Are IS lenses doomed ?

King Sardon wrote:
"Neil Harrington" wrote:

"dennis@home" wrote:

Not every lens characteristic changes when you change sensor size.
Things like the DOF stay the same.
They only change if you move the camera or zoom to reflect the change in
field of view.
No, DoF changes too, though not in the same degree.

Right, you get about 1 stop DoF advantage with the APS-C-type sensors
compared to 35 mm.

You get that by using a smaller aperture. A shorter lens will
have the same speed at a proportionally smaller aperture. The
the total light falling in frame will be the same, so it's not
the advantage it might appear.

If you want the larger depth-of-field but have the larger sensor,
you could either:

Use the shorter lens smaller aperture, and crop down to the
center of the image, just as happens with the smaller sensor.

Use the longer focal length, but up ISO and stop down. The
same amount of light falls on sensor.


--
--Bryan

Bill Funk wrote:
Bryan Olson

Prometheus wrote:
Why not quote the angle of view that the lens gives with the sensor?
Most users are not interested in the focal length per se. I realise that
macro work and photometry can require more than the angle of view.
Yes, that seems like a good idea. Call an angle an angle and a
focal length a focal length.

Stating everything relative to 35mm full-frame is silly, especially
if it's not even what most people use.

Yeah, that'll work.
Given a tree line at starts 217' away, with the trees an average of
13' apart, how many trees does it take to make up a 57° angle of view?

Is that easier to answer given focal length instead of the angle
of view?

The problem is that most serious photographers are familiar with lens
coverage in terms of focal length as it pertains to 35mm photography
now.

That's a point. In the U.S. we couldn't even go metric.


--
--Bryan

"Skip" wrote in message
...
"Pete D" wrote in message
...

"Alan Browne" wrote in message
...
VC wrote:
The release of Sony Alpha with the image stabilization in camera (
although this is not new) highlighted the fundamental problem with
Canon.
Canon have had IS lenses long ago as it would be very difficult to do
in-camera stabilization in film cameras. The digital cameras had to
support older lenses including the ones with IS. If Canon developed a
camera with in-body stabilization it would hurt Canon sales and
reputation.
So I guess Canon will continue with its nonstabilized bodies and when
Sony or someone else will achieve the same image sensor quality Canon
will find itself in a very difficult situation.
There is a very small advantage in having IS in the lens but it is not
significant enough to grant double and triple cost of the same quality
lenses.

For specific shooting, yes there is an advantage to "in lens"
stabilization... about a stop to 2 stops worth over the "in camera".

What testing proved this, the only testing I have seen is in a German mag
where they showed there was little difference between the two systems?

The advantages of the in-camera are a margin (2 stops, sometimes more)
and all your lenses benefit.

And no, in camera will never achieve what "in lens" stab can do.

What testing proved this, the only testing I have seen is in a German mag
where they showed there was little difference between the two systems?


Would that be the same German magazine that came up with a light fall of
on the corners of a 5D sensor in the order of 3-4 stops?
I keep hearing about this test, but I've never seen it. There were some
tests posted here, on this newsgroup, a couple of months ago, that
indicated 1-2 stops for in camera on a DSLR (different from p&s results)
and 2-4 stops for in lens IS.

So pretty much any testing is old, inconclusive and out of date and done by
someone that no one can point to? Show me the detailed repeatable testing!
If it is anything like the Phil Askey DP Review testing then it is pretty
disgustingly biased and done outside the guidelines from the manuals anyway.

"Prometheus" wrote in message
...
In article , Skip
writes
"dennis@home" wrote in message
. ..

"Neil Harrington" wrote in message
. ..

Exactly. And I think that even long after 35mm is dead and gone, its
use
as a familiar standard for focal lengths will probably go on and on.
It's
already *the* standard of comparison for focal length conversions, and
once such a standard is established there's no obvious reason to change
it.

You can't just convert the focal length and come up with the correct
answer.
Not every lens characteristic changes when you change sensor size.
Things like the DOF stay the same.
They only change if you move the camera or zoom to reflect the change in
field of view.

Actually, I believe DOF is different, but, otherwise, everything else,
like
perspective, stays the same.

The perspective depends on where you stand relative to the scene; neither
the size of the sensor nor the length of the lens, real or pretend, can
effect it.


Funny, I think that's what I said.

--
Skip Middleton
www.shadowcatcherimagery.com
www.pbase.com/skipm

"Bryan Olson" wrote in message
et...
Skip wrote:
"Bryan Olson" wrote:
Prometheus wrote:
Why not quote the angle of view that the lens gives with the sensor?
Most users are not interested in the focal length per se. I realise
that macro work and photometry can require more than the angle of view.

Yes, that seems like a good idea. Call an angle an angle and a
focal length a focal length.

Stating everything relative to 35mm full-frame is silly, especially
if it's not even what most people use.

Well, with so many sensor sizes, and proportions, on the market, 35mm
probably seems like the best to pick for a standard, since most of the
digital cameras, both point and shoot and DSLR, are similar in size, or
at least started out that way, to 35mm film cameras. And, originally,
most of the customers who migrated to digital came there from 35mm film.
What standard would you propose?

The proposal I like is to specify angle-of-view directly, without
reference to a standard sensor size.


--
--Bryan

The problem with that is that is would require re-educating nearly every
photographer and marketing maven, not to mention adding another layer of
incomprehensibility for every newbie. Who, among us, could have envisioned,
say, a 54 deg angle of view when we first started in photography?

--
Skip Middleton
www.shadowcatcherimagery.com
www.pbase.com/skipm

"Pete D" wrote in message
...

"Skip" wrote in message
...
"Pete D" wrote in message
...

"Alan Browne" wrote in message
...
VC wrote:
The release of Sony Alpha with the image stabilization in camera (
although this is not new) highlighted the fundamental problem with
Canon.
Canon have had IS lenses long ago as it would be very difficult to do
in-camera stabilization in film cameras. The digital cameras had to
support older lenses including the ones with IS. If Canon developed a
camera with in-body stabilization it would hurt Canon sales and
reputation.
So I guess Canon will continue with its nonstabilized bodies and when
Sony or someone else will achieve the same image sensor quality Canon
will find itself in a very difficult situation.
There is a very small advantage in having IS in the lens but it is not
significant enough to grant double and triple cost of the same quality
lenses.

For specific shooting, yes there is an advantage to "in lens"
stabilization... about a stop to 2 stops worth over the "in camera".

What testing proved this, the only testing I have seen is in a German
mag where they showed there was little difference between the two
systems?

The advantages of the in-camera are a margin (2 stops, sometimes more)
and all your lenses benefit.

And no, in camera will never achieve what "in lens" stab can do.

What testing proved this, the only testing I have seen is in a German
mag where they showed there was little difference between the two
systems?


Would that be the same German magazine that came up with a light fall of
on the corners of a 5D sensor in the order of 3-4 stops?
I keep hearing about this test, but I've never seen it. There were some
tests posted here, on this newsgroup, a couple of months ago, that
indicated 1-2 stops for in camera on a DSLR (different from p&s results)
and 2-4 stops for in lens IS.

So pretty much any testing is old, inconclusive and out of date and done
by someone that no one can point to? Show me the detailed repeatable
testing! If it is anything like the Phil Askey DP Review testing then it
is pretty disgustingly biased and done outside the guidelines from the
manuals anyway.

Where did I say that? I'm still waiting to see this mythical IS test from
this not so mythical German magazine, which seems only to be available in
print, not on line, and not in the US. If the test you mention is from the
same German magazine that posted those "vignetting" results for the 5D, it
is even more biased than anything Phil has produced, believe me.
I'm still waiting, also, for that detailed repeatable testing. Like I
said, there were some posted here, but that's it.

--
Skip Middleton
www.shadowcatcherimagery.com
www.pbase.com/skipm

"Skip" wrote in message
...
"dennis@home" wrote in message
...

"Neil Harrington" wrote in message
. ..

Exactly. And I think that even long after 35mm is dead and gone, its use
as a familiar standard for focal lengths will probably go on and on.
It's already *the* standard of comparison for focal length conversions,
and once such a standard is established there's no obvious reason to
change it.

You can't just convert the focal length and come up with the correct
answer.
Not every lens characteristic changes when you change sensor size.
Things like the DOF stay the same.
They only change if you move the camera or zoom to reflect the change in
field of view.

Actually, I believe DOF is different, but, otherwise, everything else,
like perspective, stays the same.

No.
All you have effectively done is put a mask over the film.
Unless you actually move it all stays the same, just less of the scene.

"Neil Harrington" wrote in message
...

DoF is different, of course. But I think that's secondary for most users
most of the time, in choosing a focal length. The *difference* in DoF for
dSLRs I think is relatively small, especially since the greater
magnification for the final print cancels some of the difference out.


Different?
If you put a 50mm lens on a camera the DOF will be the same whatever
film/sensor is fitted.

"Neil Harrington" wrote in message
. ..

Not every lens characteristic changes when you change sensor size.
Things like the DOF stay the same.
They only change if you move the camera or zoom to reflect the change in
field of view.

No, DoF changes too, though not in the same degree.

No, it can't.
The formulae for DOF doesn't know what size the sensor is.
It is purely the distance to the subject, the *real* focal length and the
aperture.
I.e. a 50mm lens gives the same DOF on any format.

dennis@home wrote:
"Neil Harrington" wrote in message
...

DoF is different, of course. But I think that's secondary for most users
most of the time, in choosing a focal length. The *difference* in DoF for
dSLRs I think is relatively small, especially since the greater
magnification for the final print cancels some of the difference out.


Different?
If you put a 50mm lens on a camera the DOF will be the same whatever
film/sensor is fitted.

No, the DOF will be smaller for a smaller sensor/film format, all else
equal. This is because DOF is defined on a print, and to obtain the
same sized print from two sensors of different sizes, the image from
the smaller one must be enlarged more, thus enlarging the circle of
confusion more. In other words, a smaller sensor needs a smaller circle
of confusion, so the DOF is smaller, if all else (focal length,
aperture etc) is equal.

I hope this time the thread does not degenerate into a stupid argument
(please think about this before saying it's wrong!).