Aspect Ratio...

Discussion in 'Photography' started by J, Nov 19, 2011.

  1. J

    J Guest

    I'm probably going to kick myself for asking this, but.....

    I recently bought a small digicam with 18mm wide-angle capability, a Samsung
    PL120 to be exact. I also have a Canon EOS 300D which I use with a 18-55mm
    lens. I know about the 300D's cropping factor, and this comes out to 28mm
    but....'why is it that when I take 'wide-angle' shots with both these
    cameras, the 'aspect ratio' is different? The 300D gives me a 6 x 4 ratio,
    but the Samsung gives more of a 4 x 3 ratio? In fact, I have noticed this
    when looking at photos taken by many recent digicams who 'boast' 28mm
    wide-angle. Why are these digicam shots almost square (4 x 3) and the DSLRs
    are more 'rectangular' (6 x 4)? I really don't understand why there is this
    difference.

    J
     
    J, Nov 19, 2011
    #1
    1. Advertisements

  2. J

    Robert Coe Guest

    : I'm probably going to kick myself for asking this, but.....
    :
    : I recently bought a small digicam with 18mm wide-angle capability, a Samsung
    : PL120 to be exact. I also have a Canon EOS 300D which I use with a 18-55mm
    : lens. I know about the 300D's cropping factor, and this comes out to 28mm
    : but....'why is it that when I take 'wide-angle' shots with both these
    : cameras, the 'aspect ratio' is different? The 300D gives me a 6 x 4 ratio,
    : but the Samsung gives more of a 4 x 3 ratio? In fact, I have noticed this
    : when looking at photos taken by many recent digicams who 'boast' 28mm
    : wide-angle. Why are these digicam shots almost square (4 x 3) and the DSLRs
    : are more 'rectangular' (6 x 4)? I really don't understand why there is this
    : difference.

    Traditionally, the sensors in cheaper digital cameras have been made with a
    4:3 aspect ratio, that of the old CRT television sets and VGA monitors. The
    sensors in DSLRs have customarily had 3:2 sensors, matching the aspect ratio
    of most 35mm film cameras. There are exceptions, but old traditions die hard.
    One possible reason, though unrelated to its origin, for keeping the 3:2
    aspect ratio in DSLRs is that the shorter vertical dimension may make it
    easier to keep the mirror from hitting something when it swings out of the
    way.

    Bob
     
    Robert Coe, Nov 19, 2011
    #2
    1. Advertisements

  3. J

    Pete A Guest

    On the UK website the PL120 it claimed to have 4320x3240 pixels = 4:3
    aspect ratio = 1.333 and is nearer to a square than the traditional 135
    and APS-C (Canon EOS 300D) 6x4 formats, which have an aspect ratio of
    1.5.

    The lens is claimed to have a 135 format equivalent of 26-130 mm.
    Remember that the equivalent is usually calculated based on the
    diagonal angle-of-view not the width or height of the view. Here are
    the wide-angle equivalents:

    Camera Width Height Actual
    ---------------------------
    PL120 27 mm 24 mm 4.7 mm
    300D 29 mm 29 mm 18 mm

    The widths are pretty close. If you send images from each camera for
    printing at 6x4 inches your 300D images will fit whereas your PL120
    images will have to be cropped top and bottom.

    The PL120 4:3 aspect ratio was standard television format and has been
    popularized by the micro four thirds format cameras. However, let's not
    forget that this exactly fits 8x6 inch prints, which have become
    popular since the price has dropped.

    5:4 is another common aspect ratio because it produces 10x8 and 20x16
    inch prints.

    To get 8x6 or 10x8 inch prints from your 300D the sides have to be cropped.

    Square format cameras remain useful because there is no need to turn
    the camera through 90 degrees for portrait-mode shots.

    Horses for courses, as they say.
     
    Pete A, Nov 19, 2011
    #3
  4. J

    Pete A Guest

    There are quite a few lenses that would be damaged by a larger height mirror.

    Perhaps a good reason for keeping the 3:2 format is so that APS-C/DX
    cameras make darned good backup bodies for full frame users. Don't know
    about Canon equivalents, but the Nikon D300/700/D3 series are very easy
    to switch between - learn one and the others are intuitive apart from
    the crop factor.

    I do think that the ever increasing number of pixels is making
    rectangular format sensors pointless. We'd be better off having aspect
    ratio and landscape/portrait mode selectable via buttons. Some cameras
    already have switchable aspect ratio. Shape-shifting lens hoods and
    flash heads could be fun.
     
    Pete A, Nov 19, 2011
    #4
  5. J

    Robert Coe Guest

    : On 2011-11-19 03:56:06 +0000, Robert Coe said:
    :
    : > : I'm probably going to kick myself for asking this, but.....
    : > :
    : > : I recently bought a small digicam with 18mm wide-angle capability, a Samsung
    : > : PL120 to be exact. I also have a Canon EOS 300D which I use with a 18-55mm
    : > : lens. I know about the 300D's cropping factor, and this comes out to 28mm
    : > : but....'why is it that when I take 'wide-angle' shots with both these
    : > : cameras, the 'aspect ratio' is different? The 300D gives me a 6 x 4 ratio,
    : > : but the Samsung gives more of a 4 x 3 ratio? In fact, I have noticed this
    : > : when looking at photos taken by many recent digicams who 'boast' 28mm
    : > : wide-angle. Why are these digicam shots almost square (4 x 3) and the DSLRs
    : > : are more 'rectangular' (6 x 4)? I really don't understand why there is this
    : > : difference.
    : >
    : > Traditionally, the sensors in cheaper digital cameras have been made with a
    : > 4:3 aspect ratio, that of the old CRT television sets and VGA monitors. The
    : > sensors in DSLRs have customarily had 3:2 sensors, matching the aspect ratio
    : > of most 35mm film cameras. There are exceptions, but old traditions die hard.
    : > One possible reason, though unrelated to its origin, for keeping the 3:2
    : > aspect ratio in DSLRs is that the shorter vertical dimension may make it
    : > easier to keep the mirror from hitting something when it swings out of the
    : > way.
    :
    : There are quite a few lenses that would be damaged by a larger height mirror.
    :
    : Perhaps a good reason for keeping the 3:2 format is so that APS-C/DX
    : cameras make darned good backup bodies for full frame users. Don't know
    : about Canon equivalents, but the Nikon D300/700/D3 series are very easy
    : to switch between - learn one and the others are intuitive apart from
    : the crop factor.

    That's true in the Canon world as well. There's a lot of similarity of
    controls across the DSLR product lines; and the last I looked, that similarity
    extended into the P&S lines as well.

    : I do think that the ever increasing number of pixels is making
    : rectangular format sensors pointless. We'd be better off having aspect
    : ratio and landscape/portrait mode selectable via buttons. Some cameras
    : already have switchable aspect ratio. Shape-shifting lens hoods and
    : flash heads could be fun.

    The problem is that the variability of aspect ratios is an illusion. All
    you're doing is sacrificing some of the pixels when you select an aspect ratio
    that doesn't match the shape of the sensor. In principle you might be able to
    speed up repetitive shooting slightly by designing the circuitry so that the
    pixels that aren't being used aren't scanned. But that would probably drive up
    the price, and I'd be surprised to learn that any manufacturer has found it to
    be worth doing.

    Bob
     
    Robert Coe, Nov 19, 2011
    #5
  6. Some issues:

    1. IHV's will almost certainly move to mirrorless cameras soon.

    2. Viewable aspect ratio integrating with learned shooting habits.
     
    Charles E. Hardwidge, Nov 19, 2011
    #6
  7. J

    dadiOH Guest

    The focal length of a lens has nothing to do with the aspect ratio. A lens
    is transmitting a circular image; that image must be large enough to cover
    the longest dimension of the film/sensor; any smaller size - of whatever
    ratio - can be used.

    A ratio of 4:3 is the standard 35mm format; a ratio of 1.5:1 is double frame
    35mm. Movie cameras run film vertically which gives an image of 1" x3/4"
    (4:3 ratio) on 35mm film; most 35mm still cameras run film horizontally
    which gives an image size of 1.5" x 1" on the same film. In both cases, a
    28mm lens would give the same perspective and the same depth of field but if
    a movie 28mm were to be used on a still camera the coverage of the lens
    would (probably) be insufficient to cover the field and would vignette;
    conversely, a still 28mm lens could be used on a movie camera assuming it
    could be fitted.

    --

    dadiOH
    ____________________________

    dadiOH's dandies v3.06...
    ....a help file of info about MP3s, recording from
    LP/cassette and tips & tricks on this and that.
    Get it at http://mysite.verizon.net/xico
     
    dadiOH, Nov 19, 2011
    #7
  8. J

    Pete A Guest

    I think having a brand generic interface is a really good idea.
    I agree with you that variable aspect ratio is an illusion, but it's
    very handy to have the viewfinder settable to the target format rather
    than the sensor format. The D3 has a 5:4 option because many pros shoot
    for 10x8 or 20x16 inch prints. The Panny G1, G2 and G3 offer 16:9, 4:3,
    3:2, and 1:1 ratios, but lack 5:4 for some strange reason. The Oly E-30
    has 9 aspect ratios including 5:4.

    Oly has the right idea. There is no point in having a camera that
    outputs very nice JPEGs, but not framed as the photographer intended -
    such a device isn't a modern camera, it's just the front end for an
    image editor.

    The OP raised a very good point about the increasingly common 4:3
    format. Many people don't realize that their shiny new camera has a
    format incompatible with 6x4 inch prints until they get their first set
    printed. I remember this happening years ago when people were enticed
    to have their films printed on bigger 7x5 inch prints - it led to the
    introduction of 7 1/2 x 5 inch prints.

    To anyone not familiar with aspect ratios, the standard print sizes
    must seem absurd as must the fact that some sizes are quoted for
    landscape and others are reversed for portrait.

    I'm glad to find that attempts to quote all print sizes only in
    millimetres or cm wasn't very popular. E.g. asking for 152x203 mm
    prints would be annoying.
     
    Pete A, Nov 19, 2011
    #8
  9. J

    Alan Browne Guest

    Most DSLR's follow the old 35mm ratio of 3:2.

    4/3 format (and other digitals) use a 4:3 ratio.

    Note that there are historical reasons for 4:3 which is 1/2 of a 6x9
    frame, a common medium format a.r.

    Some MF digitals, such as Hasselblad, also use 4:3.

    In the end, it's either you shoot for the aspect ratio of the camera or
    you crop for the aspect ratio desired.

    My camera has a 16:9 mode but I discovered that the raw file is the full
    sensor image regardless of that mode so I don't use it. I crop the
    image to the desired output.
     
    Alan Browne, Nov 19, 2011
    #9
  10. J

    Chemiker Guest

    Permit me to disagree. Divide 6:9 by 3 and you get 2:3, not 3:4 (which
    is so-called 4:3). 6:9 cm backs for 4x5 cameras give you the same
    aspect ratio as the 35mm does, which is 1:1.5.

    What I find fascinating is that (it seems) no one ever used 1:1.618,
    which is the so-called "golden" or "perfect" mean (phi), also called
    the golden ratio. See more on composition within phi at:

    http://en.wikipedia.org/wiki/Golden_ratio

    9:16 has an a.r. or 1:1.77.
    Alex
     
    Chemiker, Nov 19, 2011
    #10
  11. J

    Alan Browne Guest

    645 (4:3) is 1/2 of a 6x9 frame. Where you get 'divide by 3' is a
    mystery for which I don't want an answer.
     
    Alan Browne, Nov 19, 2011
    #11
  12. J

    gordo Guest

    Lowest common denominator, for those who do.

    Gordito

    "Alan Browne" wrote in message

    645 (4:3) is 1/2 of a 6x9 frame. Where you get 'divide by 3' is a
    mystery for which I don't want an answer.
     
    gordo, Nov 19, 2011
    #12
  13. J

    Pete A Guest

    Half of a 6x9 cm frame (2:3 ratio) is 6x4.5 cm (645 medium format) =
    4:3 ratio, as Alan said.
    It seems to me that the golden section is used more in relating
    elements on a page than the paper size itself. See 2.3 Tschichold and
    the golden section:

    <http://en.wikipedia.org/wiki/Canons_of_page_construction>

    and I found this interesting about Web page design:

    <http://www.smashingmagazine.com/2010/02/09/applying-mathematics-to-web-design/>
     
    Pete A, Nov 19, 2011
    #13
  14. That's the shape of the sensors in the cameras; it's different.

    "Why" would be a discussion about why each company chose the particular
    shape sensor they did. The DSLRs started (and are still) for the
    purpose of using the existing collection of lenses intended for 35mm
    film, so they've maintained that aspect ratio (the 2:3 ratio; a 35mm
    still negative is 24mm x 36 mm. (That, in turn, was chosen because it
    was the size of two 35mm motion picture fames plus the space between
    them. 35mm still cameras were designed to use the film already in wide
    production for motion picture use.)

    I think the choice of less rectangular ratios for many P&S digital
    cameras is a statement that they think the 35mm aspect ratio has always
    been less than ideal.
     
    David Dyer-Bennet, Nov 19, 2011
    #14
  15. Serious cameras need more controls than consumer cameras, though. And
    controls are expensive.

    At least in the Nikon line, you lose the second control dial after the
    top two levels, for example. And those two dials are the two most-used
    controls on the camera (in manual mode one is shutter speed and one is
    aperture).
    Or, back in the film era, cameras like the Hasselblad shot "6x6"
    negatives. Most people cropped to one of the rectangular print sizes
    most of the time, though people did also print them square sometimes.
    Well, of course. Any serious camera is just the front-end for an image
    editor. As Ansel Adams said, the negative is the score, the print is
    the performance. If you're just showing people jpegs straight out of
    your camera, you're not giving your images a fair shake at being
    appreciated.
    The standard print sizes never fit standard film sizes very well during
    my lifetime.

    The 4x5, 8x10, 11x14 sizes started out being film sizes and also print
    sizes, when people contact-printed from big negatives. But 120 roll
    film started out shooting mostly 2.25x3.25 and 2.25x2.25, neither of
    which fit any standard print paper. And then 35mm came along and made
    it even worse.

    The 4x6 print came along rather late in the life of 35mm; until then
    there was no size that just fit.
    Even the native metric sizes (A series, like A4 and so forth) are
    hideous numbers to learn and remember (since the whole series is based
    on irrational numbers, they can't possibly end up neat).
     
    David Dyer-Bennet, Nov 19, 2011
    #15
  16. No.

    A 35mm negative is 24mm x 36mm, the ratio is 2:3.
     
    David Dyer-Bennet, Nov 19, 2011
    #16
  17. Not actually very common. It was more common as a folding snapshot
    camera format. The common MF formats are 6x4.5, 6x6, and 6x7, with 6x9,
    6x12, and 6x17 being much less common.
     
    David Dyer-Bennet, Nov 19, 2011
    #17
  18. Sounds a bit dick wavey/snobbish.
     
    Charles E. Hardwidge, Nov 19, 2011
    #18
  19. J

    dadiOH Guest

    Yes. Go back and read what I wrote.

    --

    dadiOH
    ____________________________

    dadiOH's dandies v3.06...
    ....a help file of info about MP3s, recording from
    LP/cassette and tips & tricks on this and that.
    Get it at http://mysite.verizon.net/xico
     
    dadiOH, Nov 19, 2011
    #19
  20. J

    Savageduck Guest

    I believe when Alan said "common" he was referring to 645 (6x4.5) which
    is 4:3 and effectively half of a 6x9, or more exactly a 6x9 cut at 4.5
    on the long axis resulting in a 6x4.5.
     
    Savageduck, Nov 19, 2011
    #20
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.