F2.0 vs F2.4

Discussion in 'iPhone' started by Semester, Sep 9, 2013.

  1. Semester macrumors regular

    Semester

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    Oct 27, 2011
    #1
    As you might know Apple is rumored to change the aperture from 2.4 to 2.0.
    I am rather lost on photography and have basically no idea what this means but what I understand is that a smaller number is better. Anyhow, can someone give a man with little knowledge of the field an idea how big a difference this rumored change is and if it alone will have any substantial impact on the quality of photos taken?

    Fom what i read in the tech press it is mostly depicted as a minor change.
     
  2. maflynn Moderator

    maflynn

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    #2
    Technically its a half stop faster :)

    All it means is at f2.0, there's more light coming into the sensor, so it can take a picture faster or perform better in low light conditions. All things being equal, larger apertures (smaller numbers) mean you can increase the shutter speed (less blurry pictures.)
     
  3. Jimmy James macrumors 68040

    Jimmy James

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    #3
    F2.8 is a full stop slower than F2.0. Therefore F2.4 is roughly a half stop as mentioned by the previous poster. This means that F2.0 can use a shutter speed 50% faster to get the same exposure. This helps to eliminate camera shake and motion blur.
     
  4. wermy macrumors regular

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    Apr 15, 2013
    #4
    But how much difference is it in the amount of light? I don't know a ton about this stuff, but I thought it wasn't a linear scale (i.e, 2.0 is not actually 17% more light than 2.4, but more like 30% or something).

    Edit: Jimmy James answered my question and he didn't even know it. Thanks!
     
  5. maflynn Moderator

    maflynn

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    #5
    As Jimmy James posted, the shutter speed can operate at 50% faster.
     
  6. -js- macrumors regular

    -js-

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    #6
    If the ISO (sensitivity) of the 5S's sensor is the same a the 5, then we can answer the question about how much light you need.

    ISO is equivalent to how sensitive the film is on a film camera--how "high speed" it is. ISO 100 to 200 is a full stop worth of difference. 200 to 400 same, and so on.

    For digital cameras, their sensor has a certain sensitivity, depending on pixel size, sensor size, type of sensor, etc. This is why a higher mega-pixel rating is FAR from being all you need to know about a camera. A higher MP with a lower sensitivity and a smaller aperture = a WORSE CAMERA, no matter how many more MP it has. Apple KNOWS this, thankfully. So the 5S camera sensor sensitivity almost certainly will be at least as good, I suspect, but it may be even better. In which case, the combination of increased sensitivity and increased aperature size might add up to even more than a half stop of difference.

    In any case, even a half-stop is significant when you're down in the low-light threshold of your equipment and are holding it by hand. I've been using a dSLR for years, and for the first two I was using the kit lens and wondering why in the heck I couldn't get decent pictures indoors without using the flash. THEN I discovered prime lenses. I got a 50mm f/1.4 and was blown away by what I could do. Last year I added a 35 mm f/2.0 for the wider field of view. These aperatures combined with an ISO of 800 or 1600 allow me to take nice bright photos INSIDE in winter in a not-so-bright house. I took a bunch of photos last Thanksgiving on an overcast winter day and they came out great. Lots of Bokeh (out of focus behind subject) and a little bit grainy, but still quite nice, and no flash artifacts and harshness.

    I'm told by my professional photographer friend that I need to learn to use a flash properly, and to invest in a decent flash--and I'm sure she's right--but I still won't ever go back to a lens with a small aperture, like f/3.2 or something. Not unless I get a new dSLR with a lot more sensitivity (i.e. can go to higher ISO).

    Anyway, this is why the iPhone cameras are so good. Apple doesn't design them based on just a single parameter, like mega pixels.
     
  7. chrmjenkins macrumors 603

    chrmjenkins

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    #7
    And OIS can further help with that. Quite a few phones feature it these days.
     
  8. Jimmy James macrumors 68040

    Jimmy James

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    Oct 26, 2008
    #8
    That would be very nice.
     
  9. Michael CM1 macrumors 603

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    Feb 4, 2008
    #9
    It occurs to me that this F number series for cameras is about as confusing as the earthquake magnitude scale. You'd think there's little difference between a 7.9 and 8.0 magnitude earthquake, but it's actually quite a difference.

    Someone in marketing should really get in charge of things like this. I remember AMD doing that when they went away from the megahertz/gigahertz ratings because laypeople would see "Pentium 1 GHz" versus "Athlon 900 MHz" and think the 1GHz is better because of just simple math. I've got a 3.06 GHz Core i3, which I know isn't as good as a quad-core CPU at maybe 2.4 GHz.

    Thank you to the photog nerds out there for knowing and explaining. I thought F2.4 would be a larger light opening than F2.0, but you guys apparently know better. :)
     
  10. iBreatheApple macrumors 68020

    iBreatheApple

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    #10
    I'm no photographer either but it was dumbed down to me by basically saying the lower the aperture, the more blurred the background will be. This is good because the foreground is much more focused and it makes the photo look more professional. I'm sure there's much more to it but there's an elementary explanation for you.
     
  11. Lucille Carter macrumors 65816

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    Jul 3, 2013
    #11
    Yep, small F number is better.

    Think of it this way, at f1.0 the same amount of light entering the lens exits on the back to hit the sensor. It is all about the physics of light and efficiency of lenses.
     
  12. gerbilbox, Sep 10, 2013
    Last edited: Sep 10, 2013

    gerbilbox macrumors regular

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    #12
    The reason why the "smaller" f-stop number has more light is that when we say f2.0 and f2.4, it's actually written as f/2.0 and f/2.4. So as a fraction, 1/2.0 is a larger number than 1/2.4. Many people omit the slash as a shorthand.

    It may seem confusing but I've taught many beginning photographers and they pick this up quickly after practicing with a few photos, and the concept is the same regardless of the camera. It's similar to shutter speed, which is also a fraction, so 1/30 of a second exposure has more light than 1/60 sec.
     
  13. whitmanjg macrumors member

    whitmanjg

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    Durham, NC
    #13
    kind of, it actually means the field of focus is shallower, so whether you focus on the foreground, middleground, or background, there will be a smaller area (depth-wise) that is in focus, making the rest of the image out of focus.

    [​IMG] small aperture(=larger number)

    [​IMG] large aperture (=smaller number)


    however, as this relates to the iphone, the difference between 2.0 and 2.4 isnt that much in terms of depth of field.
     
  14. robbieduncan Moderator emeritus

    robbieduncan

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    #14
    This is not true. An f/1.0 lens has a diaphragm diameter equal to the focal length of the lens. So an f/1.0 4mm lens has a maximum aperture of 4mm diameter. A f/1.0 8mm lens 8mm and so on. The way the maths work out is that f-stops allow an equivalence of light independent of focal length: for the same ISO and f-stop you need the same shutter speed to get the same metered exposure regardless of focal length.

    It's not about efficiency of transmission: that would be a t-stop (which is pretty much always a little slower than the f-stop). It's about the size of pupil that the lens has to allow light in.
     
  15. borgqueenx macrumors 65816

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    #15
    why would we want 50% more shutter speed. go open your iphone 5 and keep ramming that capture button. it goes as fast as you can ram your finger against that button.
     
  16. maflynn Moderator

    maflynn

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    #16
    Faster shutter speeds help against motion blur, i.e., the phone moving while snapping and performance in lower light situations.
     
  17. whitmanjg macrumors member

    whitmanjg

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    #17
    shutter speed isnt about how quickly the phone responds to your touch, its about how much time the lens stays open, allowing the light to come in to make the image. faster shutter speed = less blur
     
  18. borgqueenx macrumors 65816

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    #18
    hmm, so if i understand correctly if you make a picture of a moving object, this becomes less blurry then before?

    EDIT: never mind thanks maflynn:)
     
  19. takeshi74 macrumors 601

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    Feb 9, 2011
    #19
    No need to change everything in the world for those that can't be bothered to read up. Those that can't be bothered probably don't care anyway.
     
  20. Namji macrumors 6502a

    Namji

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    #20
    OMG... learn about Photography !!
     
  21. Michael CM1 macrumors 603

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    Feb 4, 2008
    #21
    As a copy editor, arrgh at the omission of a slash that is apparently important as hell. Thanks again for the explanation because I still can't understand aperture very well even though a photographer has explained it to me.
     
  22. borgqueenx macrumors 65816

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    #22
    only 0,2 increase. no 0,4 like someone thought^^
     
  23. whtrbt7 macrumors 6502a

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    Jun 8, 2011
    #23
    f/2.2 is still really awesome. They also have a new 5 element lens which is pretty amazing. Add burst mode and slow motion capture and it will replace most point and shoot cameras on the market.
     
  24. Pompiliu macrumors 6502a

    Pompiliu

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    Apr 22, 2012
    #24
    Do you even know how a camera works?
    Jesus!
    [​IMG]
     
  25. borgqueenx macrumors 65816

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    #25
    whats different about those 5 element lenses?
     

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