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Thread: Controlling the depth of view ...how ?

  1. #1
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    Default Controlling the depth of view ...how ?

    Hi all,

    I would like to know how to control the depth of view in manual mode. I have often read articles which says that the aperture must be big if one wants 'bokeh' effect and small apearture for landscape or whole picture to be sharp.

    While playing with my camera, I find that it is the manual ring which actually controls the DOV: I can actully control if I want the background, forground or the overall picture to be blur by just adjsuting the manual ring.

    Can somenody correct me and give me pointer regarding depth of view ?

    Thanks

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    Default Re: Controlling the depth of view ...how ?

    Quote Originally Posted by singdude
    Hi all,

    I would like to know how to control the depth of view in manual mode. I have often read articles which says that the aperture must be big if one wants 'bokeh' effect and small apearture for landscape or whole picture to be sharp.

    While playing with my camera, I find that it is the manual ring which actually controls the DOV: I can actully control if I want the background, forground or the overall picture to be blur by just adjsuting the manual ring.

    Can somenody correct me and give me pointer regarding depth of view ?

    Thanks
    The thing to remember about DOV is, the smaller the aperture number the shallower the DOV and the bigger the number the deeper/longer the DOV.
    If you are shooting a portrait of someone and also want to include a background, if you focus on the person and shoot at f4, your background will be blur. But if you focus on the person and shoot at f22, you can be sure the person and the background would be sharp too.

    Just in case you're not aware, small aperture number means a big aperture hole while a big aperture number means a small aperture hole.
    Sometimes during low-light conditions, when you have no choice but to open up the aperture to get the right exposure, the 'third' rule can help maximize DOV even if the aperture you are using is only f4. Focusing a third of the way between the subject and the background yields the maximum DOV for whichever aperture you use. In other words, if your subject is standing 4 meters from you and the background is 16 meters away, your point of focus, to get the max DOV, should be the 8 meters point. By doing this, instead of only getting your subject sharp with f4, the chances of getting both subject and background sharp is higher, depending on the distance.
    Last edited by Heartshape; 3rd January 2006 at 05:14 AM.

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    Default Re: Controlling the depth of view ...how ?

    Thank you, Heartshape for taking a time to answer my query.

    Could you shed some light about the manual ring which is used to focus the background or forground ? Does it have any play in controlling the depth of view ?

    I am very confused on this.

    Thank you.


    Quote Originally Posted by Heartshape
    The thing to remember about DOV is, the smaller the aperture number the shallower the DOV and the bigger the number the deeper/longer the DOV.
    If you are shooting a portrait of someone and also want to include a background, if you focus on the person and shoot at f4, your background will be blur. But if you focus on the person and shoot at f22, you can be sure the person and the background would be sharp too.

    Just in case you're not aware, small aperture number means a big aperture hole while a big aperture number means a small aperture hole.
    Sometimes during low-light conditions, when you have no choice but to open up the aperture to get the right exposure, the 'third' rule can help maximize DOV even if the aperture you are using is only f4. Focusing a third of the way between the subject and the background yields the maximum DOV for whichever aperture you use. In other words, if your subject is standing 4 meters from you and the background is 16 meters away, your point of focus, to get the max DOV, should be the 8 meters point. By doing this, instead of only getting your subject sharp with f4, the chances of getting both subject and background sharp is higher, depending on the distance.

  4. #4
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    Default Re: Controlling the depth of view ...how ?

    Quote Originally Posted by singdude
    Thank you, Heartshape for taking a time to answer my query.

    Could you shed some light about the manual ring which is used to focus the background or forground ? Does it have any play in controlling the depth of view ?

    I am very confused on this.

    Thank you.
    the manual ring is meant for focusing and not for adjustment of depth of field. Its like when you are slightly myopic. your eyes are capable of focusing on nearby things up to a certain short distance. They do this by changing the shape of you lens to change the focal length. But if you decide to focus of a further subject, you will tend to squint or make your eyes smaller which tend to make the image sharper. The image becomes sharper not because your eye lens was able to focus on the subject but because squinting makes a wider area of subject, near and far, come into focus. This is like adjusting the cameras aperture.

    Perhaps this might make things clearer for you. If you made 10 people stand in a straight line, from front to back, and you focused on person in the middle either with the manual focus ring (or depressing the shutter halfway - if you have an AF camera). If you set the aperture to the smallest number and took a picture, you will notice (if the people were spaced relatively far apart) that only the middle person is in focus. Now if you maintain the focus and just adjust the aperature to a smaller number and took the same photo, you will start to notice that even though you are focusing on just one person, more people in front and back become focused as well, as your aperture number increases. Try it and see.

    Take note that, you have to take the pictures to notice the difference, unless your camera comes with a depth of field preview function. This is because the camera always shows the smallest aperture number through the viewfinder to provide the brightest image for framing and focusing.

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    Default Re: Controlling the depth of view ...how ?

    Quote Originally Posted by singdude
    Thank you, Heartshape for taking a time to answer my query.

    Could you shed some light about the manual ring which is used to focus the background or forground ? Does it have any play in controlling the depth of view ?

    I am very confused on this.

    Thank you.
    the manual ring is meant for focusing and not for adjustment of depth of field. Its like when you are slightly myopic. your eyes are capable of focusing on nearby things up to a certain short distance. They do this by changing the shape of you lens to change the focal length. But if you decide to focus of a further subject, you will tend to squint or make your eyes smaller which tend to make the image sharper. The image becomes sharper not because your eye lens was able to focus on the subject but because squinting makes a wider area of subject, near and far, come into focus. This is like adjusting the cameras aperture.

    Perhaps this might make things clearer for you. If you made 10 people stand in a straight line, from front to back, and you focused on person in the middle either with the manual focus ring (or depressing the shutter halfway - if you have an AF camera). If you set the aperture to the smallest number and took a picture, you will notice (if the people were spaced relatively far apart) that only the middle person is in focus. Now if you maintain the focus and just adjust the aperature to a smaller number and took the same photo, you will start to notice that even though you are focusing on just one person, more people in front and back become focused as well, as your aperture number increases. Try it and see.

    Take note that, you have to take the pictures to notice the difference, unless your camera comes with a depth of field preview function. This is because the camera always shows the smallest aperture number through the viewfinder to provide the brightest image for framing and focusing.

  6. #6
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    Default Re: Controlling the depth of view ...how ?

    Quote Originally Posted by singdude
    Thank you, Heartshape for taking a time to answer my query.

    Could you shed some light about the manual ring which is used to focus the background or forground ? Does it have any play in controlling the depth of view ?

    I am very confused on this.

    Thank you.
    the manual ring is meant for focusing and not for adjustment of depth of field. Its like when you are slightly myopic. your eyes are capable of focusing on nearby things up to a certain short distance. They do this by changing the shape of you lens to change the focal length. But if you decide to focus of a further subject, you will tend to squint or make your eyes smaller which tend to make the image sharper. The image becomes sharper not because your eye lens was able to focus on the subject but because squinting makes a wider area of subject, near and far, come into focus. This is like adjusting the cameras aperture.

    Perhaps this might make things clearer for you. If you made 10 people stand in a straight line, from front to back, and you focused on person in the middle either with the manual focus ring (or depressing the shutter halfway - if you have an AF camera). If you set the aperture to the smallest number and took a picture, you will notice (if the people were spaced relatively far apart) that only the middle person is in focus. Now if you maintain the focus and just adjust the aperature to a smaller number and took the same photo, you will start to notice that even though you are focusing on just one person, more people in front and back become focused as well, as your aperture number increases. Try it and see.

    Take note that, you have to take the pictures to notice the difference, unless your camera comes with a depth of field preview function. This is because the camera always shows the smallest aperture number through the viewfinder to provide the brightest image for framing and focusing.

  7. #7
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    Default Re: Controlling the depth of view ...how ?

    Hi, just to summarise what Heartshape & MDZ2 have said, Depth of Field is actually affected by a combination of 3 factors ...

    1) aperture size, which Heartshape has mentioned. Larger aperture, e.g. f/1.8, u will get shallower DOF, ie. blurrer background.

    2) focal length. In general, the greater the focal length or the closer u zoom, the shallower the DOF.

    3) working distance. The closer u are to the subject of focus, the shallower the DOF.

    The manual focus ring is used to focus the subject of the picture. DOF is affected by all 3 factors mentioned above.

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    Default Re: Controlling the depth of view ...how ?

    Quote Originally Posted by singdude
    Thank you, Heartshape for taking a time to answer my query.

    Could you shed some light about the manual ring which is used to focus the background or forground ? Does it have any play in controlling the depth of view ?

    I am very confused on this.

    Thank you.
    MDZ2 has answered your query on the focusing ring. Basically, the focusing ring is to help you focus on what you want when the camera focuses wrongly. You know, the camera's brain is not as advanced as ours and thus sometimes do not do what you want it to, so you have to do it yourself - focus manually.
    If you are not familiar with aperture and what it does for you where DOV (actually it's called Depth of Field, not View) is concerned, like MDZ2 said, line people or things from front to back and try shooting with different aperture settings (don forget to adjust the shutter speed to match accordingly). But sorry to contradict DMZ2, but you should focus on the font subject instead of the centre, because if you focus on the centre, what I said above about the 'third rule' will come into play and you will not really get a very clear picture of the different effects of different aperture settings. Certain aspects of photography are more chim than we would like. But we can use these to our advantage. See la, if we have a chance to meet at any outings, I'll try and explain it more to you.

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    Default Re: Controlling the depth of view ...how ?

    Thank you so much guys. It is like very clear to me now.

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    Default Re: Controlling the depth of view ...how ?

    heart shape, actually I said to focus on the middle person because depth of field does not just extend to the rear of the subject but also to the front, though to a smaller extent. But I chose the middle person so that it would be less to explain

  11. #11

    Default Re: Controlling the depth of view ...how ?

    DOF is also affected by the sensor size, and the circle of confusion.....

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