Finally a decent travel zoom from Fuji

On Thu, 25 Jul 2019 20:15:24 -0400, nospam
wrote:

In article , Eric Stevens
wrote:

There is no such thing as an "equivalent" aperture. F4
is F4 both for a small sensor camera and a large sensor
camera.

for exposure, yes.
for depth of field, no.

Correct.

But its got nothing to do with the size of the sensor. It occurs only
as a result of the use of a shorter focal length lens.

nope. it has everything to do with the size of the sensor, and the lens
does not change.

Are you discussing the use of the same lens on two different cameras?

that doesn't matter.

I thought that other people were discussing the effect of using a
proportionally smaller (focal length and aperture dimensions) on two
proprtionally different cameras.

they might be, but again, that doesn't matter.

Then what exactly are you talking about?

In article , Alfred Molon wrote:

Sandman:
just as the
equivalent aperture is F6 (not F8, my bad)

There is no such thing as an "equivalent" aperture. F4
is F4 both for a small sensor camera and a large sensor
camera.

Then there is no such thing as "equivalent" focal length, 16-80 mm is the focal
length for the lens, regardless of what sensor you put under it.

Sigh...

--
Sandman

In article , Eric Stevens
wrote:


Then what exactly are you talking about?

equivalency. do try to keep up.

In article , Eric Stevens wrote:

Both physical factors of the lens are affected when
comparing crop to full format. That's why a f4 m43 lens has
the equivalent aperture of a f8 full format lens.

Alfred Molon:
Wrong again. An F4 lens is an F4 lens regardless of
sensor size

Sandman:
No one has said otherwise. A 16-80mm lens is a 16-80mm lens also
regardless of sensor size, but the *equivalent* focal length is
24-120mm, just as the equivalent aperture is F6 (not F8, my bad)

Alfred Molon:
, because the exposure is the same at F4 and
1/100s both on the small sensor camera and the large
sensor camera. But if you shoot at F8, the exposure time
will be 4x the exposure time at F4.

Sandman:
You're mixing exposure with equivalency. Exposure is light per
unit area, a smaller sensor has fewer of those units, so the
amount of total light is different, meaning that a crop sensor
camera need to boost its signal to create an equal enough image.
That's why crop sensors usually are said to have poorer ISO.

Let's consider two cameras, identical except that one is half the
size of the other. With the smaller camera, the focal length will be
halved, the lens diameter will be halved. i.e. the f value will
remain constant.

With the smaller camera, the sensor area will be one quarter. So too
will be the lens area. i.e. the amount of light entering the lens
will be reduced by a factor of four.

Exactly.

--
Sandman

On Fri, 26 Jul 2019 01:46:25 -0400, nospam
wrote:

In article , Eric Stevens
wrote:


Then what exactly are you talking about?

equivalency. do try to keep up.

Equivalency of what between what?

On 26 Jul 2019 06:02:44 GMT, Sandman wrote:

In article , Eric Stevens wrote:

Both physical factors of the lens are affected when
comparing crop to full format. That's why a f4 m43 lens has
the equivalent aperture of a f8 full format lens.

Alfred Molon:
Wrong again. An F4 lens is an F4 lens regardless of
sensor size

Sandman:
No one has said otherwise. A 16-80mm lens is a 16-80mm lens also
regardless of sensor size, but the *equivalent* focal length is
24-120mm, just as the equivalent aperture is F6 (not F8, my bad)

Alfred Molon:
, because the exposure is the same at F4 and
1/100s both on the small sensor camera and the large
sensor camera. But if you shoot at F8, the exposure time
will be 4x the exposure time at F4.

Sandman:
You're mixing exposure with equivalency. Exposure is light per
unit area, a smaller sensor has fewer of those units, so the
amount of total light is different, meaning that a crop sensor
camera need to boost its signal to create an equal enough image.
That's why crop sensors usually are said to have poorer ISO.

Let's consider two cameras, identical except that one is half the
size of the other. With the smaller camera, the focal length will be
halved, the lens diameter will be halved. i.e. the f value will
remain constant.

With the smaller camera, the sensor area will be one quarter. So too
will be the lens area. i.e. the amount of light entering the lens
will be reduced by a factor of four.

Exactly.

But you have snipped the next bit:

"But so too is the sensor area to be covered by the light so that
the intensity of the light falling on the sensor is the same in
both cameras.

In other words, when exposed at the same shutter speed and f value
the quantity of light per unit area falling on the respective
sensors will be the same. There is no need to calculate a different
aperture."

In article , Eric Stevens wrote:

Alfred Molon:
, because the exposure is the same at F4 and
1/100s both on the small sensor camera and the large sensor
camera. But if you shoot at F8, the exposure time will be 4x
the exposure time at F4.

Sandman:
You're mixing exposure with equivalency. Exposure is
light per unit area, a smaller sensor has fewer of those
units, so the amount of total light is different, meaning that
a crop sensor camera need to boost its signal to create an
equal enough image. That's why crop sensors usually are said
to have poorer ISO.

Eric Stevens:
Let's consider two cameras, identical except that one is half
the size of the other. With the smaller camera, the focal length
will be halved, the lens diameter will be halved. i.e. the f
value will remain constant.

With the smaller camera, the sensor area will be one quarter. So
too will be the lens area. i.e. the amount of light entering the
lens will be reduced by a factor of four.

Sandman:
Exactly.

But you have snipped the next bit

Because it shifted to exposure from equivalency. They're not the same thing.
To create two equivalent images from two different sensors, you can't use the
same exposure.

http://www.josephjamesphotography.com/equivalence/#equivalence



--
Sandman

In article , Eric Stevens
wrote:

Let's consider two cameras, identical except that one is half the
size of the other. With the smaller camera, the focal length will be
halved, the lens diameter will be halved. i.e. the f value will
remain constant.

With the smaller camera, the sensor area will be one quarter. So too
will be the lens area. i.e. the amount of light entering the lens
will be reduced by a factor of four.

Exactly.

But you have snipped the next bit:

"But so too is the sensor area to be covered by the light so that
the intensity of the light falling on the sensor is the same in
both cameras.

In other words, when exposed at the same shutter speed and f value
the quantity of light per unit area falling on the respective
sensors will be the same. There is no need to calculate a different
aperture."

but you have snipped the next bit:

there is to obtain equivalent results.

In article ,
Sandman wrote:

Eric Stevens:
Let's consider two cameras, identical except that one is half
the size of the other. With the smaller camera, the focal length
will be halved, the lens diameter will be halved. i.e. the f
value will remain constant.

With the smaller camera, the sensor area will be one quarter. So
too will be the lens area. i.e. the amount of light entering the
lens will be reduced by a factor of four.

Sandman:
Exactly.

But you have snipped the next bit

Because it shifted to exposure from equivalency. They're not the same thing.

true

To create two equivalent images from two different sensors, you can't use the
same exposure.

false

On 26 Jul 2019 11:47:17 GMT, Sandman wrote:

In article , Eric Stevens wrote:

Alfred Molon:
, because the exposure is the same at F4 and
1/100s both on the small sensor camera and the large sensor
camera. But if you shoot at F8, the exposure time will be 4x
the exposure time at F4.

Sandman:
You're mixing exposure with equivalency. Exposure is
light per unit area, a smaller sensor has fewer of those
units, so the amount of total light is different, meaning that
a crop sensor camera need to boost its signal to create an
equal enough image. That's why crop sensors usually are said
to have poorer ISO.

Eric Stevens:
Let's consider two cameras, identical except that one is half
the size of the other. With the smaller camera, the focal length
will be halved, the lens diameter will be halved. i.e. the f
value will remain constant.

With the smaller camera, the sensor area will be one quarter. So
too will be the lens area. i.e. the amount of light entering the
lens will be reduced by a factor of four.

Sandman:
Exactly.

But you have snipped the next bit

Because it shifted to exposure from equivalency. They're not the same thing.
To create two equivalent images from two different sensors, you can't use the
same exposure.

http://www.josephjamesphotography.com/equivalence/#equivalence

Aah! I get you. Most people focus on the exposure triangle. You have a
different triangle in mind.