Aspect ratio 3:2 or 2:3

[Abitconfused]

I believe a 35mm format has an aspect ratio of 3:2 (length x height) but I also see this listed as 2:3. Which is most correct?

[Ken MT]

It's a bit like buying timber, US buys 2x4, other places buy 4x2-same stuff!
Could also be landscape or portrait.

[DanK]

They are identical, just listing a different side first. It's more common to list the long side first, but it's exactly the same information either way.

[dem]

I think it is more common to hear 3:2 rather than 2:3 when people talk about a camera sensor. But then they print 12x18 not 18x12...

Would you say a full frame sensor is 24x36 mm or 36x24 mm?

[davidedric]

Most people in the world who still print, print A4, A5 etc.

[Manfred M]

Most people in the world who still print, print A4, A5 etc.

Unless you are in North America where US paper sizes are in use, even in officially metric Canada.

[Mike Buckley]

It's a bit like buying timber, US buys 2x4, other places buy 4x2-same stuff!

And to add to the confusion, neither is actually 2x4 nor 4x2.

[Dave Humphries]

Which way are you holding the camera Ed?

I'd say the 'rule' is width x height, for the intended viewer of the image, so that changes it as follows;

3:2 for landscape (or horizontal) orientation images
2:3 for portrait (or vertical) orientation images

This of course means that for TV, movies and videos (things we should never* shoot vertical orientation), it is predominantly (read always) said: 3:2, or more likely 16:9, or in olden days 4:3, etc. (but you get the idea)

* of course, we should never say 'never'


I'd say the same 'rule' holds true for prints too, for example, I would say 10 x 8.
However, that will vary across different industries; some may always say it 'smallest x largest' (or vice versa), e.g. picture frame makers and certainly paper makers, where the orientation of an image or printed page has no relevance, so it makes sense for them to standardise one way or the other to avoid confusion when discussing 10 x 8 or 10 x 12.

Cheers, Dave

[george013]

And to add to the confusion, neither is actually 2x4 nor 4x2.

Scraped or raw?

George

[Tronhard]

Unless you are in North America where US paper sizes are in use, even in officially metric Canada.

That is one thing I find frustrating. The proportions of Metric A sizes are brilliant from the point of view of up scaling up and down. I find it MUCH better than having both letter and legal paper, fewer paper trays for a start.

[Tronhard]

Which way are you holding the camera Ed?

I'd say the 'rule' is width x height, for the intended viewer of the image, so that changes it as follows;

Cheers, Dave

Yet as I recall when we talked about a film size we always referred to 24x36 for a 35mm!

[george013]

CaptureNx2 and ViewNx are using landscape or portrait 4x6.

George

[DanK]

I think there is a convention, but nonetheless, it still doesn't matter

The original question was:

Which is most correct?

I think the simple answer is: "neither. They are the same information regardless."

It's instructive to look at LR. The cropping dimensions it offers are not affected by whether the image is in portrait or landscape. The first group of presets are all either square or small-number-first. These include common frame and print dimensions, such as 8 x 10 and 5 x 7. The second group are in the opposite direction: 4:3, 16:9, 16:10. The first two of these are common sensor and display dimensions.

I don't know why LR did this, but I am guessing that it is because the entirely arbitrary an inconsequential habit most people have is to present the ratio small number first when talking about prints and large number first when talking about some other media. For example, Dick Blick, a very large art supply company in the US, has this page listing one type of photo frame. All the dimensions are small number first. The aspect ratio selector on my lumix lx-100 has all ratios larger number first, e.g., 3:2 and 4:3, because the arbitrary custom is to label sensors this way.

The bottom line is it simply doesn't matter. Neither is "more correct," since they convey the identical information. If I wrote in a post that in using my Lumix I most often use 3:4 despite the fact that my DSLRs are 2:3 because I usually end up cropping on the long end of my DSLR captures, no one would be puzzled and would wonder, 'how come his DSLRs are 2:3 rather than 3:2'?

[xpatUSA]

I think there is a convention, but nonetheless, it still doesn't matter


I think the simple answer is: "neither. They are the same information regardless."

It's instructive to look at LR. The cropping dimensions it offers are not affected by whether the image is in portrait or landscape. The first group of presets are all either square or small-number-first. These include common frame and print dimensions, such as 8 x 10 and 5 x 7. The second group are in the opposite direction: 4:3, 16:9, 16:10. The first two of these are common sensor and display dimensions.

I don't know why LR did this, but I am guessing that it is because the entirely arbitrary an inconsequential habit most people have is to present the ratio small number first when talking about prints and large number first when talking about some other media. For example, Dick Blick, a very large art supply company in the US, has this page listing one type of photo frame. All the dimensions are small number first. The aspect ratio selector on my lumix lx-100 has all ratios larger number first, e.g., 3:2 and 4:3, because the arbitrary custom is to label sensors this way.

The bottom line is it simply doesn't matter. Neither is "more correct," since they convey the identical information. If I wrote in a post that in using my Lumix I most often use 3:4 despite the fact that my DSLRs are 2:3 because I usually end up cropping on the long end of my DSLR captures, no one would be puzzled and would wonder, 'how come his DSLRs are 2:3 rather than 3:2'?

The Wiki (today's de facto standard?) defines aspect ratio as width:height, not height:width - i.e. an APS-C sensor is 3:2, not 2:3.

https://en.wikipedia.org/wiki/Aspect...ll_photography

APS is an old film standard:

https://en.wikipedia.org/wiki/Advanced_Photo_System

Interestingly, there is a table in there which shows print sizes t'other way round (back-asswards) as is still common to this very day:

"The film is 24 mm wide, and has three image formats:

• H for "High Definition" (30.2 × 16.7 mm; aspect ratio 16:9; 4×7" print)
• C for "Classic" (25.1 × 16.7 mm; aspect ratio 3:2; 4×6" print)
• P for "Panoramic" (30.2 × 9.5 mm; aspect ratio 3:1; 4×11" print)"

Which makes a portrait shot have a 2:3 aspect ratio but taken by a 3:2 sensor or film and printed at 6x4".

Hmmm . . . I wonder if the standard for metric paper mentions "aspect ratio" as in, for example, A4 vs A3? Being a naturalized Texan, I have no idea.

[Donald]

which way are you holding the camera ed?

I'd say the 'rule' is width x height, for the intended viewer of the image, so that changes it as follows;

3:2 for landscape (or horizontal) orientation images
2:3 for portrait (or vertical) orientation images

That is the convention used by a great many professional photographers and publishers when writing about images.

[kazuyar]

one of my pet hates is the people that use phone cameras and never turn them on their side, especially with video
really winds me up

[rpcrowe]

one of my pet hates is the people that use phone cameras and never turn them on their side, especially with video
really winds me up

I agree... There should be a program for smart phones that tells the user... "Turn me on my side, DUMMIE!" when video shooting is detected!

Otherwise, smart phones like my iPhone 6S+ can do a pretty darn good job on video and the iMovie can also do a pretty good, in-phone, editing job for simple videos...

[Tronhard]

The Wiki (today's de facto standard?)
Hmmm . . . I wonder if the standard for metric paper mentions "aspect ratio" as in, for example, A4 vs A3? Being a naturalized Texan, I have no idea.

The beauty of metric A-series paper is that it conducted on the golden rectangle: Simply put (I hope!) The proportions of the paper are h1.414xw1. So that means if I have an A0 size it is twice the AREA of an A1, which is twice the area of an A2. What is so good about the proportions of the paper is that even if the area is halved (or doubled) the proportions of the paper remain identical. Which makes an image fitting on one size able to be blown up or reduced and still keep its scale on the paper. As one reduces the shortest dimension become the longest dimension of the next size down, as per this:

http://www.paper-sizes.com/iso-stand...es-paper-sizes

It is particularly valuable iin scaling technical drawings For example a drawing that was initially A1 at a scale of 1:10 could be reduced exactly to an A3 at a scale of 1:20 That is not the case with imperial papers such as legal and letter, for example.

[george013]

The beauty of metric A-series paper is that it conducted on the golden rectangle: Simply put (I hope!) The proportions of the paper are h1.414xw1. So that means if I have an A0 size it is twice the AREA of an A1, which is twice the area of an A2. What is so good about the proportions of the paper is that even if the area is halved (or doubled) the proportions of the paper remain identical. Which makes an image fitting on one size able to be blown up or reduced and still keep its scale on the paper. As one reduces the shortest dimension become the longest dimension of the next size down, as per this:

http://www.paper-sizes.com/iso-stand...es-paper-sizes

It is particularly valuable iin scaling technical drawings For example a drawing that was initially A1 at a scale of 1:10 could be reduced exactly to an A3 at a scale of 1:20 That is not the case with imperial papers such as legal and letter, for example.

The golden rectangle is based on another constant: 1.618 or the inverse 0.618. One of the magic aspects is the numbers behind the decimal point are the same. https://en.wikipedia.org/wiki/Golden_ratio or https://en.wikipedia.org/wiki/Golden_rectangle
A more informative link https://en.wikipedia.org/wiki/Paper_size

George

[Tronhard]

Absolutely right! My error and a bit of a brain meltdown.

As I recall many examples of the use of the golden ratio were incorporated into Moorish architecture, the Alhambra being one of the best examples. There is an excellent scholastic article on the nature of "sacred ratios" in the evolutions of religion, art and architecture, and their occurrences in nature.

http://www.sciencedirect.com/science...95263512000635

The A-series works on the ratio of decreasing dimensions on a constant rate of 0.7071 - as I somewhat laboriously explained earlier.That said, the A-size paper is still a thing of beauty and (IMHO) much better than the arbitrary measures of the imperial letter and legal sizes for example.

The golden rectangle is based on another constant: 1.618 or the inverse 0.618. One of the magic aspects is the numbers behind the decimal point are the same. https://en.wikipedia.org/wiki/Golden_ratio or https://en.wikipedia.org/wiki/Golden_rectangle
A more informative link https://en.wikipedia.org/wiki/Paper_size

George