2.8 ED etc piece of optical precision glass can cost 400$ and a pair of Gucci or Rayban sunglasses with a SINGLE piece of UV-protected plastic can cost the same?

4 upvotes
groucher
By groucher (7 months ago)

Probably because the Gucci or Rayban label costs $399 to produce.

9 upvotes
Murmillo
By Murmillo (7 months ago)

Groucher hit the proverbial nail on the head :-)

2 upvotes
misha marinsky4
By misha marinsky4 (7 months ago)

"a pair of Gucci or Rayban sunglasses with a SINGLE piece of UV-protected plastic can cost the same?"

I worked as a licensed optician for 22 years. Those sunglasses cost ~US $30.00 to manufacture. People are willing to pay that so they can have RayBan to show off.

2 upvotes
Smalldane50
By Smalldane50 (7 months ago)

Impressive to see. Nice article.

1 upvote
peevee1
By peevee1 (7 months ago)

Great inside what really goes into a lens cost. Yes, it is
- expensive optical glass ~proportionally to its weight
- polishing of the sufrace - proportionally to surface areas of the lenses
- coating - ~proportionally to surface areas of the lenses
- assembly - ~proportionally to number of elements

Smaller, lighter lenses are also cheaper to make - don't fool yourself thinking otherwise.

1 upvote
peevee1
By peevee1 (7 months ago)

Sheesh, "insight".

0 upvotes
Plastek
By Plastek (7 months ago)

peevee1 - you forgot about one thing: Higher precision = higher price.
So if you want really high quality lens that's small at the same time (for example - because it's used on a small size sensor like m4/3) than it's price will be higher.
That's why all these 50s are cheaper on DSLRs than CSCs - noone cares much about small size and the sensor is large, so you can allow yourself some more... freedom in manufacturing in order to pull the price down.

1 upvote
Karroly
By Karroly (7 months ago)

"Smaller, lighter lenses are also cheaper to make - don't fool yourself thinking otherwise."
I am afraid it is not that simple. Smaller lenses for smaller sensors require higher tolerances and precision just because the elements that move when focusing/zooming have a much shorter range. Usually, shrinking an object by ten needs the absolute tolerance to be divided by ten. If you manufacture a lens with a 1 micron tolerance, then a lens ten times smaller would require a 0.1 micron tolerance at least.

1 upvote
imsabbel
By imsabbel (7 months ago)

Sorry, but thats kinda bull.

Polishing cost goes up exponentially if you go aspheric.
And cost is proportinal to weigth... and material.

Now there is no magic way to get small and light lenses, al otherl things equal - you do this by using fluoride glass, aspheric elements and more tricky design - which cost more money.

1 upvote
Mr Fartleberry
By Mr Fartleberry (7 months ago)

I want to believe ... but the fact is no one is abandoning their Canikony lense in any class to use the Sigma. Unless they're a shill like I've seen in the Canadian photo press.

Nothing against Sigma but your past history follows you around. It's just not a simple case of throwing your shittty underwear in the wash with a sheet of Bounce and think you'll come out smelling like .... mountain meadow.

3 upvotes
unknown member
By (unknown member) (7 months ago)

You are living way in the past. Sigma in no way resembles the company it once was, and that has been the case for many years now.

Just look at the build quality of Sigma's cameras, for example. They are top notch and as good as anything out there. Then consider the truly revolutionary picture quality their cameras are capable of. They are the only camera maker that has done anything truly significant to increase image quality.

Finally, is it really necessary to use disgusting toilet metaphors to make your point?

0 upvotes
chlamchowder
By chlamchowder (7 months ago)

"past history follows you around"....
I think Sigma right now is an excellent example of how a company can turn around from a bad reputation by doing an exceptional job. They're not just making lower quality, cheaper versions of common lenses anymore. Recently, they've put out:
-18-35/1.8: no other manufacturer has a f/1.8 zoom
-35/1.4: as good as (or better than) first party versions for a lower price
-USB dock: adjust lenses without having to ship them off
And that adds to their already strong portfolio with lenses like the 120-300/2.8 (no one else has a 300/2.8 that zooms back)
In terms of lenses, Sigma right now is on track to beating first party manufacturers at their own game. If they continue to play it right, Sigma could come out smelling like mountain meadow.

7 upvotes
Ronan_M
By Ronan_M (7 months ago)

Im VERY happy with both my Sigma lenses....cant say the same thing about the Tamron though

0 upvotes
Plastek
By Plastek (7 months ago)

Well, I don't know - all Tamron lenses I got are there only because Sigma has even worse products.
There are right now only 4 outstanding lenses from Sigma. They're still long way from beating crap out of Tamron. And most likely - till than Tamron will catch up and beat them again.

Though definitely - Sigma knows where's a warm spot in Photographers soul and right now - that's where they're aiming. With a great success as you can see from chlamchowder's post.

0 upvotes
Stacey_K
By Stacey_K (7 months ago)

I just replaced my 16-85VR nikon lens with a sigma 17-70OS. So yes I did abandon my OE lens for a 3rd party one because it's a better lens!

0 upvotes
Ernest M Aquilio
By Ernest M Aquilio (7 months ago)

The Sigma 35mm and 50mm are on my camera 90% of the time. They are truly great lenses.

3 upvotes
Ferling
By Ferling (7 months ago)

In my days of engineering and working with molding, extrusion and tooling of materials, even though it was Medical devices, I can relate to much of the article. A hand made prototype could prove a great design. Then came the real hard part: repeatability in an automated process. Which involved a different team of engineers and technicians skilled in the art.

Hopefully this article sheds some light on why a good Quality Assurance department can make the difference in a respected product. That if you do get a lemon, just exchange it for another. It happens.

1 upvote
KariIceland
By KariIceland (7 months ago)

I think that applies to all manufacturing, i worked for nine years in commercial printing,
We made carton boxes of all shapes and sizes for companies, from boxes for fake limbs down to small candy boxes, cereal boxes and so on, many designs look good on paper but the machinery cant handle everything.
issues that can come up are "width of the box vs height" to long and narrow it wont go through properly (we did a ton of DIY to fix so many issues),
the thickness of the carton (to thin it would rip, to thick it would refuse to go through)
The color used (if it was to wet or the wrong color used it would smudge all over and be ruined),
what kind of coating is on the carton? (if the coating was not good enough we had to use another type of glue)

And so many things could go wrong because of the designs and so many did, we however rarely had to turn down a job.

2 upvotes
Ferling
By Ferling (7 months ago)

I agree. A few times we had to go back and redesign or deal with material change issues in the original design that would help facilitate mass production. With medical devices, there was a zero tolerance for any failure, (for obvious reasons). So changes were not based on making it cheaper, but making it safer to mass produce and thus reduce error rates.

It was tedious work, with design cycles up to five years. Company employees whom were hospitalized would request that doctors use our products because they knew how safe they were. That's real pride.

0 upvotes
Model Mike
By Model Mike (7 months ago)

Fascinating, splendidly written article. Go, Sigma!

3 upvotes
snegron2
By snegron2 (7 months ago)

Very cool article! While I am a long time Nikon fan (only Sigma experience was with an old 100-300 I didn't care much for), I am willing to give Sigma another try after reading this article.

2 upvotes
four under
By four under (7 months ago)

There was a time I wouldn't have taken a Sigma lens for a gift. Those days are long gone though, they have some great products now.

8 upvotes
InTheMist
By InTheMist (7 months ago)

That was a great read. Sigma - shaking it up!

2 upvotes
Gesture
By Gesture (7 months ago)

What about the cameras?

0 upvotes
unknown member
By (unknown member) (7 months ago)

I own two of them, the DP 1 and 2 Merrill series cameras. No matter how many pictures I take I am truly stunned every time I develop a raw image from them. No other camera and lens has done that for me. Staggering picture detail and quality. They just need to make the Foveon sensors more sensitive to improve high ISO performance.

4 upvotes
Plastek
By Plastek (7 months ago)

I think more important would be to drive the price down than getting better high ISO - I would buy a great low-ISO camera in an instant, but not for these prices.

0 upvotes
unknown member
By (unknown member) (7 months ago)

"I think more important would be to drive the price down than getting better high ISO - I would buy a great low-ISO camera in an instant, but not for these prices."

The prices are more than reasonable. Whether you can afford them is a different matter. No disrespect intended.

1 upvote
MPA1
By MPA1 (7 months ago)

Never been a big fan of Sigma lenses, or any of the third party makers to be honest.
My Nikkors have always seemed better built and drawn nicer images.

0 upvotes
Gesture
By Gesture (7 months ago)

Some of our OEM lenses are made by the third party manufacturers and the OEMs have sold third party designs as "their own." I wouldn't thrown Tokina, Tamron and Sigma under the bus.

9 upvotes
unknown member
By (unknown member) (7 months ago)

Yep, the best of Sigma, Tokina and Tamron lenses are as well built as anything out there. The best built and finished lens I ever owned was a Tokina ATX lens. It was also the sharpest.

All major camera and lens manufacturers make lenses of varying quality, both in build and image quality. The cheapest built lenses I have owned were Canon. The cheapest of the Nikons look no different.

3 upvotes
Pritzl
By Pritzl (7 months ago)

Sigma is now testing every single lens? That's one impressive statement of intent.

4 upvotes
unknown member
By (unknown member) (7 months ago)

Basically they have to to take advantage of the super sharp Foveon sensors.

2 upvotes
AbrasiveReducer
By AbrasiveReducer (7 months ago)

Good info and glad they didn't stick you with the dinner bill. The part about them rejecting a lot of lenses that don't quite measure up was very interesting because with so much automation, I'm sure it's tempting to give everything a pass.

1 upvote
Gesture
By Gesture (7 months ago)

Neat stuff. Looks high-tech and old school. We all remember grinding a telescope mirror as kids. Fantastic article by Dave and kudos to DPReview for linking it.

Comment edited 12 minutes after posting
3 upvotes
MPA1
By MPA1 (7 months ago)

"We all remember grinding a telescope mirror as kids?!"

I most certainly don't. I've never even seen a telescope mirror except on TV, much less ground one.

7 upvotes
Roland Karlsson
By Roland Karlsson (7 months ago)

Agree!! I have never done it either. Had some plans though. Would have been fun to look at Jupiter with the help of a home made mirror :)

1 upvote
unknown member
By (unknown member) (7 months ago)

"I most certainly don't. I've never even seen a telescope mirror except on TV, much less ground one."

Maybe you're too young? There used to be a time when science experiment kits used to be sold so kids could do a lot of things that our upside down world today no longer allows. The 70s were the peak for such things. Now you can't even get a decent toy in a Cracker Jacks box for fear of some idiot giving their child something to choke on.

4 upvotes
Mark Roberts
By Mark Roberts (7 months ago)

What a great report... I was delighted to see it written with a human perspective, not just technical.

5 upvotes
Braxton7
By Braxton7 (7 months ago)

The Dave Etchell piece was very interesting. I read and enjoyed the whole thing. Much better than those superficial u-tube things we get everywhere now.

5 upvotes
Devendra
By Devendra (7 months ago)

i also liked the last part.. when it ended with sushi!

5 upvotes
yabokkie
By yabokkie (7 months ago)

a good footnote to the relationship between lens price and aperture area (surface area of all lens elements here).

0 upvotes
OpticsEngineer
By OpticsEngineer (7 months ago)

A very comprehensive and well written exposition. Well worth reading.

2 upvotes
Scorpius1
By Scorpius1 (7 months ago)

Sigma is a company in ascension,and It's nice to witness someone shaking up the Japanese paradigm ..

12 upvotes
Total comments: 99