The myth of the "smaller" 4/3rds lens

Ron wrote:
I've heard rumors that Olympus will begin releasing smaller and lighter
lenses within the next year.

That is only by making lens surfaces more curved (to increase
magnification or reduce it more) in a given space. Also, extensive
and expensive use of ED and other exotic glasses helps allow this. But
people have to remember that lenses cannot "shrink" beyond a certain
point and it has NOTHING to do with sensor size. A 200mm f2 lens STILL
needs a 100mm wide front element to claim it is 200mm f2 (200/100 =
2). The REASON it seems that Olympus can make "smaller" lenses is
because a 200mm lens on a Full frame or 1.3-1.6 cropped sensor
provides a wider angle of view than the 2x Olympus that in-turn allows
Olympus to put more pixels into a given area of a scene, and resolve
more detail for a given lens focal length (provided both the Olympus
and the other brand have the same pixel count). So the proverbial
300mm lens on the 2x sensor functions like a 400mm lens on a FF
camera. The reciprocal being that you cannot get as wide a view with
an Olympus sensor as with a larger sensor because it would require
making lenses with shorter focal lengths. The shortest lens I've ever
seen was Nikon's 6mm which on a FF SLR has twice the field of view as
a 4/3rds camera.

But, if someone is thinking Olympus can produce a 300mm f2.8 lens any
smaller than Canon, they would be dead wrong. The lens STILL needs a
107mm of clear front aperture to meet it's speed claim.

There is ongoing research into ways to focus light for photographic use that
does not totally rely on glass/plastic as we know it particularly for use
with very small sensors.
The technology of imaging is evolving in ways that will not rely on
traditional materials just as digital sensors have replaced film for most
uses.
Bigger is not better even at this point in the development of digital
photography and will come to be seen as the liability it has always been
when better technical solutions become available.

bmoag wrote:

There is ongoing research into ways to focus light for photographic use that
does not totally rely on glass/plastic as we know it particularly for use
with very small sensors.
The technology of imaging is evolving in ways that will not rely on
traditional materials just as digital sensors have replaced film for most
uses.
Bigger is not better even at this point in the development of digital
photography and will come to be seen as the liability it has always been
when better technical solutions become available.


The flaw in this logic is number of photons. A smaller
camera with a smaller aperture lens collects fewer photons.
The signal-to-noise ratio in digital camera images is directly
related to the square root of the number of photons collected
in each pixel. Smaller pixels with smaller photons collected
also results in smaller dynamic range.

http://www.clarkvision.com/imagedeta...el.size.matter

Roger

bmoag wrote:
There is ongoing research into ways to focus light for photographic
use that does not totally rely on glass/plastic as we know it
particularly for use with very small sensors.
The technology of imaging is evolving in ways that will not rely on
traditional materials just as digital sensors have replaced film for
most uses.
Bigger is not better even at this point in the development of digital
photography and will come to be seen as the liability it has always
been when better technical solutions become available.

You can't simply "get smaller" without reaching a point that bumps up
against limitations rooted in the properties of light itself. Others here
have discussed this at length (Think Roger and David Littleboy).

--
Images (Plus Snaps & Grabs) by Mark² at:
www.pbase.com/markuson

RichA wrote:
Ron wrote:
I've heard rumors that Olympus will begin releasing smaller and lighter
lenses within the next year.

That is only by making lens surfaces more curved (to increase
magnification or reduce it more) in a given space. Also, extensive
and expensive use of ED and other exotic glasses helps allow this. But
people have to remember that lenses cannot "shrink" beyond a certain
point and it has NOTHING to do with sensor size.
Why would you make such a point of this.. and then go about telling us
the opposite? Of course sensor size makes a difference, *for a given
angle of view*! And if you don't hold the angle of view constant for
comparing whether a given camera/lens combination is bulkier than
another, then what is the point?? Yes, we know about sensor noise
issues, but this was about lens size/bulk.

A 200mm f2 lens STILL
needs a 100mm wide front element

Umm. Forgive my pickiness - I'm a bit rusty on lens design. But is it
the *front element* that gives the aperture calculation???? I mean I
realise it has to be a certain size to allow the lens to operate to
it's full 'f' capability, but isn't it the APERTURE that is used for
calculating the f-ratio? Ie the IRIS opening, not the front element.
I humbly apologise if I'm wrong, and I realise they are of course
related, but let's be *accurate* here...

The REASON it seems that Olympus can make "smaller" lenses is
because a 200mm lens on a Full frame or 1.3-1.6 cropped sensor
provides a wider angle of view than the 2x Olympus that in-turn allows
Olympus to put more pixels into a given area of a scene, and resolve
more detail for a given lens focal length

As per my initial comment - DUUUH!

So the proverbial
300mm lens on the 2x sensor functions like a 400mm lens on a FF
camera.

Am I missing something here as well? It's a 2x multiplication factor,
and yet Rich says a 300 goes to ..400? Umm, yeah right...

The shortest lens I've ever
seen was Nikon's 6mm
Sigh. Never looked at a video camera or a compact?

which on a FF SLR has twice the field of view as
a 4/3rds camera.

Err, say what? I missed the point of that line.. Yes, to match that
6mm lens, Oly would have to create a 3mm. Challenging? Yes indeed.
But how many 6mm (35 equiv) owners are there around here? (That 6mm
lens, if mounted on the Oly, would act like a 12mm (35 equiv) extreme
w/a, and I doubt *many* folks would be agonising that they couldn't go
wider...

But, if someone is thinking Olympus can produce a 300mm f2.8 lens any
smaller than Canon, they would be dead wrong.
But they *can* create a 150mm f2.8 that is smaller and is the
EQUIVALENT lens in terms of field of view. Sigh.

The lens STILL needs a
107mm of clear front aperture to meet it's speed claim.

Now it's 'front aperture'? See comment above. Happy to be corrected...

"bmoag" wrote in message
m...
There is ongoing research into ways to focus light for photographic use
that does not totally rely on glass/plastic as we know it particularly for
use with very small sensors.
The technology of imaging is evolving in ways that will not rely on
traditional materials just as digital sensors have replaced film for most
uses.
Bigger is not better even at this point in the development of digital
photography and will come to be seen as the liability it has always been
when better technical solutions become available.

While it is in principle possible to make a flat camera that from a
magnification viewpont has a very long lens or one that from a depth of
field and sharpness viewpoint has a very wide aperture using techniques
developed for long-baseline interferometry, the difficulty with these
techniques is that you don't get the sensitivity normally associated with
those large apertures. I can't see this approach as being other than a
niche solution.

Roger N. Clark (change username to rnclark) wrote:
bmoag wrote:

There is ongoing research into ways to focus light for photographic
use that does not totally rely on glass/plastic as we know it
particularly for use with very small sensors.
The technology of imaging is evolving in ways that will not rely on
traditional materials just as digital sensors have replaced film for
most uses.
Bigger is not better even at this point in the development of digital
photography and will come to be seen as the liability it has always
been when better technical solutions become available.

The flaw in this logic is number of photons. A smaller
camera with a smaller aperture lens collects fewer photons.
The signal-to-noise ratio in digital camera images is directly
related to the square root of the number of photons collected
in each pixel. Smaller pixels with smaller photons collected
also results in smaller dynamic range.

http://www.clarkvision.com/imagedeta...el.size.matter

Roger

Roger,
I don't think anybody implied a smaller aperture here. Yes, you'll
always need a large area to collect photons from (the "front element"),
but the rest of the "lens" (length etc) is not fixed by physical
considerations.

Take a look at this:
http://prola.aps.org/abstract/PRL/v85/i18/p3966_1

Cheers!

Mark² wrote:

You can't simply "get smaller" without reaching a point that bumps up
against limitations rooted in the properties of light itself. Others here
have discussed this at length (Think Roger and David Littleboy).


Mark,
When it comes to lenses, the only physical limitation is the
relationship of the area from which light is collected ("front element")
to the magnification of the image on the sensor. The rest is only
determined by what we use to make the lenses (currently, glass).

acl wrote:
Roger N. Clark (change username to rnclark) wrote:
bmoag wrote:
There is ongoing research into ways to focus light for photographic
use that does not totally rely on glass/plastic as we know it
particularly for use with very small sensors.
The technology of imaging is evolving in ways that will not rely on
traditional materials just as digital sensors have replaced film for
most uses.
Bigger is not better even at this point in the development of digital
photography and will come to be seen as the liability it has always
been when better technical solutions become available.

The flaw in this logic is number of photons. A smaller
camera with a smaller aperture lens collects fewer photons...

Roger,
I don't think anybody implied a smaller aperture here. Yes, you'll
always need a large area to collect photons from (the "front element"),
but the rest of the "lens" (length etc) is not fixed by physical
considerations.

Take a look at this:
http://prola.aps.org/abstract/PRL/v85/i18/p3966_1

hmmm scratching head
http://physicsweb.org/articles/news/9/4/12

"Paul Furman" wrote in message
et...
acl wrote:
Roger N. Clark (change username to rnclark) wrote:
bmoag wrote:
There is ongoing research into ways to focus light for photographic use
that does not totally rely on glass/plastic as we know it particularly
for use with very small sensors.
The technology of imaging is evolving in ways that will not rely on
traditional materials just as digital sensors have replaced film for
most uses.
Bigger is not better even at this point in the development of digital
photography and will come to be seen as the liability it has always
been when better technical solutions become available.

The flaw in this logic is number of photons. A smaller
camera with a smaller aperture lens collects fewer photons...

Roger,
I don't think anybody implied a smaller aperture here. Yes, you'll always
need a large area to collect photons from (the "front element"), but the
rest of the "lens" (length etc) is not fixed by physical considerations.

Take a look at this:
http://prola.aps.org/abstract/PRL/v85/i18/p3966_1

hmmm scratching head
http://physicsweb.org/articles/news/9/4/12

If it could be scaled to the dimensions required for photographic lenses
(the uses described seem to be on a very short distance scale) then it might
yield a lens sharper than current technology, but photographic lenses are
seldom diffraction-limited at large apertures anyway, so it would seem to be
a nonstarter.