35mm SLR lenses on digital

Discussion in 'Digital Photography' started by Oscar, Apr 18, 2007.

  1. Oscar

    Oscar Guest

    Hi,

    I've owned a Nikon F401s for many years and always enjoyed using it,
    but with the onset of digital cameras my SLR was assigned to the
    cupboard in favour of a couple of super zoom digital cameras. Anyway
    I now feel the need to change away from these back to a proper SLR and
    have been looking at the Nikon D40, D40x and D80.

    I already own three lenses form my SLR days and I know if I brought
    either of the D40 models these lenses will not auto focus.

    What I don't understand is the way the lenses are now described

    ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
    film days, understand.

    All new lenses now seem to be marketed this way, but what if you
    already have lenses which are from the 35mm film days. Does it mean
    the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
    or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
    1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
    somebody please help.

    Please don't turn this message in to a debate over which camera is the
    best as there are loads of these around, I know the pitfalls of the
    D40 models over the D80.

    Thanks

    Oscar
     
    Oscar, Apr 18, 2007
    #1
    1. Advertising

  2. On 18 Apr 2007 07:59:14 -0700, Oscar <> wrote:
    > Hi,
    >
    > I've owned a Nikon F401s for many years and always enjoyed using it,
    > but with the onset of digital cameras my SLR was assigned to the
    > cupboard in favour of a couple of super zoom digital cameras. Anyway
    > I now feel the need to change away from these back to a proper SLR and
    > have been looking at the Nikon D40, D40x and D80.
    >
    > I already own three lenses form my SLR days and I know if I brought
    > either of the D40 models these lenses will not auto focus.
    >
    > What I don't understand is the way the lenses are now described
    >
    > ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
    > film days, understand.
    >
    > All new lenses now seem to be marketed this way, but what if you
    > already have lenses which are from the 35mm film days. Does it mean
    > the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
    > or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
    > 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
    > somebody please help.


    Multiplied by 1.5, so 52.5-105mm.

    -dms
     
    Daniel Silevitch, Apr 18, 2007
    #2
    1. Advertising

  3. Oscar

    Bob Williams Guest

    Oscar wrote:
    > Hi,
    >
    > I've owned a Nikon F401s for many years and always enjoyed using it,
    > but with the onset of digital cameras my SLR was assigned to the
    > cupboard in favour of a couple of super zoom digital cameras. Anyway
    > I now feel the need to change away from these back to a proper SLR and
    > have been looking at the Nikon D40, D40x and D80.
    >
    > I already own three lenses form my SLR days and I know if I brought
    > either of the D40 models these lenses will not auto focus.
    >
    > What I don't understand is the way the lenses are now described
    >
    > ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
    > film days, understand.
    >
    > All new lenses now seem to be marketed this way, but what if you
    > already have lenses which are from the 35mm film days. Does it mean
    > the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
    > or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
    > 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
    > somebody please help.
    >
    > Please don't turn this message in to a debate over which camera is the
    > best as there are loads of these around, I know the pitfalls of the
    > D40 models over the D80.
    >
    > Thanks
    >
    > Oscar
    >

    Your old Nikon Lenses on a new Nikon D40 etc, will act as if the focal
    length is (Old F.L. X Magnification Factor). The M.F. for the D40 is
    1.5, so your old 35-70will behave like a 52.5-105 on the D40
    Bob Williams
     
    Bob Williams, Apr 18, 2007
    #3
  4. Oscar wrote:
    > What I don't understand is the way the lenses are now described
    >
    > ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
    > film days, understand.
    >
    > All new lenses now seem to be marketed this way, but what if you
    > already have lenses which are from the 35mm film days. Does it mean
    > the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
    > or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
    > 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
    > somebody please help.


    For me the easiest way is to remember that what is stamped on the barrel is
    standardized for 35mm film. That means, if you are using that D80 kit lens
    (18-70mm) on a 35mm film camera than you will get an 18-70mm zoom lens.

    Now, compared to 35mm film the D80 has a conversion factor of 1.5. That
    means that because of the smaller sensor compared to film this lens when
    used on a D80 has a zoom range of 18x1.5-70x1.5 which equals 27-105mm.
    Same with your old lenses. 35-70 on 35mm film times 1.5 on the D80 equals
    52-105mm.

    Unfortunately this conversion is necessary because different cameras have
    different sensors dimensions and therefore different conversion factors,
    e.g. if you were to use this D80 kit lens on some other camera you probably
    end up with slightly different numbers. The one thing to remember is that
    what is stamped on the lens is always for 35mm film.

    jue
     
    Jürgen Exner, Apr 18, 2007
    #4
  5. In article <JDqVh.5522$F32.1633@trndny02>, Jürgen Exner
    <> wrote:

    > Unfortunately this conversion is necessary because different cameras have
    > different sensors dimensions and therefore different conversion factors,
    > e.g. if you were to use this D80 kit lens on some other camera you probably
    > end up with slightly different numbers. The one thing to remember is that
    > what is stamped on the lens is always for 35mm film.


    Or, more accurately, what is stamped on the lens is always WHAT THE
    FOCAL LENGTH ACTUALLY IS.

    The field of view that focal length gives (compared to 35 mm) is what
    the magnification factor tells you. As in, your 50 mm lens will give
    the field of view which habit makes you expect from a 75 mm. But the
    focal length, which is an inherent characteristic of the lens. doesn't
    change.
     
    Scott Schuckert, Apr 18, 2007
    #5
  6. Oscar

    King Sardon Guest

    On Wed, 18 Apr 2007 15:16:57 GMT, "Jürgen Exner"
    <> wrote:

    >Oscar wrote:
    >> What I don't understand is the way the lenses are now described
    >>
    >> ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
    >> film days, understand.
    >>
    >> All new lenses now seem to be marketed this way, but what if you
    >> already have lenses which are from the 35mm film days. Does it mean
    >> the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
    >> or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
    >> 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
    >> somebody please help.

    >
    >For me the easiest way is to remember that what is stamped on the barrel is
    >standardized for 35mm film. That means, if you are using that D80 kit lens
    >(18-70mm) on a 35mm film camera than you will get an 18-70mm zoom lens.
    >
    >Now, compared to 35mm film the D80 has a conversion factor of 1.5. That
    >means that because of the smaller sensor compared to film this lens when
    >used on a D80 has a zoom range of 18x1.5-70x1.5 which equals 27-105mm.
    >Same with your old lenses. 35-70 on 35mm film times 1.5 on the D80 equals
    >52-105mm.
    >
    >Unfortunately this conversion is necessary because different cameras have
    >different sensors dimensions and therefore different conversion factors,
    >e.g. if you were to use this D80 kit lens on some other camera you probably
    >end up with slightly different numbers. The one thing to remember is that
    >what is stamped on the lens is always for 35mm film.


    Focal length is a property of the lens and does not change, no matter
    what system you mount it on. But because the image circle is cropped
    more in small sensor systems, the FIELD OF VIEW changes, AS THOUGH the
    focal length changed, compared to 35mm.

    What is stamped on the lens is a property of the lens and does not
    change.

    It's like taking a medium format lens (for instance a Hasselblad 80mm
    lens) and putting it on a 35mm camera. On the 35mm, it behaves like an
    80mm lens! But its field of view is different than when it was on the
    'Blad.

    KS
     
    King Sardon, Apr 18, 2007
    #6
  7. Oscar

    C J Campbell Guest

    On 2007-04-18 07:59:14 -0700, Oscar <> said:

    > Hi,
    >
    > I've owned a Nikon F401s for many years and always enjoyed using it,
    > but with the onset of digital cameras my SLR was assigned to the
    > cupboard in favour of a couple of super zoom digital cameras. Anyway
    > I now feel the need to change away from these back to a proper SLR and
    > have been looking at the Nikon D40, D40x and D80.
    >
    > I already own three lenses form my SLR days and I know if I brought
    > either of the D40 models these lenses will not auto focus.
    >
    > What I don't understand is the way the lenses are now described
    >
    > ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
    > film days, understand.
    >
    > All new lenses now seem to be marketed this way, but what if you
    > already have lenses which are from the 35mm film days. Does it mean
    > the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
    > or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
    > 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
    > somebody please help.
    >
    > Please don't turn this message in to a debate over which camera is the
    > best as there are loads of these around, I know the pitfalls of the
    > D40 models over the D80.
    >
    > Thanks
    >
    > Oscar


    An 35-70mm lens is a 35-70mm lens, no matter what camera it is on.

    What they are saying is that since the sensor in a digital camera is
    smaller than a frame of 35mm film, then the part of the image circle
    that actually gets recorded is smaller. It is like taking a 35mm slide
    and just keeping the middle part of it.

    The multiplier is appoximately 1.5, which makes it easy. 28mm now
    records the same size image as a 42mm lens did. It isn't any sharper;
    it is just as if you cropped the middle out of all your 35mm pictures.

    Your old lenses will work just as they always did, only now your wide
    angle lenses will not seem as wide as they once were, and your
    telephoto lenses will seem more powerful. They aren't, but you just
    don't get to see the entire image they are capable of producing.

    This has its good and bad points. The bad is that you are now forced to
    use an APS size film format, complete with all of its limitations in
    resolution. The good is that the center part of the image on your old
    lenses was the sharpest part anyway. So you have lost the fuzzy edges,
    the vignetting, and all the other problems you remember from film days.
    The manufacturers don't want you to miss out on those, though, so Nikon
    makes "DX" lenses that bring back the vignetting, if not the less sharp
    edges. I say you don't need 'em. Use your old lenses.
    --
    Waddling Eagle
    World Famous Flight Instructor
     
    C J Campbell, Apr 18, 2007
    #7
  8. Oscar

    Guest

    On Apr 18, 7:59 am, Oscar <> wrote:
    > Hi,
    >
    > I've owned a Nikon F401s for many years and always enjoyed using it,
    > but with the onset of digital cameras my SLR was assigned to the
    > cupboard in favour of a couple of super zoom digital cameras. Anyway
    > I now feel the need to change away from these back to a proper SLR and
    > have been looking at the Nikon D40, D40x and D80.
    >
    > I already own three lenses form my SLR days and I know if I brought
    > either of the D40 models these lenses will not auto focus.
    >
    > What I don't understand is the way the lenses are now described
    >
    > ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
    > film days, understand.
    >
    > All new lenses now seem to be marketed this way, but what if you
    > already have lenses which are from the 35mm film days. Does it mean
    > the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
    > or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
    > 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
    > somebody please help.
    >
    > Please don't turn this message in to a debate over which camera is the
    > best as there are loads of these around, I know the pitfalls of the
    > D40 models over the D80.
    >
    > Thanks
    >
    > Oscar


    The way I remember this is to imagine the size of the sensor against
    the size of the film frame. As the sensor is only 2/3 the size of the
    35mm film frame, it only "sees" the center 2/3 of the image that is
    thrown onto the "backplane" of the camera. i.e. Imagine that the outer
    1/3 of the image falls beyond the outside edges of the digital sensor.
    So the effect is the same as if you had zoomed in on the center 2/3 of
    a 35mm film frame. (much like "digital zoom" works on P&S digital
    cameras). So the effect is the same as if you had zoomed 1.5 times
    with a 35mm camera.

    HTH.

    /M
     
    , Apr 18, 2007
    #8
  9. "Oscar" <> wrote in message
    news:...
    > Hi,
    >
    > I've owned a Nikon F401s for many years and always enjoyed using it,
    > but with the onset of digital cameras my SLR was assigned to the
    > cupboard in favour of a couple of super zoom digital cameras. Anyway
    > I now feel the need to change away from these back to a proper SLR and
    > have been looking at the Nikon D40, D40x and D80.
    >
    > I already own three lenses form my SLR days and I know if I brought
    > either of the D40 models these lenses will not auto focus.
    >
    > What I don't understand is the way the lenses are now described
    >
    > ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
    > film days, understand.
    >
    > All new lenses now seem to be marketed this way, but what if you
    > already have lenses which are from the 35mm film days. Does it mean
    > the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
    > or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
    > 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
    > somebody please help.


    The 1.5 is a multiplier. Some have objected to the term "multiplier" on the
    grounds that the actual focal length is not changed; your lens is still
    35-70mm as it always was. Nevertheless, the 1.5x lens factor does mean that
    in most respects your 35-70 becomes *equivalent* to a 52.5-105mm lens on a
    35. The only reason it's commonly expressed this way is that most of us are
    familiar with focal lengths on a 35mm camera. It is useful to have some
    standard for visualizing the effects of different focal lengths on angle of
    view, and 35mm is that standard because it's been around so long.


    >
    > Please don't turn this message in to a debate over which camera is the
    > best as there are loads of these around, I know the pitfalls of the
    > D40 models over the D80.


    Not much to debate anyway, since you already know about the autofocus issues
    with older lenses on the D40 models.. The D40, D40x and D80 are all top
    choices in their respective classes.

    Neil
     
    Neil Harrington, Apr 18, 2007
    #9
  10. Oscar

    Jim Guest

    "Oscar" <> wrote in message
    news:...
    > Hi,
    >
    > I've owned a Nikon F401s for many years and always enjoyed using it,
    > but with the onset of digital cameras my SLR was assigned to the
    > cupboard in favour of a couple of super zoom digital cameras. Anyway
    > I now feel the need to change away from these back to a proper SLR and
    > have been looking at the Nikon D40, D40x and D80.
    >
    > I already own three lenses form my SLR days and I know if I brought
    > either of the D40 models these lenses will not auto focus.
    >
    > What I don't understand is the way the lenses are now described
    >
    > ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
    > film days, understand.
    >
    > All new lenses now seem to be marketed this way, but what if you
    > already have lenses which are from the 35mm film days. Does it mean
    > the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
    > or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
    > 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
    > somebody please help.
    >
    > Please don't turn this message in to a debate over which camera is the
    > best as there are loads of these around, I know the pitfalls of the
    > D40 models over the D80.
    >
    > Thanks
    >
    > Oscar
    >

    It is the angle of view that changes. So, a 105mm lens on my D70 has the
    same angle of view as a 150mm lens on my F3.
    Jim
     
    Jim, Apr 18, 2007
    #10
  11. Oscar <> writes:
    > What I don't understand is the way the lenses are now described ie
    > the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
    > film days, understand.
    >
    > All new lenses now seem to be marketed this way, but what if you
    > already have lenses which are from the 35mm film days. Does it mean
    > the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
    > or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
    > 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
    > somebody please help.


    http://hannemyr.com/photo/crop.html

    --
    - gisle hannemyr [ gisle{at}hannemyr.no - http://hannemyr.com/photo/ ]
    ------------------------------------------------------------------------
    Sigma SD10, Kodak DCS460, Canon Powershot G5, Olympus 2020Z
    ------------------------------------------------------------------------
     
    Gisle Hannemyr, Apr 20, 2007
    #11
  12. Oscar

    cmyk Guest

    Hi Oscar,

    The cropping/magnification issues have been well enough dealth with, but the other thing you might need to think about is the effect
    on DoF.

    Since you'll be enlarging from a smaller 'film', a print of a given size will have greater DoF. As an example, to get the same DoF
    from a 50mm lens on the DSLR (which gives the same FoV as a 75mm lens on a FSLR) you'll need to open the aperture up by two stops.

    Cheers
    --
    cmyk
    "Oscar" <> wrote in message news:...
    > Hi,
    >
    > I've owned a Nikon F401s for many years and always enjoyed using it,
    > but with the onset of digital cameras my SLR was assigned to the
    > cupboard in favour of a couple of super zoom digital cameras. Anyway
    > I now feel the need to change away from these back to a proper SLR and
    > have been looking at the Nikon D40, D40x and D80.
    >
    > I already own three lenses form my SLR days and I know if I brought
    > either of the D40 models these lenses will not auto focus.
    >
    > What I don't understand is the way the lenses are now described
    >
    > ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
    > film days, understand.
    >
    > All new lenses now seem to be marketed this way, but what if you
    > already have lenses which are from the 35mm film days. Does it mean
    > the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
    > or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
    > 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
    > somebody please help.
    >
    > Please don't turn this message in to a debate over which camera is the
    > best as there are loads of these around, I know the pitfalls of the
    > D40 models over the D80.
    >
    > Thanks
    >
    > Oscar
    >
     
    cmyk, Apr 20, 2007
    #12
  13. Oscar

    dj_nme Guest

    cmyk wrote:
    > Hi Oscar,
    >
    > The cropping/magnification issues have been well enough dealth with, but
    > the other thing you might need to think about is the effect on DoF.
    >
    > Since you'll be enlarging from a smaller 'film', a print of a given size
    > will have greater DoF.


    Only if using a "35mm equivalent" focal length on a crop-format DSLR
    camera, eg: a 3.5cm lens on a DSLR to get the same angle of view as a
    5cm lens on a 35mm film SLR (or FF DSLR) camera.
    This is a function of the actual focal length used to achieve the same
    angle of view.

    > As an example, to get the same DoF from a 50mm
    > lens on the DSLR (which gives the same FoV as a 75mm lens on a FSLR)
    > you'll need to open the aperture up by two stops.


    It would show greater DoF than a 75mm lens on a FF sensor (or 35mm film)
    DSLR camera, but less DoF than if the same 50m (5cm) lens when it's used
    on a FF DSLR (or film) camera.
    This is also a function of the actual focal length used to achieve the
    same angle of view.

    If you tested by printing both at the same size, you would discover that
    the 1.5x crop DSLR has 2/3 (two thirds) the DoF of the same lens used on
    a FF DSLR (or 35mm film) camera, if images are taken with the actual
    same lens on both a 1.5x crop DSLR and a FF DSLR (or 35mm film) camera.
    This is caused by the 30% extra enlargement required from the 1.5x crop
    sensor image to be printed at the same size as an image from a FF sensor
    camera.
     
    dj_nme, Apr 20, 2007
    #13
  14. Oscar

    cmyk Guest

    If you read the OP's posts you'll see he's talking about a Nikon DSLR. Nikon doesn't make full frame sensors. My comments were for
    the DSLRs Nikon does make, not some hypothetical camera they don't. Nikon's DSLRs all have a 1.5 FoV crop factor. Do the math and
    you'll find I got it right.

    --
    cmyk


    "dj_nme" <> wrote in message news:4628d06f$0$25447$...
    > cmyk wrote:
    >> Hi Oscar,
    >>
    >> The cropping/magnification issues have been well enough dealth with, but the other thing you might need to think about is the
    >> effect on DoF.
    >>
    >> Since you'll be enlarging from a smaller 'film', a print of a given size will have greater DoF.

    >
    > Only if using a "35mm equivalent" focal length on a crop-format DSLR camera, eg: a 3.5cm lens on a DSLR to get the same angle of
    > view as a 5cm lens on a 35mm film SLR (or FF DSLR) camera.
    > This is a function of the actual focal length used to achieve the same angle of view.
    >
    >> As an example, to get the same DoF from a 50mm lens on the DSLR (which gives the same FoV as a 75mm lens on a FSLR) you'll need
    >> to open the aperture up by two stops.

    >
    > It would show greater DoF than a 75mm lens on a FF sensor (or 35mm film) DSLR camera, but less DoF than if the same 50m (5cm) lens
    > when it's used on a FF DSLR (or film) camera.
    > This is also a function of the actual focal length used to achieve the same angle of view.
    >
    > If you tested by printing both at the same size, you would discover that the 1.5x crop DSLR has 2/3 (two thirds) the DoF of the
    > same lens used on a FF DSLR (or 35mm film) camera, if images are taken with the actual same lens on both a 1.5x crop DSLR and a FF
    > DSLR (or 35mm film) camera.
    > This is caused by the 30% extra enlargement required from the 1.5x crop sensor image to be printed at the same size as an image
    > from a FF sensor camera.
     
    cmyk, Apr 20, 2007
    #14
  15. Oscar

    dj_nme Guest

    cmyk wrote:
    > If you read the OP's posts you'll see he's talking about a Nikon DSLR.
    > Nikon doesn't make full frame sensors. My comments were for the DSLRs
    > Nikon does make, not some hypothetical camera they don't. Nikon's DSLRs
    > all have a 1.5 FoV crop factor. Do the math and you'll find I got it right.
    >


    Do the experiment and you will find that I'm correct.
    Using a shorter lens to make up for the crop factor means that you will
    have more DoF.
    Using the same lens (ie: the same 50mm lens on both your film and your
    Digital Nikon SLR camera) as on a 35mm film Nikon will result in images
    with 2/3 (two thirds) the DoF, due to the extra enlargement required to
    print at the same size.
    It is the exactly the same as using a 80mm lens on a 6x6 120 film camera
    compared to an 80mm lens (or the same medium format lens with an
    adaptor) on a 35mm film camera, the prints made from the 6x6 negs will
    have more aparrent DoF than the prints made from the 35mm negs.
    If you could go the other way (and somehow fit a 35mm lens on a medium
    format body, also making it cover the full 6x6 frame), then you'd find
    the same thing and the MF prints will seem to have more DoF due to less
    enlargement for the same print size.
     
    dj_nme, Apr 21, 2007
    #15
  16. Oscar

    cmyk Guest

    Maybe you should just go out and take a photo or two. Quite obviously, the math is beyond you.

    --
    cmyk
    "dj_nme" <> wrote in message news:462956a9$0$25464$...
    > cmyk wrote:
    >> If you read the OP's posts you'll see he's talking about a Nikon DSLR.
    >> Nikon doesn't make full frame sensors. My comments were for the DSLRs
    >> Nikon does make, not some hypothetical camera they don't. Nikon's DSLRs
    >> all have a 1.5 FoV crop factor. Do the math and you'll find I got it right.
    >>

    >
    > Do the experiment and you will find that I'm correct.
    > Using a shorter lens to make up for the crop factor means that you will
    > have more DoF.
    > Using the same lens (ie: the same 50mm lens on both your film and your
    > Digital Nikon SLR camera) as on a 35mm film Nikon will result in images
    > with 2/3 (two thirds) the DoF, due to the extra enlargement required to
    > print at the same size.
    > It is the exactly the same as using a 80mm lens on a 6x6 120 film camera
    > compared to an 80mm lens (or the same medium format lens with an
    > adaptor) on a 35mm film camera, the prints made from the 6x6 negs will
    > have more aparrent DoF than the prints made from the 35mm negs.
    > If you could go the other way (and somehow fit a 35mm lens on a medium
    > format body, also making it cover the full 6x6 frame), then you'd find
    > the same thing and the MF prints will seem to have more DoF due to less
    > enlargement for the same print size.
     
    cmyk, Apr 21, 2007
    #16
  17. Oscar

    cmyk Guest

    For anyone interested in why you'd need a wider aperture on the DSLR than on a 35mm FSLR:

    Nikon DSLR-
    Sensor Format: 24*16mm
    Focal Length: 50mm
    Aperture: f4
    Subject Distance: 4.05m
    FoV: 1.92m*1.28m
    Print: 6"x4"
    Viewing Distance: 14"
    Required angular resolution: 1.333 arcminute
    CoC: 21.7 microns
    DoF: 58.3"


    Any 35mm film or full-frame DSLR camera-
    Film Format: 36*24mm
    Focal Length: 75mm
    Aperture: f4
    Subject Distance: 4.075m
    FoV: 1.92m*1.28m
    Print: 6"x4"
    Viewing Distance: 14"
    Required angular resolution: 1.333 arcminute
    CoC: 32.6 microns
    DoF: 30.0"

    Any 35mm film or full-frame DSLR camera-
    Film Format: 36*24mm
    Focal Length: 75mm
    Aperture: f7.5
    Subject Distance: 4.075m
    FoV: 1.92m*1.28m
    Print: 6"x4"
    Viewing Distance: 14"
    Required angular resolution: 1.333 arcminute
    CoC: 32.6 microns
    DoF: 57.9"

    So, for the same scene, the Nikon DSLR will render it with the same DoF as a 35mm film or full-frame DSLR camera when the aperture
    is opened up 1 5/6 stops (ie about 2 stops).

    Cheers
    --
    cmyk



    "cmyk" <> wrote in message news:...
    > Hi Oscar,
    >
    > The cropping/magnification issues have been well enough dealth with, but the other thing you might need to think about is the
    > effect on DoF.
    >
    > Since you'll be enlarging from a smaller 'film', a print of a given size will have greater DoF. As an example, to get the same DoF
    > from a 50mm lens on the DSLR (which gives the same FoV as a 75mm lens on a FSLR) you'll need to open the aperture up by two stops.
    >
    > Cheers
    > --
    > cmyk
    > "Oscar" <> wrote in message news:...
    >> Hi,
    >>
    >> I've owned a Nikon F401s for many years and always enjoyed using it,
    >> but with the onset of digital cameras my SLR was assigned to the
    >> cupboard in favour of a couple of super zoom digital cameras. Anyway
    >> I now feel the need to change away from these back to a proper SLR and
    >> have been looking at the Nikon D40, D40x and D80.
    >>
    >> I already own three lenses form my SLR days and I know if I brought
    >> either of the D40 models these lenses will not auto focus.
    >>
    >> What I don't understand is the way the lenses are now described
    >>
    >> ie the kit lenses on the D80 is 18-70mm which equals 27-105mm in 35mm
    >> film days, understand.
    >>
    >> All new lenses now seem to be marketed this way, but what if you
    >> already have lenses which are from the 35mm film days. Does it mean
    >> the lens will be as it says on the barrel ie 35-70mm will be 35-70mm
    >> or will it be multiplied 1.5 so will be 52.5-105mm or do you divide by
    >> 1.5 so it becomes 23.3-46.6mm. This is the bit I'm unsure of can
    >> somebody please help.
    >>
    >> Please don't turn this message in to a debate over which camera is the
    >> best as there are loads of these around, I know the pitfalls of the
    >> D40 models over the D80.
    >>
    >> Thanks
    >>
    >> Oscar
    >>

    >
     
    cmyk, Apr 21, 2007
    #17
  18. Oscar

    dj_nme Guest

    cmyk wrote (and fucked up by putting the previous message replies below
    his sig delimiter):

    >"dj_nme" <> wrote in message

    news:462956a9$0$25464$...
    >
    >> cmyk wrote:
    >>
    >>> If you read the OP's posts you'll see he's talking about a Nikon

    >DSLR. Nikon doesn't make full frame sensors. My comments were for the
    >DSLRs Nikon does make, not some hypothetical camera they don't.

    Nikon's >DSLRs all have a 1.5 FoV crop factor. Do the math and you'll
    find I got >it right.
    >>>

    >>
    >> Do the experiment and you will find that I'm correct.
    >> Using a shorter lens to make up for the crop factor means that you

    will have more DoF.
    >> Using the same lens (ie: the same 50mm lens on both your film and

    your Digital Nikon SLR camera) as on a 35mm film Nikon will result in
    images with 2/3 (two thirds) the DoF, due to the extra enlargement
    required to print at the same size.
    >> It is the exactly the same as using a 80mm lens on a 6x6 120 film

    camera compared to an 80mm lens (or the same medium format lens with an
    adaptor) on a 35mm film camera, the prints made from the 6x6 negs will
    have more aparrent DoF than the prints made from the 35mm negs.
    >> If you could go the other way (and somehow fit a 35mm lens on a

    medium format body, also making it cover the full 6x6 frame), then you'd
    find the same thing and the MF prints will seem to have more DoF due to
    less enlargement for the same print size.
    >
    > Maybe you should just go out and take a photo or two. Quite obviously,
    > the math is beyond you.


    You must be pretty dim if you can't take the evidence of you eyes.
    Thay is how I can to the conclusion that using the same lens on a film
    SLR compared to a DSLR results in different DoF for the same print size.
    I have done the experiment with film and a 35mm SLR and a 6x6 SLR using
    the same lens.
    I have also done the same the same thing with a 35mm film SLR versus a DSLR.
    Using a lens on a smaller format results in shallower DoF when both
    images are printed full page on the same sized paper, this is due to
    greater enlargment required to make the smaller format image fill the page.
    DoF in the printed image is determined by the size of the circles of
    confusion, the bigger the print for a given neg (or sensor size for
    digital) the bigger the circles appear and the shallower the DoF in the
    print is.
    No amount of sillines on your part will change this fact.

    --
    This is where your signature (sig) goes,
    not the previous messages in the thread.
     
    dj_nme, Apr 21, 2007
    #18
  19. Oscar

    dj_nme Guest

    cmyk wrote:

    > For anyone interested in why you'd need a wider aperture on the DSLR
    > than on a 35mm FSLR:
    >
    > Nikon DSLR-
    > Sensor Format: 24*16mm
    > Focal Length: 50mm
    > Aperture: f4
    > Subject Distance: 4.05m
    > FoV: 1.92m*1.28m
    > Print: 6"x4"
    > Viewing Distance: 14"
    > Required angular resolution: 1.333 arcminute
    > CoC: 21.7 microns
    > DoF: 58.3"
    >
    >
    > Any 35mm film or full-frame DSLR camera-
    > Film Format: 36*24mm
    > Focal Length: 75mm
    > Aperture: f4
    > Subject Distance: 4.075m
    > FoV: 1.92m*1.28m
    > Print: 6"x4"
    > Viewing Distance: 14"
    > Required angular resolution: 1.333 arcminute
    > CoC: 32.6 microns
    > DoF: 30.0"
    >
    > Any 35mm film or full-frame DSLR camera-
    > Film Format: 36*24mm
    > Focal Length: 75mm
    > Aperture: f7.5
    > Subject Distance: 4.075m
    > FoV: 1.92m*1.28m
    > Print: 6"x4"
    > Viewing Distance: 14"
    > Required angular resolution: 1.333 arcminute
    > CoC: 32.6 microns
    > DoF: 57.9"
    >
    > So, for the same scene, the Nikon DSLR will render it with the same DoF
    > as a 35mm film or full-frame DSLR camera when the aperture is opened up
    > 1 5/6 stops (ie about 2 stops).
    >
    > Cheers


    This does NOT contradict what I have written, it has actualy confirmed
    part of what I wrote.
    If you preserve he FoV by using a shorter lens on a smaller format (1.5x
    crop DSLR Vs 35mm full frame) you have greater DoF for the same aperture.
    If you use the same focal length on a 1.5x crop DSLR (and a narrower VoF
    than on a 35mm film SLR), then the DoF will be reduced.
    This is all assuming that the all the images are printed to the same
    size for comparison.
    The bigger the print, more of the image apears to be out of focus, as
    the slight bluring that isn't aparrent in parts of the image that are
    normaly covered by DoF in the smaller sized print are made more obvious
    the bigger it is printed.

    --
    sig goes here, not the previous reply.
     
    dj_nme, Apr 21, 2007
    #19
  20. Oscar

    Robert Coe Guest

    On Wed, 18 Apr 2007 11:56:22 -0400, Scott Schuckert <> wrote:
    : In article <JDqVh.5522$F32.1633@trndny02>, Jürgen Exner
    : <> wrote:
    :
    : > Unfortunately this conversion is necessary because different cameras have
    : > different sensors dimensions and therefore different conversion factors,
    : > e.g. if you were to use this D80 kit lens on some other camera you probably
    : > end up with slightly different numbers. The one thing to remember is that
    : > what is stamped on the lens is always for 35mm film.
    :
    : Or, more accurately, what is stamped on the lens is always WHAT THE
    : FOCAL LENGTH ACTUALLY IS.
    :
    : The field of view that focal length gives (compared to 35 mm) is what
    : the magnification factor tells you. As in, your 50 mm lens will give
    : the field of view which habit makes you expect from a 75 mm. But the
    : focal length, which is an inherent characteristic of the lens. doesn't
    : change.

    Which means, IMO, that it's easier to ignore the conversion factor and force
    yourself to re-learn what focal lengths constitute "wide angle", "normal", and
    "telephoto" for your camera. It takes a bit of getting used to, but it spares
    you from having to do the conversion every time you pick up a new lens.

    This problem isn't new, BTW. In the old days most serious photographers had at
    least a 120 roll film camera as well as a 35mm, and lenses of the same focal
    length behaved very differently in those two formats. (No, lenses weren't
    interchangeable between the two formats, but that's beside the point. Not all
    lenses are interchangeable between digital and 35mm film cameras either.)

    Bob
     
    Robert Coe, Apr 21, 2007
    #20
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