Sigma highlights another problem with plastics, thermal change

In article
,
RichA wrote:

Heat expansion and contraction, which effects optical performance. So
they've introduced something else to compensate for it. Because
aluminum and magnesium don't suffer nearly as much thermally-related
shape changes as plastic, older lenses and new high-end principally
metal lenses do not have the problem.

Sigma's biggest problem is their lying about the crappy technology used
in their overpriced, mediocre equipment.

On 2012-06-17 11:46 , Mr. Strat wrote:
In article
,
RichA wrote:

Heat expansion and contraction, which effects optical performance. So
they've introduced something else to compensate for it. Because
aluminum and magnesium don't suffer nearly as much thermally-related
shape changes as plastic, older lenses and new high-end principally
metal lenses do not have the problem.

Sigma's biggest problem is their lying about the crappy technology used
in their overpriced, mediocre equipment.

Sigma does produce a few very good lenses.

In particular the FF 180mm f/3.5 (1:1) macro gives stellar results while
also providing good standoff distance (doesn't frighten the subject or
obstruct as much light as 100 or 50mm macros).

They've introduced an f/2.8 version recently. I don't know how well it
performs - but I'd bet it's every bit as good as the f/3.5.


--
"Civilization is the limitless multiplication of unnecessary necessities."
-Samuel Clemens.

In article , Alan Browne
wrote:

Sigma's biggest problem is their lying about the crappy technology used
in their overpriced, mediocre equipment.

Sigma does produce a few very good lenses.

if you luck out and get a good one, yes, but unfortunately, their
quality control is all over the map and it might take several copies to
do that.

In particular the FF 180mm f/3.5 (1:1) macro gives stellar results while
also providing good standoff distance (doesn't frighten the subject or
obstruct as much light as 100 or 50mm macros).

the tamron 180mm is a far more reliable choice than the sigma 180,
following in the footsteps of the tamron 90mm, which is one of the best
macro lenses made.

On 2012-06-17 14:55 , nospam wrote:
In article , Alan Browne
wrote:

Sigma's biggest problem is their lying about the crappy technology used
in their overpriced, mediocre equipment.

Sigma does produce a few very good lenses.

if you luck out and get a good one, yes, but unfortunately, their
quality control is all over the map and it might take several copies to
do that.

In particular the FF 180mm f/3.5 (1:1) macro gives stellar results while
also providing good standoff distance (doesn't frighten the subject or
obstruct as much light as 100 or 50mm macros).

the tamron 180mm is a far more reliable choice than the sigma 180,
following in the footsteps of the tamron 90mm, which is one of the best
macro lenses made.

Since I have DIRECT knowledge of the Sigma in question I know there are
no doubts as to its quality - build and esp. in light of the images it
produces. A friend (who photographs more than most people) has had the
"film era" f/3.5 version for over 10 years and continues to put it to
great use. I'll take his experience and photos over net lore.

--
"Civilization is the limitless multiplication of unnecessary necessities."
-Samuel Clemens.

Alan Browne wrote:
On 2012-06-17 14:55 , nospam wrote:
In article , Alan Browne


Sigma does produce a few very good lenses.

if you luck out and get a good one, yes, but unfortunately, their
quality control is all over the map and it might take several copies to
do that.

In particular the FF 180mm f/3.5 (1:1) macro gives stellar results while

the tamron 180mm is a far more reliable choice than the sigma 180,

Since I have DIRECT knowledge of the Sigma in question I know there are
no doubts as to its quality - build and esp. in light of the images it
produces. A friend (who photographs more than most people) has had the
"film era" f/3.5 version for over 10 years and continues to put it to
great use. I'll take his experience and photos over net lore.

Doesn't say much about problems with QC. You two 'lucked out'
and got a good copy. Noone says Sigma cannot build good lenses
--- only that they don't do that consistently enough for comfort.

-Wolfgang

On Wed, 20 Jun 2012 11:27:56 +0200, Wolfgang Weisselberg
wrote:
: Alan Browne wrote:
: On 2012-06-17 14:55 , nospam wrote:
: In article , Alan Browne
:
:
: Sigma does produce a few very good lenses.
:
: if you luck out and get a good one, yes, but unfortunately, their
: quality control is all over the map and it might take several copies to
: do that.
:
: In particular the FF 180mm f/3.5 (1:1) macro gives stellar results while
:
: the tamron 180mm is a far more reliable choice than the sigma 180,
:
: Since I have DIRECT knowledge of the Sigma in question I know there are
: no doubts as to its quality - build and esp. in light of the images it
: produces. A friend (who photographs more than most people) has had the
: "film era" f/3.5 version for over 10 years and continues to put it to
: great use. I'll take his experience and photos over net lore.
:
: Doesn't say much about problems with QC. You two 'lucked out'
: and got a good copy. Noone says Sigma cannot build good lenses
: --- only that they don't do that consistently enough for comfort.

How many Sigma lenses have you ever owned, Wolfgang? How good were they?

Bob

Wolfgang Weisselberg writes:

Alan Browne wrote:
On 2012-06-17 14:55 , nospam wrote:
In article , Alan Browne


Sigma does produce a few very good lenses.

if you luck out and get a good one, yes, but unfortunately, their
quality control is all over the map and it might take several copies to
do that.

In particular the FF 180mm f/3.5 (1:1) macro gives stellar results while

the tamron 180mm is a far more reliable choice than the sigma 180,

Since I have DIRECT knowledge of the Sigma in question I know there are
no doubts as to its quality - build and esp. in light of the images it
produces. A friend (who photographs more than most people) has had the
"film era" f/3.5 version for over 10 years and continues to put it to
great use. I'll take his experience and photos over net lore.

Doesn't say much about problems with QC. You two 'lucked out'
and got a good copy. Noone says Sigma cannot build good lenses
--- only that they don't do that consistently enough for comfort.

My three Sigma lenses have all been good copies as well.

--
David Dyer-Bennet, ; http://dd-b.net/
Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/
Photos: http://dd-b.net/photography/gallery/
Dragaera: http://dragaera.info