The multi-element, spherical lens-based lens MUST DIE!!

RichA wrote:
On Mar 3, 1:30 am, Paul wrote:
RichA wrote:
They must eliminate the multi-element lens. It is too heavy. It is
too complex inside therefore TOO expensive. 14-17 elements? Why, in
this day of hybrid aspherics and ED glass? Pentax makes a 400mm f4
telescope with 4 elements that produces a highly-corrected (colour,
astigmatism, spherical aberration) FLAT image across an entire medium
format film plane. With FOUR elements! WHERE is the Nikon or Canon
lens that can do that with so few elements? For about $3k. Takahashi
(Japanese) has a similar lens. And those lenses do it diffraction-
limited without stopping down! Multi-element lens systems based on
spherical lenses are DINOSAURS.

How do they do at close focus/macro distances?

You can focus them as close as you want, with extender adapters.
However, a lens optimized for infinity is going to have spherical
aberration close up. In that case you will have to stop them down.

OK so they don't work for stuff like birds filling the frame, the sort
of thing people would buy a 400mm prime for in terrestrial photography.


Fast autofocus?

Big deal. It's like Canon and Nikon almost doubling lens prices for
including I.S./V.R when other mfgs build it into the body of their
cameras. MONEY!!!

And camera body size.


Barrel/pincushion?

Generally almost none.

Even at close focus?


Compact?

The Takahashi and Pentax 400mm are slightly longer than say a Nikon
lens, but by avoiding a severely curved negative element (as the Nikon
needs to achieve that f.l. in a slightly smaller package) the optics
can be made to a considerably higher standard for less cost.

If they are telephoto designs, I believe that means more elements and
more compact. Non-telephoto designs are huge.

In rec.photo.digital Paul Furman wrote:

The Takahashi and Pentax 400mm are slightly longer than say a Nikon
lens, but by avoiding a severely curved negative element (as the Nikon
needs to achieve that f.l. in a slightly smaller package) the optics
can be made to a considerably higher standard for less cost.

If they are telephoto designs, I believe that means more elements and
more compact. Non-telephoto designs are huge.

Or catadioptric.

--
Chris Malcolm

Alfred Molon wrote:
In articlejrWdnTXwLqDqVvLQnZ2dnUVZ5uudnZ2d@giganews. com, Paul Furman
says...
Big deal. It's like Canon and Nikon almost doubling lens prices for
including I.S./V.R when other mfgs build it into the body of their
cameras. MONEY!!!

And camera body size.

There are several DSLR and EVIL bodies with in-body IS which are quite
compact.

Oops, I was thinking focus motor in the body.

On 4/03/2011 4:53 PM, Paul Furman wrote:
Alfred Molon wrote:
In articlejrWdnTXwLqDqVvLQnZ2dnUVZ5uudnZ2d@giganews. com, Paul Furman
says...
Big deal. It's like Canon and Nikon almost doubling lens prices for
including I.S./V.R when other mfgs build it into the body of their
cameras. MONEY!!!

And camera body size.

There are several DSLR and EVIL bodies with in-body IS which are quite
compact.

Oops, I was thinking focus motor in the body.

Most of the Pentax DSLR camera bodies have in-body IS (with APS sensor)
and aren't any bigger that the FourThirds DSLR bodies.