Sigma highlights another problem with plastics, thermal change

In article , Robert Coe
wrote:

: it's very simple: a company that buys zillions of lenses of all makes
: is in the best position to say which ones fail the most.

"Zillions?" A couple of days ago it was only "thousands". I'd guess that
"hundreds" is a more accurate description, but who's really counting?

it looks like you're counting.

: someone who buys a few lenses does not have enough of a sample size to
: make any conclusions, especially if they didn't do any formal testing.

Exactly what I've been saying about you!

in other words, how many sigma lenses i bought is irrelevant. you're
catching on.

Keep in mind that I don't contradict
your opinion of Sigma's QA.

then what are you doing?

I just don't believe that you can back that
opinion up with facts.

except i already have.

So I'll ask you again: What has been your first-hand experience with Sigma
lenses?

suffice it to say that i have had first-hand experience.

If I'm wrong (that you've had none), provide the correct answer. We'll all
believe you. To your credit and Wolfgang's, you both seem unwilling to
actually lie about it.

baseless accusation. i'm not lying and nothing i said is false.

I don't have any axe to grind for Sigma. I just think that the opinions you
and Wolfgang have been throwing out are based largely on hearsay of
questionable reliability. This is your chance to set me straight.

of course you think the evidence is questionable, because you have 4
sigma lenses and realizing that you might have duds is not a pleasant
thought. even if they're ok now, who knows what will happen in a year
or two.

Wolfgang Weisselberg wrote:

Fine that you agree that first-hand experience is unable to say
much about nation-wide death numbers due to traffic accidents and
likewise unable to say much about Sigma's QA. The sample set is
way to small that way, be it 1 or 2 or 4 or 8 lenses.

If as was claimed more than half Sigma's lenses are bad, then a random
sample (e.g. me and friends) of 8 Sigma lenses which are ok is
probabilistically better than 8 heads in a row when spinning a
coin. That's enough to make one wonder whether there is some trickery
going on, enough to make one question whether the original claim about
Sigma unreliability and inconsistency was correct. Not enough to
refute it of course. It's possible to spin 8 heads in a row by lucky
chance. Just pretty unlikely.

--
Chris Malcolm

"Chris Malcolm" wrote in message ...

Wolfgang Weisselberg wrote:

Fine that you agree that first-hand experience is unable to say
much about nation-wide death numbers due to traffic accidents and
likewise unable to say much about Sigma's QA. The sample set is
way to small that way, be it 1 or 2 or 4 or 8 lenses.

If as was claimed more than half Sigma's lenses are bad, then a random
sample (e.g. me and friends) of 8 Sigma lenses which are ok is
probabilistically better than 8 heads in a row when spinning a
coin.


Toss in the four good Sigma lenses here, and we have a true miracle. ROFL.

Sigma makes some great niche lenses (12-24, fast wide-angle primes) and some
great macro lenses. All of these stand up to the nastiest of pixel-peeping
just fine. Dunno about the cheap consumer lenses, but cheap Nikon and Canon
lenses are pretty crappy, so you get what you pay for.


That's enough to make one wonder whether there is some trickery
going on, enough to make one question whether the original claim about
Sigma unreliability and inconsistency was correct. Not enough to
refute it of course. It's possible to spin 8 heads in a row by lucky
chance. Just pretty unlikely.


Yep. It sounds much more that the lens rental place had a beef with Sigma
policies of some sort, e.g. not giving them as much of a discount as they
wanted.

-- David J. Littleboy
Tokyo, Japan

Chris Malcolm wrote:
Wolfgang Weisselberg wrote:

Fine that you agree that first-hand experience is unable to say
much about nation-wide death numbers due to traffic accidents and
likewise unable to say much about Sigma's QA. The sample set is
way to small that way, be it 1 or 2 or 4 or 8 lenses.

If as was claimed more than half Sigma's lenses are bad,

Who claimed that where? URL/Message ID, please.
And was the claim for *all* of Sigma's lenses or for some
*specific* models of Sigma's lenses? Was the claim for well used
lenses or out of the box?

then a random
sample (e.g. me and friends)

Sure, after checking and exchanging the bad (or not well
matched to the camera) lenses the sample is still random.
As is the sample when both the troublesome and the OK lens
models are mixed in.

You don't even know if your dealers did a quick post-Sigma check
to avert angry customers, further "randomizing" your sample.


of 8 Sigma lenses which are ok is
probabilistically better than 8 heads in a row when spinning a
coin.

That's enough to make one wonder whether there is some trickery
going on, enough to make one question whether the original claim about
Sigma unreliability and inconsistency was correct. Not enough to
refute it of course. It's possible to spin 8 heads in a row by lucky
chance. Just pretty unlikely.

Well, the trickery is all on your side in this example.

-Wolfgang

In article , Chris Malcolm
wrote:

If as was claimed more than half Sigma's lenses are bad, then a random
sample (e.g. me and friends) of 8 Sigma lenses which are ok is
probabilistically better than 8 heads in a row when spinning a
coin. That's enough to make one wonder whether there is some trickery
going on, enough to make one question whether the original claim about
Sigma unreliability and inconsistency was correct. Not enough to
refute it of course. It's possible to spin 8 heads in a row by lucky
chance. Just pretty unlikely.

how did you test them?

In article , David J.
Littleboy wrote:

Sigma makes some great niche lenses (12-24, fast wide-angle primes) and some
great macro lenses. All of these stand up to the nastiest of pixel-peeping
just fine.

not really
http://www.16-9.net/lens_tests/nikon_14_24mm_1/nikon14_24mm_a.html

in particular,
http://www.16-9.net/lens_tests/nikon_14_24mm_1/sig1224_24mm_f56_zc.jpg
http://www.16-9.net/lens_tests/nikon_14_24mm_1/nik1424_24mm_f5_zc.jpg

http://www.16-9.net/lens_tests/nikon_14_24mm_1/sig1424_14mm_f56_zc2.jpg
http://www.16-9.net/lens_tests/nikon_14_24mm_1/nik1424_14mm_f5_zc2.jpg


Yep. It sounds much more that the lens rental place had a beef with Sigma
policies of some sort, e.g. not giving them as much of a discount as they
wanted.

except that their findings are consistent with countless threads on
dpreview and many other forums where people get problematic sigma
lenses.

On Mon, 02 Jul 2012 08:06:01 -0700, nospam wrote:
: In article , David J.
: Littleboy wrote:
:
: Sigma makes some great niche lenses (12-24, fast wide-angle primes) and some
: great macro lenses. All of these stand up to the nastiest of pixel-peeping
: just fine.
:
: not really
: http://www.16-9.net/lens_tests/nikon_14_24mm_1/nikon14_24mm_a.html
:
: in particular,
: http://www.16-9.net/lens_tests/nikon_14_24mm_1/sig1224_24mm_f56_zc.jpg
: http://www.16-9.net/lens_tests/nikon_14_24mm_1/nik1424_24mm_f5_zc.jpg
:
: http://www.16-9.net/lens_tests/nikon_14_24mm_1/sig1424_14mm_f56_zc2.jpg
: http://www.16-9.net/lens_tests/nikon_14_24mm_1/nik1424_14mm_f5_zc2.jpg
:
:
: Yep. It sounds much more that the lens rental place had a beef with Sigma
: policies of some sort, e.g. not giving them as much of a discount as they
: wanted.
:
: except that their findings are consistent with countless threads on
: dpreview and many other forums where people get problematic sigma
: lenses.

Most of the "countless threads" I've seen refer back to the Lensrentals
diatribe. But if the circularity doesn't bother you, so be it.

Bob

On Mon, 02 Jul 2012 08:05:58 -0700, nospam wrote:
: In article , Chris Malcolm
: wrote:
:
: If as was claimed more than half Sigma's lenses are bad, then a random
: sample (e.g. me and friends) of 8 Sigma lenses which are ok is
: probabilistically better than 8 heads in a row when spinning a
: coin. That's enough to make one wonder whether there is some trickery
: going on, enough to make one question whether the original claim about
: Sigma unreliability and inconsistency was correct. Not enough to
: refute it of course. It's possible to spin 8 heads in a row by lucky
: chance. Just pretty unlikely.
:
: how did you test them?

Coming from you, that is beyond hilarious. :^)

Bob

"nospam" wrote in message ...

In article , David J.
Littleboy wrote:

Sigma makes some great niche lenses (12-24, fast wide-angle primes) and
some
great macro lenses. All of these stand up to the nastiest of pixel-peeping
just fine.

not really
http://www.16-9.net/lens_tests/nikon_14_24mm_1/nikon14_24mm_a.html


Really. That lens is crap at 12mm. (Which is a real issue: 12 is a
noticeable improvement over 14 for cramped interiors and dizzy fun.) And
it's seriously pricey and grossly inconvenient to use on Canon. And not as
good as the Zeiss 21 at 21, which actually can use filters.

-- David J. Littleboy
Tokyo, Japan

In article , Robert Coe
wrote:

: Yep. It sounds much more that the lens rental place had a beef with Sigma
: policies of some sort, e.g. not giving them as much of a discount as they
: wanted.
:
: except that their findings are consistent with countless threads on
: dpreview and many other forums where people get problematic sigma
: lenses.

Most of the "countless threads" I've seen refer back to the Lensrentals
diatribe. But if the circularity doesn't bother you, so be it.

actually they don't. most are personal experiences of the posters. but
if the facts aren't of interest to you, so be it.