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Thread: Marina Bay Sand at night

  1. #61

    Default Re: Marina Bay Sand at night

    Quote Originally Posted by nitewalk View Post
    Would it be correct to say that, the focal length depends on the lenses, whereas the cropped sensor altered the angle of view which gives a 50mm lens a 80mm equivalent view on a camera with 1.6X crop? Analogous to the cropping in PP, when we can actually get a "closed up view" by cropping?
    Yes, this is right.

  2. #62

    Default

    Quote Originally Posted by MARK1992

    However, saying that "i would get a narrower angle of view of 36mm at the widest" is not correct. "You will get a narrower angle of view of XX degrees at 24mm which is equivalent to 36mm on a full frame sensor." - Now this would be correct.

    I do suggest each party does their own research. I know I have.
    Ok I think most people understand the concept here. Probably the way of explaining is wrong. Don't think it's much of an issue

  3. #63

    Default Re: Marina Bay Sand at night

    Quote Originally Posted by wandollar View Post
    Ok I think most people understand the concept here. Probably the way of explaining is wrong. Don't think it's much of an issue
    Common misconception, yes. But while it is one, it still isn't correct.

  4. #64
    Senior Member sinned79's Avatar
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    Default Re: Marina Bay Sand at night

    Quote Originally Posted by MARK1992 View Post
    Pardon me for being pedantic, but 24mm on any camera will still be 24mm.

    You don't change the focal length just like that.
    then u are wrong.

    angle of view, if u are referring to FOV, it doesnt changes. but rather focal length is change due to crop factor (in another words, zoom in).

    a 24mm dun really appears as a 24mm on a crop vs FF body.

    crop body:

    [X]

    ff body:

    [XXX]

    u get 2 more X space on ff then crop body. in another words, 24mm on ff looks much wider but angle wise still the same even on crop.

    but the view is still the same.



    if u use 24mm on ff, what u see is what u get, exact 24mm. but using on a crop body, the equivalent focal length on a ff is 24 x 1.6 = 38mm but the FOV is still the same but u dun get the full 24mm.

    view this video and have fun!

    Video Missing
    Last edited by sinned79; 9th January 2011 at 10:39 PM.

  5. #65

    Default Re: Marina Bay Sand at night

    Quote Originally Posted by MARK1992 View Post
    Common misconception, yes. But while it is one, it still isn't correct.
    pardon my pitiful engrish and use of incorrect terms >.<

  6. #66

    Default Re: Marina Bay Sand at night

    Quote Originally Posted by kei1309 View Post
    pardon my pitiful engrish and use of incorrect terms >.<
    Completely fine. Just hope to clear things up. We are all here to learn and improve after all, aren't we?

    Quote Originally Posted by sinned79 View Post
    then u are wrong.

    angle of view, if u are referring to FOV, it doesnt changes. but rather focal length is change due to crop factor (in another words, zoom in).

    a 24mm dun really appears as a 24mm on a crop vs FF body.

    crop body:

    [X]

    ff body:

    [XXX]

    u get 2 more X space on ff then crop body. in another words, 24mm on ff looks much wider but angle wise still the same even on crop.

    but the view is still the same.



    if u use 24mm on ff, what u see is what u get, exact 24mm. but using on a crop body, the equivalent focal length on a ff is 24 x 1.6 = 38mm but the FOV is still the same but u dun get the full 24mm.

    view this video and have fun!

    Intriguing.
    Last edited by MARK1992; 9th January 2011 at 10:48 PM.

  7. #67
    Senior Member sinned79's Avatar
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    Default Re: Marina Bay Sand at night

    Quote Originally Posted by MARK1992 View Post


    Intriguing.
    i suggest u google and get your facts right again.





    no change in angle of view as claimed by you. but i did see a zoom in (aka extended focal length)



    http://www.google.com.sg/#hl=en&sour...c3e0a3c68c5846 (a google for your thoughts)

  8. #68

    Default Re: Marina Bay Sand at night

    Quote Originally Posted by sinned79 View Post
    i suggest u google and get your facts right again.





    no change in angle of view as claimed by you. but i did see a zoom in (aka extended focal length)



    http://www.google.com.sg/#hl=en&sour...c3e0a3c68c5846 (a google for your thoughts)
    Well, I can't and will not force you to believe or learn thing you don't want to, so I'll just leave it as that.

    Good day.

  9. #69
    Senior Member sinned79's Avatar
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    Default

    Quote Originally Posted by MARK1992

    Well, I can't and will not force you to believe or learn thing you don't want to, so I'll just leave it as that.

    Good day.
    Same to you.

  10. #70

    Default Re: Marina Bay Sand at night

    Best Explanations.

    Quote Originally Posted by sinned79 View Post
    then u are wrong.

    angle of view, if u are referring to FOV, it doesnt changes. but rather focal length is change due to crop factor (in another words, zoom in).

    a 24mm dun really appears as a 24mm on a crop vs FF body.

    crop body:

    [X]

    ff body:

    [XXX]

    u get 2 more X space on ff then crop body. in another words, 24mm on ff looks much wider but angle wise still the same even on crop.

    but the view is still the same.



    if u use 24mm on ff, what u see is what u get, exact 24mm. but using on a crop body, the equivalent focal length on a ff is 24 x 1.6 = 38mm but the FOV is still the same but u dun get the full 24mm.

    view this video and have fun!

    Video Missing
    Quote Originally Posted by sinned79 View Post
    i suggest u google and get your facts right again.





    no change in angle of view as claimed by you. but i did see a zoom in (aka extended focal length)



    http://www.google.com.sg/#hl=en&sour...c3e0a3c68c5846 (a google for your thoughts)

  11. #71
    Moderator nitewalk's Avatar
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    Default Re: Marina Bay Sand at night

    Confusing much. >.<

  12. #72

    Default Re: Marina Bay Sand at night

    we're not talking about focal length here but "effective focal length".

    http://www.the-digital-picture.com/c...op-factor.aspx

    nuff said....

  13. #73

    Default

    Ya "effective focal length" or "resulting focal length" sounds more right. Haha. The focal length (being a technical specification or variable of the lens) is prescribed in perspective of the lens. Think the whole thing will sound quite complicated for a newbie, but it all boils down to:

    - a 50mm lens IS a 50mm lens
    - on a full-frame body, you get 50mm as a result
    -but on a 1.5x crop body, you get 75mm as the perceived focal length through that same lens.

    Lol...

  14. #74

    Default Re: Marina Bay Sand at night

    MARK1992 is correct. The focal length of a lens is a physical characteristic of that lens. It's the same, regardless of which camera you mount it on, or if you don't mount it at all. A 50mm lens will still be a 50mm lens, when it's lying in solitude on a table.

    However, by tradition we have defined a certain focal length to go with a certain film size as "normal", in that it gives about the same field of view as the eye, or about 45° diagonal field of view.
    A Hasselblad 500C (film size 60*60mm) was normally delivered with an 80mm lens as a normal one, a Canon F-1 (film size 24*36mm) with a 50mm and the Canon Dial (18*24mm film size) with a 28mm lens. All adapted to give what's considered a normal perspective, if you look at the prints from these negatives at a convenient distance.

    The confusion came in when cameras, and their lenses, which were originally designed for 24*36mm fílm format, were instead equipped with digital sensors with sizes less than the film format. In Canon's case, the APS-C format is 15*22mm. Since this crops out a piece of the image in the middle, you get less field of view, in spite of using the same 50mm lens, compared to what you get with film, or a "full format" (in this case as full as the film format for a corresponding camera body) sensor.
    But the 50mm lens is still a 50mm lens. There is no difference at all between taking a photo with an APS-C camera with a 50mm lens, and taking the same picture with a full format camera, if you then enlarge the picture form the APS-C camera to 10*15cm, and enlarge the other picture so that you can cut out a center piece, also 10*15cm, which covers the same area as the APS-C camera saw.
    That would give you two printouts that are identical (apart from possible differences in camera sensor quality, but that's something else). Still, nobody would expect that your 50mm lens suddenly changes itself just because you put a pair of scissors in a printout, do you?

    So there is no specific coverage with a 50mm lens, nor with any other lens. It's all a question about how large part of the projected image circle behind the lens you care to register. So field of view with a certain lens depends upon the sensor size, nothing else.
    But of course, if you can't change the sensor size (some cameras do allow masking of parts of it, to make a crop camera out of a 24*36mm camera, for example), then the only other way of changing the field of view is to change the focal lenght. But this doesn't change the field of view directly either - it changes the magnification. With a shorter focal length, you get less magnification. If the lens wasn't properly compensated, you'd end up with the same picture as with your 50mm, just smaller, and with black borders. But to make any sense, the lens is designed in such a way that it compensates for the lower magnification and still projects a full image circle behind itself. The result is an image where everything is smaller, but due to that, you also get more of the view in front of you crammed into the picture. Thus a larger field of view.
    A telephoto lens is the opposite, of course.

    Summary: A lens is a lens is a lens. There is no change of the focal length, ever, until you start zooming a zoom lens. A prime will remain a 50mm (or whatever) as long as it lasts, regardless of which camera you put it on. But different film/sensor formats record more or less of the image it projects. If you then magnify the recorded images to the same printout size it will appear as if you used a different focal length. But you didn't.
    You get the same effect if you just magnify the image more, then cut away the borders.

  15. #75
    Member kwttan's Avatar
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    Default Re: Marina Bay Sand at night

    Quote Originally Posted by apersson850 View Post
    MARK1992 is correct. The focal length of a lens is a physical characteristic of that lens. It's the same, regardless of which camera you mount it on, or if you don't mount it at all. A 50mm lens will still be a 50mm lens, when it's lying in solitude on a table.

    However, by tradition we have defined a certain focal length to go with a certain film size as "normal", in that it gives about the same field of view as the eye, or about 45° diagonal field of view.
    A Hasselblad 500C (film size 60*60mm) was normally delivered with an 80mm lens as a normal one, a Canon F-1 (film size 24*36mm) with a 50mm and the Canon Dial (18*24mm film size) with a 28mm lens. All adapted to give what's considered a normal perspective, if you look at the prints from these negatives at a convenient distance.

    The confusion came in when cameras, and their lenses, which were originally designed for 24*36mm fílm format, were instead equipped with digital sensors with sizes less than the film format. In Canon's case, the APS-C format is 15*22mm. Since this crops out a piece of the image in the middle, you get less field of view, in spite of using the same 50mm lens, compared to what you get with film, or a "full format" (in this case as full as the film format for a corresponding camera body) sensor.
    But the 50mm lens is still a 50mm lens. There is no difference at all between taking a photo with an APS-C camera with a 50mm lens, and taking the same picture with a full format camera, if you then enlarge the picture form the APS-C camera to 10*15cm, and enlarge the other picture so that you can cut out a center piece, also 10*15cm, which covers the same area as the APS-C camera saw.
    That would give you two printouts that are identical (apart from possible differences in camera sensor quality, but that's something else). Still, nobody would expect that your 50mm lens suddenly changes itself just because you put a pair of scissors in a printout, do you?

    So there is no specific coverage with a 50mm lens, nor with any other lens. It's all a question about how large part of the projected image circle behind the lens you care to register. So field of view with a certain lens depends upon the sensor size, nothing else.
    But of course, if you can't change the sensor size (some cameras do allow masking of parts of it, to make a crop camera out of a 24*36mm camera, for example), then the only other way of changing the field of view is to change the focal lenght. But this doesn't change the field of view directly either - it changes the magnification. With a shorter focal length, you get less magnification. If the lens wasn't properly compensated, you'd end up with the same picture as with your 50mm, just smaller, and with black borders. But to make any sense, the lens is designed in such a way that it compensates for the lower magnification and still projects a full image circle behind itself. The result is an image where everything is smaller, but due to that, you also get more of the view in front of you crammed into the picture. Thus a larger field of view.
    A telephoto lens is the opposite, of course.

    Summary: A lens is a lens is a lens. There is no change of the focal length, ever, until you start zooming a zoom lens. A prime will remain a 50mm (or whatever) as long as it lasts, regardless of which camera you put it on. But different film/sensor formats record more or less of the image it projects. If you then magnify the recorded images to the same printout size it will appear as if you used a different focal length. But you didn't.
    You get the same effect if you just magnify the image more, then cut away the borders.

    Wow! Very detail piece of information/explanation. You create a new CS account just to explain this?
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  16. #76
    Moderator nitewalk's Avatar
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    Default Re: Marina Bay Sand at night

    Quote Originally Posted by sinned79 View Post
    Same to you.
    AFAIK from Physics, focal length is a characteristic of a piece of glass that is called a lens and in a camera lens, this is generally made up of a few glasses. The focal length then depends on how far apart of these glasses and what glasses are used. The focal length indicates how strongly the lens converges light. When we say "the 50mm lens on crop body has an equivalent focal length of 80mm on a FF", the focal length do not change, its just that the resultant image produced by a 50mm on 1.6X crop camera is similar to a 80mm on a FF. However, i say they still have different focal length, because the 50mm still has a different ability to focus/converge light rays compared to the 80mm.

    Let's say a 50 mm lens. This indicates its ability to converge light rays into the camera. My question to all: how can the lens' ability to converge light change, just by mounting it from a FF to a crop when the ability to focus light rays is due to the glass elements and not the sensor? The 1.6 crop factor comes from the sensor being smaller.

    From a Physics point of view, mark is not wrong. However, sinned79 is not wrong. Sinned79's understanding is analogous to how we crop a photo, say around a particular subject. Notice how the subject appear magnified after cropping? That magnification is analogous to the crop factor in a sensor. Essentially, the image that comes into a crop body camera does not change because it is still the same lens, but what your crop body camera does is to do what Photoshop does, i.e. cropping.
    Last edited by nitewalk; 10th January 2011 at 09:24 AM.

  17. #77
    Senior Member sinned79's Avatar
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    Default Re: Marina Bay Sand at night

    Quote Originally Posted by nitewalk View Post
    AFAIK from Physics, focal length is a characteristic of a piece of glass that is called a lens and in a camera lens, this is generally made up of a few glasses. The focal length then depends on how far apart of these glasses and what glasses are used. The focal length indicates how strongly the lens converges light. When we say "the 50mm lens on crop body has an equivalent focal length of 80mm on a FF", the focal length do not change, its just that the resultant image produced by a 50mm on 1.6X crop camera is similar to a 80mm on a FF. However, i say they still have different focal length, because the 50mm still has a different ability to focus/converge light rays compared to the 80mm.

    Let's say a 50 mm lens. This indicates its ability to converge light rays into the camera. My question to all: how can the lens' ability to converge light change, just by mounting it from a FF to a crop when the ability to focus light rays is due to the glass elements and not the sensor? The 1.6 crop factor comes from the sensor being smaller.

    From a Physics point of view, mark is not wrong. However, sinned79 is not wrong. Sinned79's understanding is analogous to how we crop a photo, say around a particular subject. Notice how the subject appear magnified after cropping? That magnification is analogous to the crop factor in a sensor. Essentially, the image that comes into a crop body camera does not change because it is still the same lens, but what your crop body camera does is to do what Photoshop does, i.e. cropping.
    I always tries to explain things simpler to those who just step into the whole of DSLR.

    http://www.clubsnap.com/forums/showp...4&postcount=30

    anyway i never use the word CHANGE at all in my post above. It is use by MARK1992 in the below post.

    http://www.clubsnap.com/forums/showp...1&postcount=49

    Guess he is the one causing more confusion.

    I think my explanation is clear enough to TS till he stepped in to try "correct" me.

    He is also terribly wrong about angle of view.

    http://www.clubsnap.com/forums/showp...8&postcount=55

    Like he say, 24mm is still the 24mm lens so is the Angle of View (also known as FOV - Field of View) cos it is still the same lens.

    Definition:
    http://en.wikipedia.org/wiki/Angle_of_view
    Last edited by sinned79; 10th January 2011 at 10:11 AM.

  18. #78

    Default Re: Marina Bay Sand at night

    Why are we all arguing over technical terms? What is important is the idea is gotten across. Knowing exactly how the lens converges light onto your sensor does not help you take great pictures.

  19. #79

    Default Re: Marina Bay Sand at night

    Quote Originally Posted by brapodam View Post
    Knowing exactly how the lens converges light onto your sensor does not help you take great pictures.
    This should not be the focus of photography, but knowing how light and your camera interact can help in the process of taking a photo.
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    Default Re: Marina Bay Sand at night

    Quote Originally Posted by candycaine View Post
    This should not be the focus of photography, but knowing how light and your camera interact can help in the process of taking a photo.
    And also, depending on how they converge, like in the case of comparing a 501.4 on crop and 85f1.4 on FF, the main big difference will be DOF.
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