Lens question

In article , android
says...

In article ,
Alfred Molon wrote:

Just curious - why do camera lenses contaian so many elements? Some
lenses have 17-20 elements. Is there a reason for that and wouldn't it
be possible or better to reduce the number of elements by using glass in
special shapes?

The better specs the more complicated the lense... The more complicated
the lense the harder it produce the elements as designed and to assemble
them in a proper manner. The Samy 14/2.8 is a good example there the
manufacturer seemed to have a design that could produce sharp but very
distorted images if you found yourself lucky in the sample lottery. I
was not.

Ok, so you are saying that it's a manufacturing issue. Special shapes
which would allow fewer elements in a lens too hard to make?
--
Alfred Molon

Olympus E-series DSLRs and micro 4/3 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
http://myolympus.org/ photo sharing site

In article , Alfred
Molon wrote:


Just curious - why do camera lenses contaian so many elements? Some
lenses have 17-20 elements. Is there a reason for that and wouldn't it
be possible or better to reduce the number of elements by using glass in
special shapes?

The better specs the more complicated the lense... The more complicated
the lense the harder it produce the elements as designed and to assemble
them in a proper manner. The Samy 14/2.8 is a good example there the
manufacturer seemed to have a design that could produce sharp but very
distorted images if you found yourself lucky in the sample lottery. I
was not.

Ok, so you are saying that it's a manufacturing issue.

the reason there are multiple elements is optics.

Special shapes
which would allow fewer elements in a lens too hard to make?

yes, which makes it expensive.

On Sun, 9 Apr 2017 23:05:09 +0200, Alfred Molon
wrote:

In article , android
says...

In article ,
Alfred Molon wrote:

Just curious - why do camera lenses contaian so many elements? Some
lenses have 17-20 elements. Is there a reason for that and wouldn't it
be possible or better to reduce the number of elements by using glass in
special shapes?

The better specs the more complicated the lense... The more complicated
the lense the harder it produce the elements as designed and to assemble
them in a proper manner. The Samy 14/2.8 is a good example there the
manufacturer seemed to have a design that could produce sharp but very
distorted images if you found yourself lucky in the sample lottery. I
was not.

Ok, so you are saying that it's a manufacturing issue. Special shapes
which would allow fewer elements in a lens too hard to make?

It's relatively eaasy to make lenses with precision spherical
surfaces, which is why they do it that way. Lenses with aspherical
(i.e. non-spherical) surfaces are much harder to make. That is one
reason why there are lenses with plastic elements which can be more
easily made in non spherical shapes.
--

Regards,

Eric Stevens

In article ,
Alfred Molon wrote:

In article , android
says...

In article ,
Alfred Molon wrote:

Just curious - why do camera lenses contaian so many elements? Some
lenses have 17-20 elements. Is there a reason for that and wouldn't it
be possible or better to reduce the number of elements by using glass in
special shapes?

The better specs the more complicated the lense... The more complicated
the lense the harder it produce the elements as designed and to assemble
them in a proper manner. The Samy 14/2.8 is a good example there the
manufacturer seemed to have a design that could produce sharp but very
distorted images if you found yourself lucky in the sample lottery. I
was not.

Ok, so you are saying that it's a manufacturing issue. Special shapes
which would allow fewer elements in a lens too hard to make?

You can drop forge plastic elements into weird shapes, they will not
have the the same optic quality but can be useful in special
applications. The problem with the Samy was that the assembly was sub
par.
--
teleportation kills