Film vs. digital zoom on P&S

I would like to know if 3x zoom is the same on digital and film P&S
cameras.
What I mean is if I take a photo of something 100 feet away with a
digital camera that has 3x optical, and from the same spot I use
a 3x zoom on a film camera, is the zoom the same even if on
the digital camera the max is 58mm but on the film it's 130mm?

I am more concerned with a powerful zoom than a digital vs. film debate
or # of MPs, so what is a better value:
film:
CANON Sure Shot 150u Premier Camera Kit 38-150mm (4x) Zoom Lens - $120
CANON Sure Shot Z180u 4.7x Zoom (38-180mm) Lens - $140
KONICA MINOLTA Freedom Zoom 160c Camera with Date Function 37.5 - 160mm
Optical Zoom - $120

digital:
Canon powershot A75 3x 5.4-16.2mm - $200
""""""""""""""" s1 10x 5.8-58mm - $400
HP M305 3x 6-18mm - $150

Mr.Bolshoy Huy wrote:
I would like to know if 3x zoom is the same on digital and film P&S
cameras.
What I mean is if I take a photo of something 100 feet away with a
digital camera that has 3x optical, and from the same spot I use
a 3x zoom on a film camera, is the zoom the same even if on
the digital camera the max is 58mm but on the film it's 130mm?

Yes, but it may not be what you think. That 3X means 3 times closer.
The question is three times closer than what. In the case of a zoom lens it
means the subject will appear three times closer at one end of the zoom than
the other, or if you like three times further away than the other. It does
not tell you anything about how close it really will look.

Most people think it is like a pair of binoculars that may be identified
as 7X or 10X. In that case the 7X will make the subject appear to be 7
times closer. That 3X does not tell you a thing about how it will appear to
the camera.

35 mm film cameras have a 1X (that is the picture will look much like it
did to you ) at about 47 mm. So a 50X150 zoom will be able to take a photo
from about normal to three times closer. Most lenses however are likely to
be something like 35mm to 105mm so they can make something appear further
away than normal (very helpful for indoor groups) or about 2 times closer.

With digital, it gets more complex. There is no one size film for
digitals so what it normal for one digital may be telephoto or wide angle
for another. The accepted method of getting around this is the "multiplier"
effect. So if you have that 35-105 mm lens on a digital with a 1.6
multiplier you will have about the same effect as that 50X150mm zoom on a
film camera.

So to answer your questions about all those cameras you are going to
need to know their multiplier numbers.


--
Joseph Meehan

26 + 6 = 1 It's Irish Math

Mr.Bolshoy Huy wrote:
I would like to know if 3x zoom is the same on digital and film P&S
cameras.
What I mean is if I take a photo of something 100 feet away with a
digital camera that has 3x optical, and from the same spot I use
a 3x zoom on a film camera, is the zoom the same even if on
the digital camera the max is 58mm but on the film it's 130mm?

Yes, but it may not be what you think. That 3X means 3 times closer.
The question is three times closer than what. In the case of a zoom lens it
means the subject will appear three times closer at one end of the zoom than
the other, or if you like three times further away than the other. It does
not tell you anything about how close it really will look.

Most people think it is like a pair of binoculars that may be identified
as 7X or 10X. In that case the 7X will make the subject appear to be 7
times closer. That 3X does not tell you a thing about how it will appear to
the camera.

35 mm film cameras have a 1X (that is the picture will look much like it
did to you ) at about 47 mm. So a 50X150 zoom will be able to take a photo
from about normal to three times closer. Most lenses however are likely to
be something like 35mm to 105mm so they can make something appear further
away than normal (very helpful for indoor groups) or about 2 times closer.

With digital, it gets more complex. There is no one size film for
digitals so what it normal for one digital may be telephoto or wide angle
for another. The accepted method of getting around this is the "multiplier"
effect. So if you have that 35-105 mm lens on a digital with a 1.6
multiplier you will have about the same effect as that 50X150mm zoom on a
film camera.

So to answer your questions about all those cameras you are going to
need to know their multiplier numbers.


--
Joseph Meehan

26 + 6 = 1 It's Irish Math

"Mr.Bolshoy Huy" writes:

I would like to know if 3x zoom is the same on digital and film P&S
cameras.

It means the same thing.

What I mean is if I take a photo of something 100 feet away with a
digital camera that has 3x optical, and from the same spot I use
a 3x zoom on a film camera, is the zoom the same even if on
the digital camera the max is 58mm but on the film it's 130mm?

The "3x" relates to the ratio of the wide end of the zoom to the long
end of the zoom -- things are 3 times bigger when using the long end
than when using the wide end.

Two "3x" zooms can be very different; it's NOT an absolute statement
about the lens, it's only a relative statement.

A 30-90mm zoom is a 3x, and a 100-300mm zoom is also a 3x.

In practice, nearly all the film and digital P&S cameras with a 3x
zoom that I've seen have the wide end pretty close to the angle of
view you'd get with a 35mm lens on a full-frame 35mm camera.
--
David Dyer-Bennet, , http://www.dd-b.net/dd-b/
RKBA: http://noguns-nomoney.com/ http://www.dd-b.net/carry/
Pics: http://dd-b.lighthunters.net/ http://www.dd-b.net/dd-b/SnapshotAlbum/
Dragaera/Steven Brust: http://dragaera.info/

"Mr.Bolshoy Huy" writes:

I would like to know if 3x zoom is the same on digital and film P&S
cameras.

It means the same thing.

What I mean is if I take a photo of something 100 feet away with a
digital camera that has 3x optical, and from the same spot I use
a 3x zoom on a film camera, is the zoom the same even if on
the digital camera the max is 58mm but on the film it's 130mm?

The "3x" relates to the ratio of the wide end of the zoom to the long
end of the zoom -- things are 3 times bigger when using the long end
than when using the wide end.

Two "3x" zooms can be very different; it's NOT an absolute statement
about the lens, it's only a relative statement.

A 30-90mm zoom is a 3x, and a 100-300mm zoom is also a 3x.

In practice, nearly all the film and digital P&S cameras with a 3x
zoom that I've seen have the wide end pretty close to the angle of
view you'd get with a 35mm lens on a full-frame 35mm camera.
--
David Dyer-Bennet, , http://www.dd-b.net/dd-b/
RKBA: http://noguns-nomoney.com/ http://www.dd-b.net/carry/
Pics: http://dd-b.lighthunters.net/ http://www.dd-b.net/dd-b/SnapshotAlbum/
Dragaera/Steven Brust: http://dragaera.info/

"Mr.Bolshoy Huy" writes:

I would like to know if 3x zoom is the same on digital and film P&S
cameras.

It means the same thing.

What I mean is if I take a photo of something 100 feet away with a
digital camera that has 3x optical, and from the same spot I use
a 3x zoom on a film camera, is the zoom the same even if on
the digital camera the max is 58mm but on the film it's 130mm?

The "3x" relates to the ratio of the wide end of the zoom to the long
end of the zoom -- things are 3 times bigger when using the long end
than when using the wide end.

Two "3x" zooms can be very different; it's NOT an absolute statement
about the lens, it's only a relative statement.

A 30-90mm zoom is a 3x, and a 100-300mm zoom is also a 3x.

In practice, nearly all the film and digital P&S cameras with a 3x
zoom that I've seen have the wide end pretty close to the angle of
view you'd get with a 35mm lens on a full-frame 35mm camera.
--
David Dyer-Bennet, , http://www.dd-b.net/dd-b/
RKBA: http://noguns-nomoney.com/ http://www.dd-b.net/carry/
Pics: http://dd-b.lighthunters.net/ http://www.dd-b.net/dd-b/SnapshotAlbum/
Dragaera/Steven Brust: http://dragaera.info/

On Thu, 17 Feb 2005 10:43:16 -0600, Jim Townsend
wrote:

Mr.Bolshoy Huy wrote:

I would like to know if 3x zoom is the same on digital and film P&S
cameras.
What I mean is if I take a photo of something 100 feet away with a
digital camera that has 3x optical, and from the same spot I use
a 3x zoom on a film camera, is the zoom the same even if on
the digital camera the max is 58mm but on the film it's 130mm?

Unlike telescopes and binoculars, the 'X' in zoom doesn't describe
the magnification of the lens. In other words, a 3X zoom lens won't
necessarily make things look 3X closer

The zoom of a camera lens is calculated by dividing the maximum
focal length by the minimum focal length. Zoom describes the
range between the two focal lengths. It shows how wide and
narrow the field of view can be adjusted.

If a lens has a max of 115mm and a min of 38mm, then the zoom is:
115mm divided by 38mm = 3X

If a lens has a max of 30mm and a min of 10mm then the zoom is
30mm divided by 10mm = 3X

If a lens has a max of 300mm and a min of 100 mm then the zoom is:
300mm divided by 100mm = 3X

These lenses have drastically different magnifying power, but the
*zoom* is identical. Using the zoom factor alone to determine
how well a lens can magnify is pretty well useless.

Zoom is a verb used actually to describe the apparent motion you
see when you look through the viewfinder and vary the focal length.

If you increase the focal length while looking though the lens,
the subject appears to 'zoom' towards you. If you decrease
the focal length, the subject 'zooms' away. The movie industry
uses this often.. They call it zooming in and zooming out. Before
they had zoom lenses, they had to run the camera towards and away
from the subject using a wheeled trolly.

Fixed lenses have NO zoom. The Canon EF 1200mm lens is a powerful
lens when it comes to magnification, but since it has only one
focal length, you can't cause the apparent motion that changing
the focal length will cause.

The maximum focal length is 1200mm and so is the minimum.

1200 divided by 1200 = 1X

All fixed lenses have a zoom of 1X

Calculating magnification requires a bit more work.

It's generally accepted that a 50mm lens on a 35mm camera
approximates the field of view of the human eye. In other
words the lens has 1X magnification.

If you want 2X magnification then you need a 200mm lens
on your 35mm camera.

The 1200mm lens I referred to earlier has a magnification
of 1200 / 50 = 24X. But remember the zoom is only 1X.
Zoom and magnification are two different things.

To compare a 35mm zoom with a digital zoom, you have to
convert the film size to the sensor size. Most digicams
tell you the 35mm equivalent, so that is a good basis
of comparision.

For magnification you need to find the longest focal
length (35mm film equivalent) and divide by 50.


Best description I've read yet. Kudos!

On Thu, 17 Feb 2005 10:43:16 -0600, Jim Townsend
wrote:

Mr.Bolshoy Huy wrote:

I would like to know if 3x zoom is the same on digital and film P&S
cameras.
What I mean is if I take a photo of something 100 feet away with a
digital camera that has 3x optical, and from the same spot I use
a 3x zoom on a film camera, is the zoom the same even if on
the digital camera the max is 58mm but on the film it's 130mm?

Unlike telescopes and binoculars, the 'X' in zoom doesn't describe
the magnification of the lens. In other words, a 3X zoom lens won't
necessarily make things look 3X closer

The zoom of a camera lens is calculated by dividing the maximum
focal length by the minimum focal length. Zoom describes the
range between the two focal lengths. It shows how wide and
narrow the field of view can be adjusted.

If a lens has a max of 115mm and a min of 38mm, then the zoom is:
115mm divided by 38mm = 3X

If a lens has a max of 30mm and a min of 10mm then the zoom is
30mm divided by 10mm = 3X

If a lens has a max of 300mm and a min of 100 mm then the zoom is:
300mm divided by 100mm = 3X

These lenses have drastically different magnifying power, but the
*zoom* is identical. Using the zoom factor alone to determine
how well a lens can magnify is pretty well useless.

Zoom is a verb used actually to describe the apparent motion you
see when you look through the viewfinder and vary the focal length.

If you increase the focal length while looking though the lens,
the subject appears to 'zoom' towards you. If you decrease
the focal length, the subject 'zooms' away. The movie industry
uses this often.. They call it zooming in and zooming out. Before
they had zoom lenses, they had to run the camera towards and away
from the subject using a wheeled trolly.

Fixed lenses have NO zoom. The Canon EF 1200mm lens is a powerful
lens when it comes to magnification, but since it has only one
focal length, you can't cause the apparent motion that changing
the focal length will cause.

The maximum focal length is 1200mm and so is the minimum.

1200 divided by 1200 = 1X

All fixed lenses have a zoom of 1X

Calculating magnification requires a bit more work.

It's generally accepted that a 50mm lens on a 35mm camera
approximates the field of view of the human eye. In other
words the lens has 1X magnification.

If you want 2X magnification then you need a 200mm lens
on your 35mm camera.

The 1200mm lens I referred to earlier has a magnification
of 1200 / 50 = 24X. But remember the zoom is only 1X.
Zoom and magnification are two different things.

To compare a 35mm zoom with a digital zoom, you have to
convert the film size to the sensor size. Most digicams
tell you the 35mm equivalent, so that is a good basis
of comparision.

For magnification you need to find the longest focal
length (35mm film equivalent) and divide by 50.


Best description I've read yet. Kudos!

Jim,

I've noticed the following header on all of your recent postings:

"Note: The author of this message requested that it not be
archived. This message will be removed from Groups in 6
days (Feb 24, 8:43 am)."

Are you doing that on purpose? Why?

The posting that you made above contains useful information
that other people might like to find in searching Usenet (though
you may have meant to say "100mm" instead of "200mm"
above.)

Why do you cause of all your postings to disappear? It's
not as if they contain anything negative about you or
anyone else. Wouldn't you like the effort you put into them
to continue to be useful?

Just curious.

Alan

Jim,

I've noticed the following header on all of your recent postings:

"Note: The author of this message requested that it not be
archived. This message will be removed from Groups in 6
days (Feb 24, 8:43 am)."

Are you doing that on purpose? Why?

The posting that you made above contains useful information
that other people might like to find in searching Usenet (though
you may have meant to say "100mm" instead of "200mm"
above.)

Why do you cause of all your postings to disappear? It's
not as if they contain anything negative about you or
anyone else. Wouldn't you like the effort you put into them
to continue to be useful?

Just curious.

Alan