"Super Zoom" Cameras

With these devices now having reached 65x optical zoom (35mm
equivalent), where will it end? What's the practical limit? Will 100x
ever be achieved?

Discuss, please!

John

On 2014-11-13 20:57:14 +0000, John Turco said:

With these devices now having reached 65x optical zoom (35mm
equivalent), where will it end? What's the practical limit? Will 100x
ever be achieved?

Discuss, please!

John

The old resident expert on these things seems to have dropped off the
planet, and all of us are thankful for that.

--
Regards,

Savageduck

On 13/11/2014 20:57, John Turco wrote:

With these devices now having reached 65x optical zoom (35mm
equivalent), where will it end? What's the practical limit? Will 100x
ever be achieved?

Diffraction limits and geometric abberations. The extra degrees of
freedom offered by being able to rescale the RGB images have allowed
things to progress well beyond the old heuristic of 3-4x optical zoom.

I am sure the marketing men will push for ever larger numbers now that
they have pretty much maxed out the pixel count.

Discuss, please!

John

IMHO anything above 10x is empty magnification at the high end and/or
distorted at the short end. The latter can be fiddled out in firmware.

Even if you have the real magnification it needs a very good tripod or
active stabilisation to use lenses with EFL 500mm on a 35mm camera.

--
Regards,
Martin Brown

On 2014-11-13 22:35:27 +0000, Martin Brown said:

On 13/11/2014 20:57, John Turco wrote:

Even if you have the real magnification it needs a very good tripod or
active stabilisation to use lenses with EFL 500mm on a 35mm camera.

Or imagers that are capable of higher and higher ISO speeds with
acceptable image quality. And they are getting better all the time.

On Thu, 13 Nov 2014 22:35:27 +0000, Martin Brown
wrote:

On 13/11/2014 20:57, John Turco wrote:

With these devices now having reached 65x optical zoom (35mm
equivalent), where will it end? What's the practical limit? Will 100x
ever be achieved?

Diffraction limits and geometric abberations. The extra degrees of
freedom offered by being able to rescale the RGB images have allowed
things to progress well beyond the old heuristic of 3-4x optical zoom.

I am sure the marketing men will push for ever larger numbers now that
they have pretty much maxed out the pixel count.

Discuss, please!

John

IMHO anything above 10x is empty magnification at the high end and/or
distorted at the short end. The latter can be fiddled out in firmware.

Even if you have the real magnification it needs a very good tripod or
active stabilisation to use lenses with EFL 500mm on a 35mm camera.


dumb guy question here, what do you mean by "rescale images"?

On 14/11/2014 02:12, charles wrote:
On Thu, 13 Nov 2014 22:35:27 +0000, Martin Brown
wrote:

On 13/11/2014 20:57, John Turco wrote:

With these devices now having reached 65x optical zoom (35mm
equivalent), where will it end? What's the practical limit? Will 100x
ever be achieved?

Diffraction limits and geometric abberations. The extra degrees of
freedom offered by being able to rescale the RGB images have allowed
things to progress well beyond the old heuristic of 3-4x optical zoom.

dumb guy question here, what do you mean by "rescale images"?

OK. On a traditional film camera you have to make the image with a lens
fully corrected for longitudinal and lateral chromatic abberation. That
is in good focus on the film plane and with the same magnification for
all wavelengths (or a close approximation to it). Usually exact at two
specific wavelengths or at three in the case of true APOs.

On a modern digital camera the lens designer has an additional degree of
freedom in that he only has to get the image properly in focus. The RGB
images can have slightly different magnifications and then be adjusted
later in the demosaic process to produce a final image.

You can't do that on film so it wasn't explored until fairly recently.
It would look terrible with rainbow fringes at the edge of frame.

Same with other geometric distortions like barrel and pincushion - they
can be compensated out in post processing by knowing the lens details.

--
Regards,
Martin Brown

Per John Turco:
What's the practical limit? Will 100x
ever be achieved?

I don't know much about photography, but I have a few IP cameras - one
of which does 32x zoom. http://ExtremeSurfCam.DynDNS.org "Toledo
Avenue".

My experience is that, at 32x, what I call "Atmospherics" comes in to
play. Don't know enough to discuss details, but the bottom line is that
on some days the image is pretty good and on other days the image is
close to useless.
--
Pete Cresswell

On Fri, 14 Nov 2014 13:43:10 +0000, Martin Brown
wrote:

On 14/11/2014 02:12, charles wrote:
On Thu, 13 Nov 2014 22:35:27 +0000, Martin Brown
wrote:

On 13/11/2014 20:57, John Turco wrote:

With these devices now having reached 65x optical zoom (35mm
equivalent), where will it end? What's the practical limit? Will 100x
ever be achieved?

Diffraction limits and geometric abberations. The extra degrees of
freedom offered by being able to rescale the RGB images have allowed
things to progress well beyond the old heuristic of 3-4x optical zoom.

dumb guy question here, what do you mean by "rescale images"?

OK. On a traditional film camera you have to make the image with a lens
fully corrected for longitudinal and lateral chromatic abberation. That
is in good focus on the film plane and with the same magnification for
all wavelengths (or a close approximation to it). Usually exact at two
specific wavelengths or at three in the case of true APOs.

On a modern digital camera the lens designer has an additional degree of
freedom in that he only has to get the image properly in focus. The RGB
images can have slightly different magnifications and then be adjusted
later in the demosaic process to produce a final image.

You can't do that on film so it wasn't explored until fairly recently.
It would look terrible with rainbow fringes at the edge of frame.

Same with other geometric distortions like barrel and pincushion - they
can be compensated out in post processing by knowing the lens details.


Ah, clear now. Thank you.

In article , says...

With these devices now having reached 65x optical zoom (35mm
equivalent), where will it end? What's the practical limit? Will 100x
ever be achieved?

Discuss, please!

John

http://www.fujifilmusa.com/products/...besm/#features

On 11/13/14 PDT, 2:02 PM, Savageduck wrote:
On 2014-11-13 20:57:14 +0000, John Turco said:

With these devices now having reached 65x optical zoom (35mm
equivalent), where will it end? What's the practical limit? Will 100x
ever be achieved?

Discuss, please!

John

The old resident expert on these things seems to have dropped off the
planet, and all of us are thankful for that.

Who, Steve Young??