zoom feedback

N wrote:
> Roger, have you flipped?

No.
 >> Stay informed about: zoom feedback 

This message is not archived
 >> Stay informed about: zoom feedback 

"Roger N. Clark (change username to rnclark)" <username.TakeThisOut@qwest.net> wrote in
message news:46A18DC7.4060402@qwest.net...
>N wrote:
>> Roger, have you flipped?
>
> No.

All my Nikon zoom lenses show the focal length.

You suggest that the focal length is irrelevant. What about the effect on
perspective?
 >> Stay informed about: zoom feedback 

N wrote:
> "Roger N. Clark (change username to rnclark)" <username.DeleteThis@qwest.net> wrote in
> message news:46A18DC7.4060402@qwest.net...
>> N wrote:
>>> Roger, have you flipped?
>> No.
>
> All my Nikon zoom lenses show the focal length.

In the viewfinder? The OP wanted a "metric as he was zooming."
If you are looking at the metric and not at the scene, you are
looking at the wrong thing. Composition is more important than
what your focal length is.

> You suggest that the focal length is irrelevant. What about the effect on
> perspective?

Focal length does not change perspective. This is a common
error. See:

http://en.wikipedia.org/wiki/Perspective_distortion_(photography)

which nicely states:

"Perspective distortion is influenced by only two factors:
the distance of the subject matter from the camera and the
distance at which the photograph of the subject is viewed."

The distance to the subject and the composition you want
dictates focal length. In my opinion, one should examine
the scene, determine the composition, including moving
toward or away from the subject (thus changing perspective)
and then pick the focal length to fit the desired
composition. Choosing focal length first in my opinion
constrains the photographer, prevents "seeing" and
limits creativity. Obsessing about focal length moves
one further from creative composition.

Roger
 >> Stay informed about: zoom feedback 

N wrote:
[]
> Wide angle shots of people produce faces with large noses - do you
> agree?

No, I don't.

"Close" shots produce the distortion you mention.

If you use a wide-angle lens, and therefore need to be closer, you get the
problem.

David
 >> Stay informed about: zoom feedback 

On Sat, 21 Jul 2007 15:10:38 +1000
"N" <n.DeleteThis@st.y> wrote:

> "Roger N. Clark (change username to rnclark)" <username.DeleteThis@qwest.net>
> wrote in message news:46A18DC7.4060402@qwest.net...
> >N wrote:
> >> Roger, have you flipped?
> >
> > No.
>
> All my Nikon zoom lenses show the focal length.
>
> You suggest that the focal length is irrelevant. What about the
> effect on perspective?
>
>
You see that on the focusing screen and can change that with your feet.

--
Neil
Reverse ie and delete l for email.
 >> Stay informed about: zoom feedback 

On Jul 21, 10:28 am, "N" <n... DeleteThis @st.y> wrote:
> "Roger N. Clark (change username to rnclark)" <usern... DeleteThis @qwest.net> wrote in
> messagenews:46A19B82.1020404@qwest.net...
>
>
>
>
>
> > Focal length does not change perspective. This is a common
> > error. See:
>
> >http://en.wikipedia.org/wiki/Perspective_distortion_(photography)
>
> > which nicely states:
>
> > "Perspective distortion is influenced by only two factors:
> > the distance of the subject matter from the camera and the
> > distance at which the photograph of the subject is viewed."
>
> > The distance to the subject and the composition you want
> > dictates focal length. In my opinion, one should examine
> > the scene, determine the composition, including moving
> > toward or away from the subject (thus changing perspective)
> > and then pick the focal length to fit the desired
> > composition. Choosing focal length first in my opinion
> > constrains the photographer, prevents "seeing" and
> > limits creativity. Obsessing about focal length moves
> > one further from creative composition.
>
> > Roger
>
> The second part of that wiki is rubbish. The first part is a by-product of
> focal length.

Aha, so you think that whether an object obscures another object or
not depends on which lens I use, rather than where I am? Way to go!
 >> Stay informed about: zoom feedback 

Roger, have you flipped?

"Roger N. Clark (change username to rnclark)" <username DeleteThis @qwest.net> wrote in
message news:46A17FE5.1060906@qwest.net...
> Desert Dweller wrote:
>> On my Panasonic Lumix FZ8 when I zoom in there is a graphic on the
>> display that shows a progress bar and text reading "1X" or "2X" or "12X"
>> indicating my zoom level.
>>
>> I've been reading that focal length is very important in photography, as
>> a number expressed in mm.
>>
>> I would think the graphic indicator should display the mm metric as I am
>> zooming. Do "better" digital cameras do this? In other words, is the
>> "2X", "3X", "12X" text displayed just a "dummy indicator" on my consumer
>> quality camera? And a professional dSLR would display the actual mm value
>> focal length zoom level?
>
> No, DSLRs don't display the zoom factor nor focal length at all
> (at least in all the DSLRs that I use/used). There is simple
> reason: it is basically irrelevant to the image. By this, I mean
> forget about the focal length and concentrate on composition.
> If you need to zoom in (by focal length of by foot) so be it.
>
>> In other words, I read some professional photographers feel as though
>> 85mm to 100mm is the "sweet spot" for portraits. It sure would be nice if
>> the camera told you at what mm value you were zoomed.
>
> The professional photographer probably does not use a zoom
> lens for portraits (I've never seen one use a zoom for portraits).
>
> Try focusing on composition, and forget about what focal
> length you use.
>
> Roger
> Photos at: http://www.clarkvision.com
 >> Stay informed about: zoom feedback 

Desert Dweller <1 RemoveThis @invalidemail.org> wrote:

> On my Panasonic Lumix FZ8 when I zoom in there is a graphic on the display
> that shows a progress bar and text reading "1X" or "2X" or "12X"
> indicating my zoom level.
>
> I've been reading that focal length is very important in photography, as a
> number expressed in mm.
>
> I would think the graphic indicator should display the mm metric as I am
> zooming. Do "better" digital cameras do this? In other words, is the "2X",
> "3X", "12X" text displayed just a "dummy indicator" on my consumer quality
> camera? And a professional dSLR would display the actual mm value focal
> length zoom level?
>
>
> In other words, I read some professional photographers feel as though 85mm
> to 100mm is the "sweet spot" for portraits. It sure would be nice if the
> camera told you at what mm value you were zoomed.

As for the 85mm 'sweet spot,' that would be a focal length (for 35mm
film) at which it's easy to get a nice representational portrait of a
human torso. It doesn't mean it's the *only* focal length at which you
*should* take a portrait.

Your camera will record the focal length (true and 35mm equiv) in EXIF.
Take a number of test pictures at various zoom settings, and then check
the EXIF for those pictures. You could even make a chart to keep in your
kit bag. If you know you need a certain focal length, look it up on the
chart and set the zoom to that many 'times.'

I had an Oly C-5050Z. It had 'my' settings, which are presets. You could
set a focal length, focus distance, aperture, and aperture priority as a
preset. Instant zone focusing. So sad, that camera got dropped and died.

--
http://www.xoverboard.com/cartoons/2007/070416_argument.html
 >> Stay informed about: zoom feedback 

"Roger N. Clark (change username to rnclark)" <username.RemoveThis@qwest.net> wrote in
message news:46A19B82.1020404@qwest.net...
>
> Focal length does not change perspective. This is a common
> error. See:
>
> http://en.wikipedia.org/wiki/Perspective_distortion_(photography)
>
> which nicely states:
>
> "Perspective distortion is influenced by only two factors:
> the distance of the subject matter from the camera and the
> distance at which the photograph of the subject is viewed."
>
> The distance to the subject and the composition you want
> dictates focal length. In my opinion, one should examine
> the scene, determine the composition, including moving
> toward or away from the subject (thus changing perspective)
> and then pick the focal length to fit the desired
> composition. Choosing focal length first in my opinion
> constrains the photographer, prevents "seeing" and
> limits creativity. Obsessing about focal length moves
> one further from creative composition.
>
> Roger

The second part of that wiki is rubbish. The first part is a by-product of
focal length.

Wide angle shots of people produce faces with large noses - do you agree?
Here's a dog shot
http://www.flickr.com/photos/footrotdog/798228585/

Now watch some sport on TV. Do the objects in the distance look closer
together than they really are, as in distance from the viewer? Would it
matter how far you sit from the TV?

Here's a discussion on the subject:
http://www.flickr.com/groups/d80/discuss/72157600270986648/?search=perspective
 >> Stay informed about: zoom feedback 

N <n RemoveThis @st.y> wrote:
> "Roger N. Clark (change username to rnclark)" <username RemoveThis @qwest.net> wrote in
> message news:46A19B82.1020404@qwest.net...
>>
>> Focal length does not change perspective. This is a common
>> error. See:
>>
>> http://en.wikipedia.org/wiki/Perspective_distortion_(photography)
>>
>> which nicely states:
>>
>> "Perspective distortion is influenced by only two factors:
>> the distance of the subject matter from the camera and the
>> distance at which the photograph of the subject is viewed."
>>
>> The distance to the subject and the composition you want
>> dictates focal length. In my opinion, one should examine
>> the scene, determine the composition, including moving
>> toward or away from the subject (thus changing perspective)
>> and then pick the focal length to fit the desired
>> composition. Choosing focal length first in my opinion
>> constrains the photographer, prevents "seeing" and
>> limits creativity. Obsessing about focal length moves
>> one further from creative composition.
>>
>> Roger

> The second part of that wiki is rubbish. The first part is a by-product of
> focal length.

In combination with sensor size. Focal length on its own tells you
nothing if the size of the sensor isn't specified.

> Wide angle shots of people produce faces with large noses - do you agree?
> Here's a dog shot
> http://www.flickr.com/photos/footrotdog/798228585/

Because the nose is proportionally so much closer than the rest of the
face. It's the distance that does it, all the wide angle lens does is
allow to encompass the whole face and the different distances when the
nose is that close.

> Now watch some sport on TV. Do the objects in the distance look closer
> together than they really are, as in distance from the viewer? Would it
> matter how far you sit from the TV?

> Here's a discussion on the subject:
> http://www.flickr.com/groups/d80/discuss/72157600270986648/?search=perspective

That's not an informative discussion, it's a hugely long and tedious
argument in which most of the participants have failed the grasp the
fundamentals of perspective projection. All of the effects you mention
can be produced by a pin hole camera with no lens at all. So where has
the focal length gone?

--
Chris Malcolm cam RemoveThis @infirmatics.ed.ac.uk DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]
 >> Stay informed about: zoom feedback 

N wrote:
> "Roger N. Clark (change username to rnclark)" <username DeleteThis @qwest.net> wrote in
> message news:46A19B82.1020404@qwest.net...
>> Focal length does not change perspective. This is a common
>> error. See:
>>
>> http://en.wikipedia.org/wiki/Perspective_distortion_(photography)
>>
>> which nicely states:
>>
>> "Perspective distortion is influenced by only two factors:
>> the distance of the subject matter from the camera and the
>> distance at which the photograph of the subject is viewed."
>>
>> The distance to the subject and the composition you want
>> dictates focal length. In my opinion, one should examine
>> the scene, determine the composition, including moving
>> toward or away from the subject (thus changing perspective)
>> and then pick the focal length to fit the desired
>> composition. Choosing focal length first in my opinion
>> constrains the photographer, prevents "seeing" and
>> limits creativity. Obsessing about focal length moves
>> one further from creative composition.
>>
>> Roger
>
> The second part of that wiki is rubbish. The first part is a by-product of
> focal length.
>
> Wide angle shots of people produce faces with large noses - do you agree?
> Here's a dog shot
> http://www.flickr.com/photos/footrotdog/798228585/
>
> Now watch some sport on TV. Do the objects in the distance look closer
> together than they really are, as in distance from the viewer? Would it
> matter how far you sit from the TV?
>
> Here's a discussion on the subject:
> http://www.flickr.com/groups/d80/discuss/72157600270986648/?search=perspective

N,
By now with the multiple responses, you should realize that focal length
does not change perspective. The flickr discussion (as far as I read)
is wrong.

The wikipedia page is correct (not that wikipedia can't be wrong, but
here it is correct).

In the case of the wide angle lens and large noses, you can do the
same thing with a longer focal length lens and larger format
camera (to cover the same field of view). You can even do the same
thing with a digital mosaic: Take your wide angle picture close
up of the person, then zoom to maximum focal length and take multiple
frames to cover the same field of view and mosaic them.
You get the same effect in the images. The key is camera
distance to subject, not focal length.

You can do the same thing with your vision: move closer to a
person's face, and see how the nose appears larger compared
to more distant objects.

Roger
 >> Stay informed about: zoom feedback 

Chris Malcolm wrote:
> N <n RemoveThis @st.y> wrote:
>> "Roger N. Clark (change username to rnclark)" <username RemoveThis @qwest.net> wrote in
>> message news:46A19B82.1020404@qwest.net...
>>> Focal length does not change perspective. This is a common
>>> error. See:
>>>
>>> http://en.wikipedia.org/wiki/Perspective_distortion_(photography)
>>>
>>> which nicely states:
>>>
>>> "Perspective distortion is influenced by only two factors:
>>> the distance of the subject matter from the camera and the
>>> distance at which the photograph of the subject is viewed."
>>>
>>> The distance to the subject and the composition you want
>>> dictates focal length. In my opinion, one should examine
>>> the scene, determine the composition, including moving
>>> toward or away from the subject (thus changing perspective)
>>> and then pick the focal length to fit the desired
>>> composition. Choosing focal length first in my opinion
>>> constrains the photographer, prevents "seeing" and
>>> limits creativity. Obsessing about focal length moves
>>> one further from creative composition.
>>>
>>> Roger
>
>> The second part of that wiki is rubbish. The first part is a by-product of
>> focal length.
>
> In combination with sensor size. Focal length on its own tells you
> nothing if the size of the sensor isn't specified.
>
>> Wide angle shots of people produce faces with large noses - do you agree?
>> Here's a dog shot
>> http://www.flickr.com/photos/footrotdog/798228585/
>
> Because the nose is proportionally so much closer than the rest of the
> face. It's the distance that does it, all the wide angle lens does is
> allow to encompass the whole face and the different distances when the
> nose is that close.
>
>> Now watch some sport on TV. Do the objects in the distance look closer
>> together than they really are, as in distance from the viewer? Would it
>> matter how far you sit from the TV?
>
>> Here's a discussion on the subject:
>> http://www.flickr.com/groups/d80/discuss/72157600270986648/?search=perspective
>
> That's not an informative discussion, it's a hugely long and tedious
> argument in which most of the participants have failed the grasp the
> fundamentals of perspective projection. All of the effects you mention
> can be produced by a pin hole camera with no lens at all. So where has
> the focal length gone?
>
A simple way to see this: Take a picture of any object at the widest
angle of your zoom; then, _from the same position_ extend the zoom to
its longest FL and take another exposure. Crop both so that the same
image is shown in both exposures. No difference.
Allen
 >> Stay informed about: zoom feedback