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scale and ratio

 
 
Don
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      08-30-2004
Folks

Can someone explain the ratio of 3:2 which is what I am advised is the ratio
of many digital camera sensors. How does this work to the printing of shots
on photographic paper sizes such as 6 by 4 and 8 by 10 along the relevant
issues of cropping by comparison to a 35 mm negative.
--
Don From Down Under


 
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Colin D
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      08-30-2004
Don wrote:
>
> Folks
>
> Can someone explain the ratio of 3:2 which is what I am advised is the ratio
> of many digital camera sensors. How does this work to the printing of shots
> on photographic paper sizes such as 6 by 4 and 8 by 10 along the relevant
> issues of cropping by comparison to a 35 mm negative.
> --
> Don From Down Under


Not quite right there, most consumer digitals with non-interchangeable
lenses have an aspect ratio of 4:3. Interchangeable lens SLR's like
Canon and Nikon have aspect ratios of 3:2 to conform with the 35mm film
ratio of 3:2.

An aspect ratio of 4:3 means that the image is 4 units long by 3 units
high, e.g. a 4x3-inch or a 8x6-inch print can be had with no cropping.
An aspect ratio of 3:2 likewise means the image will fit without
cropping on 6x4 paper, but not 8x10 paper. To get an 8-inch wide image,
a 3:2 ratio image would be 12 inches long, so you would lose 2 inches of
image.

Note that cameras with a 4:3 ratio sensor produce images that will be
cropped to fit on 6x4 paper, since the image when set to 6 inches long
will be 4.5 inches wide.

Colin D.
 
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stanb
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      08-30-2004

"Don" <(E-Mail Removed)> wrote in message
newsYCYc.13213$(E-Mail Removed)...
> Folks
>
> Can someone explain the ratio of 3:2 which is what I am advised is the

ratio
> of many digital camera sensors. How does this work to the printing of

shots
> on photographic paper sizes such as 6 by 4 and 8 by 10 along the relevant
> issues of cropping by comparison to a 35 mm negative.
> --
> Don From Down Under
>
>


it simply means that the width of the sensor is 1 and a half times the
height of it. It is the same ratio as 6*4 prints which is roughly the same
as a 35 mm negative.

5*7 is about 1:1.4 and 8*10 is a 4:5 ratio - in both cases you will loose a
little from the long edge if you enlarge the short edge to fit perfectly.

to complicate things, most digicam sensors (not DSLRs) have a 4:3 ratio
which is the same as your TV - when printed on 6*4 you either loose a bit
top and bottom, or have margins either side.


 
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Don
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      08-30-2004
Colin

thanks, I found some good information at the following site on ratios


http://bj.canon.co.jp/english/photopaper/

This site has some other pretty informative stuff as well.

regards

Don from Down Under


"Colin D" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Don wrote:
> >
> > Folks
> >
> > Can someone explain the ratio of 3:2 which is what I am advised is the

ratio
> > of many digital camera sensors. How does this work to the printing of

shots
> > on photographic paper sizes such as 6 by 4 and 8 by 10 along the

relevant
> > issues of cropping by comparison to a 35 mm negative.
> > --
> > Don From Down Under

>
> Not quite right there, most consumer digitals with non-interchangeable
> lenses have an aspect ratio of 4:3. Interchangeable lens SLR's like
> Canon and Nikon have aspect ratios of 3:2 to conform with the 35mm film
> ratio of 3:2.
>
> An aspect ratio of 4:3 means that the image is 4 units long by 3 units
> high, e.g. a 4x3-inch or a 8x6-inch print can be had with no cropping.
> An aspect ratio of 3:2 likewise means the image will fit without
> cropping on 6x4 paper, but not 8x10 paper. To get an 8-inch wide image,
> a 3:2 ratio image would be 12 inches long, so you would lose 2 inches of
> image.
>
> Note that cameras with a 4:3 ratio sensor produce images that will be
> cropped to fit on 6x4 paper, since the image when set to 6 inches long
> will be 4.5 inches wide.
>
> Colin D.



 
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David Littlewood
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      08-30-2004
In article <xYCYc.13213$(E-Mail Removed)>, Don
<(E-Mail Removed)> writes
>Folks
>
>Can someone explain the ratio of 3:2 which is what I am advised is the ratio
>of many digital camera sensors. How does this work to the printing of shots
>on photographic paper sizes such as 6 by 4 and 8 by 10 along the relevant
>issues of cropping by comparison to a 35 mm negative.
>--
>Don From Down Under
>
>

It's not complicated; it simply means the long side is 1.5 (i.e. 3/2)
times the length of the short side. It is more usefully termed "aspect
ratio", to make it clear what is being described. The use of "3:2"
rather than "1.5:1" is just a preference many people have for sticking
to whole numbers.

Aspect ratio = (length of long side)/(length of short side).

35mm negatives are 36mm x 24mm, so have exactly the same 3:2 aspect
ratio, as would paper in 6x4 or 12x8 sizes, or negatives in 6x9cm size.
All of these will therefor work well together without cropping the
picture or wasting paper. However, some people find it too elongated to
suit many images.

10x8 paper of course has an aspect ratio of 1.25:1, or 5:4. It is thus
impossible to get all the content of a 35mm negative on to paper of this
size without leaving large blank margins down the longer sides.

Personally I find 1.4:1 is the most generally acceptable aspect ratio -
but that's because I'm European and virtually everything I read or write
is on A4 size paper (1.414:1 aspect ratio).

David
--
David Littlewood
 
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Hap Shaughnessy
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      08-31-2004
On Mon, 30 Aug 2004 12:56:40 +0100, David Littlewood
<(E-Mail Removed)> wrote:

>In article <xYCYc.13213$(E-Mail Removed)>, Don
><(E-Mail Removed)> writes
>>Folks
>>
>>Can someone explain the ratio of 3:2 which is what I am advised is the ratio
>>of many digital camera sensors. How does this work to the printing of shots
>>on photographic paper sizes such as 6 by 4 and 8 by 10 along the relevant
>>issues of cropping by comparison to a 35 mm negative.
>>--
>>Don From Down Under


Everyone else has already answered your question but here's some extra
info that may be useful.

This afternoon Google.com helped me find ...

Print Sizes Aspect Ratio
4 6 3:2
5 7 7:5
8 10 5:4
11 14 14:11

.... along with ...

Continuum Javascript Aspect Ratio Calculator
http://www.continuum2.com/js_ratio.php

Hap
 
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David Littlewood
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      08-31-2004
In article <(E-Mail Removed)>, Hap Shaughnessy
<(E-Mail Removed)> writes
>On Mon, 30 Aug 2004 12:56:40 +0100, David Littlewood
><(E-Mail Removed)> wrote:
>
>>In article <xYCYc.13213$(E-Mail Removed)>, Don
>><(E-Mail Removed)> writes
>>>Folks
>>>
>>>Can someone explain the ratio of 3:2 which is what I am advised is the ratio
>>>of many digital camera sensors. How does this work to the printing of shots
>>>on photographic paper sizes such as 6 by 4 and 8 by 10 along the relevant
>>>issues of cropping by comparison to a 35 mm negative.
>>>--
>>>Don From Down Under

>
>Everyone else has already answered your question but here's some extra
>info that may be useful.
>
>This afternoon Google.com helped me find ...
>
>Print Sizes Aspect Ratio
>4 6 3:2
>5 7 7:5
>8 10 5:4
>11 14 14:11
>
>... along with ...
>
>Continuum Javascript Aspect Ratio Calculator
>http://www.continuum2.com/js_ratio.php
>

Forgive me if I am missing something here, but why would anyone need
Google to tell them that 10x 8 paper has an aspect ratio of 5:4? I
struggle to imagine anyone even needing a calculator for this feat.
--
David Littlewood
 
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Hap Shaughnessy
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Posts: n/a
 
      08-31-2004
On Tue, 31 Aug 2004 09:50:39 +0100, David Littlewood
<(E-Mail Removed)> wrote:

>In article <(E-Mail Removed)>, Hap Shaughnessy
><(E-Mail Removed)> writes
>>On Mon, 30 Aug 2004 12:56:40 +0100, David Littlewood
>><(E-Mail Removed)> wrote:
>>
>>>In article <xYCYc.13213$(E-Mail Removed)>, Don
>>><(E-Mail Removed)> writes
>>>>Folks
>>>>
>>>>Can someone explain the ratio of 3:2 which is what I am advised is the ratio
>>>>of many digital camera sensors. How does this work to the printing of shots
>>>>on photographic paper sizes such as 6 by 4 and 8 by 10 along the relevant
>>>>issues of cropping by comparison to a 35 mm negative.
>>>>--
>>>>Don From Down Under

>>
>>Everyone else has already answered your question but here's some extra
>>info that may be useful.
>>
>>This afternoon Google.com helped me find ...
>>
>>Print Sizes Aspect Ratio
>>4 6 3:2
>>5 7 7:5
>>8 10 5:4
>>11 14 14:11
>>
>>... along with ...
>>
>>Continuum Javascript Aspect Ratio Calculator
>>http://www.continuum2.com/js_ratio.php
>>

>Forgive me if I am missing something here, but why would anyone need
>Google to tell them that 10x 8 paper has an aspect ratio of 5:4? I
>struggle to imagine anyone even needing a calculator for this feat.


Because for my camera's image dimensions I crop before sending to
print rather than trusting the photo developer do it. Knowing the
correct aspect ratios and using the handy calculator mentioned above I
got the image dimensions I need for cropping. My math sucks and it
made my day easier.

I shoot at my camera's full 4.0 MP resolution with an aspect ratio of
4:3 / 2304 x 1728 pixels that is perfect for monitor viewing or
wallpaper but no good for print.

I made the table below that works for me.

Print Sizes Ratio Digital Dimensions
4 6 3:2 1536 x 2304 pixels
5 7 7:5 1646 x 2304 pixels
8 10 5:4 1728 x 2160 pixels
11 14 14:11 1728 x 2199 pixels

See ya,

Hap
 
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