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Thread: A question on DOF of prosumers cam...

  1. #1

    Default A question on DOF of prosumers cam...

    I know prosumers cams cannot create the same DOF (Blurred) effect compared to DSLR... cos CCD is small.... juz wanna know whether the newer ones are able to?? sony 828, the minolta A1 or the panasonic Z10...

  2. #2

    Default you mean like this ?? not sure if its blurred enuff


    by dimage a1
    Last edited by solomon76; 12th November 2003 at 05:16 PM.

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    Not quite the out of focus look that u would expect from a relatively large aperture....... what was the f-stop? f/5.6?

  4. #4

    Default F=3.2

    F=3.2
    however at large zoom , there is a chance of blurring the background
    Last edited by solomon76; 12th November 2003 at 10:35 PM.

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    Quote Originally Posted by blurboiboi
    I know prosumers cams cannot create the same DOF (Blurred) effect compared to DSLR... cos CCD is small.... juz wanna know whether the newer ones are able to?? sony 828, the minolta A1 or the panasonic Z10...
    Nope. even newer ones like sony828 and minolta a1 CCD still smaller than DSLR.

    BUT you must try out whether it is acceptable to you.

  6. #6

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    I switched from my Canon A40 to the Nikon F80 purely for this reason; background blur.

    You simply cannot emulate the background blur in a film or digital SLR because of the shorter focal length.

    The above picture has a shallower DOF because it was taken at Max zoom and the subject was pretty near. If a film camera uses that amount of zoom, you will not be able to see the background almost.


    SLR users use the 85mmf1.4 wide open for portraits just to get that very shallow DOF. For prosumer digicams to achieve similar results you would probably need ard 1000mm(35mm equi.) of zoom just to get an actual 85mm focal length and perhaps even more since there arent any f1.4 digicams around.
    Last edited by marcwang; 12th November 2003 at 11:56 PM.

  7. #7

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    I know prosumers cams cannot create the same DOF (Blurred) effect compared to DSLR... cos CCD is small.... juz wanna know whether the newer ones are able to?? sony 828, the minolta A1 or the panasonic Z10...
    Hmmm, first time ever I've heard of that. Most prosumer digicams have a pre-set Portrait mode that ensures shallow Depth of Field (DOF). DOF is dependent on the f/ stop, and has nothing to do with the size of the CCD.

    Blurboiboi, maybe you can post a couple of pics to help us understand your confusion?


    I switched from my Canon A40 to the Nikon F80 purely for this reason; background blur.

    You simply cannot emulate the background blur in a film or digital SLR because of the shorter focal length.

    The above picture has a shallower DOF because it was taken at Max zoom and the subject was pretty near. If a film camera uses that amount of zoom, you will not be able to see the background almost.

    SLR users use the 85mmf1.4 wide open for portraits just to get that very shallow DOF. For prosumer digicams to achieve similar results you would probably need ard 1000mm(35mm equi.) of zoom just to get an actual 85mm focal length and perhaps even more since there arent any f1.4 digicams around.
    Marc, yes the A40 has a f/2.8-4.9 lens. (I'm not sure of the focal range.) But if you stuck the long end of the lens in your subject's face and shoot with the lens wide open at f/4.9, I'm sure the DOF will be shallow enough. No?

    Wow, going to film from digital eh?

    Hewland

  8. #8

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    F3.2 on dslr..


  9. #9

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    Quote Originally Posted by Hewland
    Hmmm, first time ever I've heard of that. Most prosumer digicams have a pre-set Portrait mode that ensures shallow Depth of Field (DOF). DOF is dependent on the f/ stop, and has nothing to do with the size of the CCD.

    Blurboiboi, maybe you can post a couple of pics to help us understand your confusion?

    Marc, yes the A40 has a f/2.8-4.9 lens. (I'm not sure of the focal range.) But if you stuck the long end of the lens in your subject's face and shoot with the lens wide open at f/4.9, I'm sure the DOF will be shallow enough. No?

    Wow, going to film from digital eh?

    Hewland
    I think the CCD does affect the DOF due to the mulitiplication factor involved. Cant really remember the exact explaination. Or maybe I am wrong too. But prosumer cam cant do that DOF mainly because of the small and short lens on them. Even with the protrait mode, you cant acheive the same effect on a SLR or DSLR.

    And erm, I really dun understand the latter part of your post. Confusing...

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    Quote Originally Posted by Hewland
    DOF is dependent on the f/ stop, and has nothing to do with the size of the CCD.
    erm Hewland, sorry to correct you but the size of the CCD does come into play for DOF. the aperture value of any camera is relative to the size of the "film" (in this case the CCD). aperture f/stop values measures light falling on the film and not DOF. so naturally the lens of a prosumer cam is able to get away with bigger f-stops (e.g. f/2.8, even f/2.0) naturally cos the amount of light needed to get to the small CCD is lesser. so... DoF of f/2.8 @ 100mm zoom on a prosumer cam is NOT as shallow as f/2.8 on a SLR mounted on a 100mm (equiv.) lens.

    hope that makes sense...
    Last edited by Larry; 13th November 2003 at 01:45 AM.

  11. #11

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    Quote Originally Posted by Hewland
    Hmmm, first time ever I've heard of that. Most prosumer digicams have a pre-set Portrait mode that ensures shallow Depth of Field (DOF). DOF is dependent on the f/ stop, and has nothing to do with the size of the CCD.
    Hi, depth of field is directly related to focal length and not just aperture.
    Digicams have a CCD that is much smaller than film/DSLRs, consequently there is a cropping factor of more than 4X involved which means that the focal length has >4 times lower than a SLR in order to get the same angle of view.

    The actual focal length of digicams is 7-30mm++. This translates to a really deep DOF. In fact a good approximation for an equivalent DOF from a SLR would be a f number >4 times that of the digicam.

    i.e f2 on a digicam has approximately the same DOF as f8 on an SLR.

    Try taking some shots with both and you will see the difference.

    blurboiboi: The direct answer to your question would be NO. Digicams will never equal SLRs in terms of DOF control as long as they are used under the SAME situations.

    However, you can achieve good background blur with digicams as long as you use them at macro distances.

  12. #12

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    End of the day, if you really want to have a good intended "blurred background" even on consumer/prosumer digital camera (spare the comparison with SLRs), you have to

    1) use the biggest aperture available or play around with the aperture value till you get enough depth of field yet the background is reasonably blurred.
    2) using the maximum zoom of your camera, position the subject as close as possible within your camera's focus distance limit and then use macro mode or manual focus to focus.
    3) ensure that the background is relatively far away from the subject.
    4) make sure you focus on your intended subject.

    of course consumer/prosumer digital camera doesn't have the kind of shallow DOF background effect of SLRs but the most important thing is that you have to learn how to maximise it's potential first.

    2 examples of shallow DOF background with my G3




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    Prosumer class digicams CAN produce pretty darn good background blur if that is what you really want have. You just need to master your camera. Caesium's toy shot is an excellent example. Those who went for AG12 will also recognise this pix, taken at very close range (3cm away).


    Even for portraits you can achieve pretty decent results, examplee below.


    Won't repeat what's already been posted. With a Coolpix 4500, there you have it.

  14. #14

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    Thanks to those who added to my post. I'll just stick to my understanding of DOF and how to achieve it.

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    Quote Originally Posted by Azure
    Prosumer class digicams CAN produce pretty darn good background blur if that is what you really want have. You just need to master your camera. Caesium's toy shot is an excellent example. Those who went for AG12 will also recognise this pix, taken at very close range (3cm away).


    Even for portraits you can achieve pretty decent results, examplee below.


    Won't repeat what's already been posted. With a Coolpix 4500, there you have it.

    You still cannot achieve the blur effect like that one posted by Junyang. No doubt the shots you posted have significant blur but you can still make out what is in the background. U have not really isolated the subject if that was the original intention (as I gather from the original poster). So for the potrait shot, the background bougainvilla is a distraction although not acutely so... in the case of the toy soldier shot, I guess that whatever is on the left of the pic (likely to be "trees" or some form of vegetation was deliberately left in view such that it can be identified as such.... but to achieve the highly defocussed background of Junyang's cute cat shot, I think it's a physical impossibility on prosumer digicams with CCDs the size they are now...

  16. #16

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    Azure, both your examples are hardly considered good examples of background blur in any case.

    There's no way a digicam can achieve good blur except for macros as I've previously mentioned. The key thing would be to be more selective about your backgrounds as there is no way to completely isolate it with a digicam.

    The only good bokeh comes when you are taking insect portraits like this(s602):

    For anything more than 50cm away, you won't get a decent blur no matter how hard you try. Hence, dogs, humans and anything larger need not apply.

    Best is to choose your backgrounds properly.

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    Quote Originally Posted by Zerstorer
    Azure, both your examples are hardly considered good examples of background blur in any case.

    There's no way a digicam can achieve good blur except for macros as I've previously mentioned. The key thing would be to be more selective about your backgrounds as there is no way to completely isolate it with a digicam.

    The only good bokeh comes when you are taking insect portraits like this(s602):

    For anything more than 50cm away, you won't get a decent blur no matter how hard you try. Hence, dogs, humans and anything larger need not apply.

    Best is to choose your backgrounds properly.

    Care to explain the insect can humans and dogs cannot rule of thumb? In English hor...... thanks!

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    the subject (humans, dogs, etc) would fill the frame and the distance between the nearest and furthest part of the subject is not sufficient to have good "blurring".

  19. #19

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    Camera-to-Subject:Subject-to-Background

    Distance ratio. Make sure the first number is many many times smaller than the other.

    A large subject will require a greater working distance to fit in the frame. This makes the first number more significant and hence greatly reduces the possibility of blur as the 2nd number will have to be greatly increased which is not always possible.

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    Quote Originally Posted by Zerstorer
    Camera-to-Subject:Subject-to-Background

    Distance ratio. Make sure the first number is many many times smaller than the other.

    A large subject will require a greater working distance to fit in the frame. This makes the first number more significant and hence greatly reduces the possibility of blur as the 2nd number will have to be greatly increased which is not always possible.

    OOooo...... so simple!! I see...... wow!! I never saw it that way.......

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