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Thread: Crop factor with ISO, aperture and focal length

  1. #1
    Senior Member UncleFai's Avatar
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    Default Crop factor with ISO, aperture and focal length

    https://www.youtube.com/watch?v=DtDotqLx6nA&sns=fb

    Friends debating the correctness (especially the explanation) of this video. Can the experts here weigh in? Are the manufacturers lying?

  2. #2

    Default Re: Crop factor with ISO, aperture and focal length

    What Tony said is valid. But logically an f2.8 lens is still an f2.8 lens. Which means an mft lens gather the same light as a FF lens at 2.8. Yes there's the crop factor and all but to my understanding, it only applies to the DOF and focal length.

    I wouldn't say the manufacturers are lying but can you imagine if an mft lens was stated as 5.6 but it gathers the same light as an 2.8 FF lens? That would be confusing to the masses.

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  3. #3

    Default Re: Crop factor with ISO, aperture and focal length

    Strictly speaking the manufacturers are not lying. However they are not telling the complete truth either.

    I think the problem arises really due to the reduction in sensor size, i.e. you take a photo on a smaller sensor and then enlarge it to the same size as an image taken from a larger sensor.

    It might be unintuitive in the digital age since image size is usually rendered in terms of pixels instead of actual physical dimensions (like length x width) like during the days of film.

    Therefore perhaps it might be easier to consider the following example. Shooting an image on a piece of "full frame" 36mm x 24mm film, and then trying to shoot the same image (field of view etc) on a piece of APS-C 25.1mm x 16.7mm film (this film size actually existed!) and then enlarging it to 36mm x 24mm. You would notice the same effects Tony has mentioned coming into play due to the mathematics involved in shooting on a smaller film size and then enlarging it.
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  4. #4
    Senior Member Nikonzen's Avatar
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    Default Re: Crop factor with ISO, aperture and focal length

    Not all pixels are created equal...basic physics bros.
    Expand your mind or get left behind

  5. #5

    Default

    What is the question?

  6. #6
    Moderator catchlights's Avatar
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    Default

    How does this help in your photography?
    Shoot to Live, Live to Shoot
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  7. #7

    Default Re: Crop factor with ISO, aperture and focal length

    Quote Originally Posted by catchlights View Post
    How does this help in your photography?
    To understand that different system has its own benefit I supposed?

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  8. #8
    Moderator Octarine's Avatar
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    Default Re: Crop factor with ISO, aperture and focal length

    Quote Originally Posted by Ha Zu Ni Za View Post
    To understand that different system has its own benefit I supposed?
    That's the same as debating the pros and cons of 90 horse powers versus 150 horse powers when fetching your parents for dinner. All what matters to them is a safe as smooth trip.
    In photography, many factors are more important, relevant and visible than the philosophy of 'real f/2.8' on different systems.
    EOS

  9. #9
    Moderator catchlights's Avatar
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    Default

    Quote Originally Posted by Ha Zu Ni Za View Post
    To understand that different system has its own benefit I supposed?

    Sent from my SM-N9005 using Tapatalk
    Photography is about lighting, composition, capture the moment, the emotion, telling a story, if you think that really help you to get these, than please go ahead to learn all the systems.
    Shoot to Live, Live to Shoot
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  10. #10

    Default Re: Crop factor with ISO, aperture and focal length

    Quote Originally Posted by catchlights View Post
    Photography is about lighting, composition, capture the moment, the emotion, telling a story, if you think that really help you to get these, than please go ahead to learn all the systems.
    I don't know why you sound hostile, sir. But I'm just giving a general answer to a topic that has countless of debates. And this is a forum after all. Yes, I do agree that apart from technical stuffs, there are things that make photography an art itself.

    I apologised if I sound like a Mr Knows It All. But a man of your calibre and experience is way better than to be telling me to "shove it up all in my ass because I'm a newbie"

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  11. #11

    Default Re: Crop factor with ISO, aperture and focal length

    Chill, everyone is right here

    Differences just from which angle you see the issue from
    (if really want to argue, maybe I can suggest that knowing this, you can know the 'quantity' of lighting, and 'depth of field' considerations for composition )

    For those who like a longer read hehe:
    http://www.dpreview.com/articles/266...-should-i-care

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