Nikon D50 + 105mm 2.8 micro

Discussion in 'Digital Photography' started by NikV, Oct 3, 2005.

  1. NikV

    NikV Guest

    This lens gives 1:1 on 35mm film cameras, will it give a greater than 1:1 on
    a reduced size sensor like the D50
     
    NikV, Oct 3, 2005
    #1
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  2. NikV

    John Bean Guest

    1:1 means just that - the image on the film/sensor is
    lifesize. The size of the sensor film is not the issue until
    you enlarge it.
     
    John Bean, Oct 3, 2005
    #2
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  3. NikV

    NikV Guest

    doh - of course - need to engage brain before typing :))

    nik
     
    NikV, Oct 3, 2005
    #3
  4. Hi Nik,

    I think the D70 has a similar sized sensor to the D50 and the Nikon
    105 mm macro lens gives a greater degree of magnification when used on
    the D70 than it does when used on my F100.

    At closest focus on the D70, the frame captures about 70 mm wide.

    You can check for yourself by going to this link;

    http://freespace.virgin.net/george.gdingwall/pages/test.html

    I have an image there taken with the D70 and the 105 mm macro lens at
    closest focus. You can clearly see that the image is greater than 1:1.
    The image on the site is a full frame un-cropped image.

    Hope this helps.

    Bye for now,

    George Dingwall

    Invergordon, Scotland

    http://freespace.virgin.net/george.gdingwall/index.html
     
    George Dingwall, Oct 3, 2005
    #4
  5. I don't think that this can be right. The D70 image sensor is 23.7 mm
    wide. So at 1:1 imaging you should only have about 24 mm filling your
    image horizontally. I don't think you are at maximum magnification. Are
    you sure your focus limit switch is set to the full focus range?

    To address the original question: I believe that 35 mm film has a
    horizontal dimension of 36 mm. At 1:1 imaging of, say, a ruler, the
    image should therefore contain 36 mm marks. With the D70, also at 1:1
    imaging, the full image will show 23 mm marks. If the image from both
    cameras is displayed the same size on a monitor or printed to the same
    size on paper, the D70 will appear to have higher magnification. But on
    the sensor, the magnification is 1:1 in both cases.
     
    john_doe_ph_d, Oct 3, 2005
    #5
  6. NikV

    NikV Guest

    now I'm puzzled if the sensor was 35mm wide (I know its not) then surely at
    1:1 the object (ruler in this case) should also be 35mm(smaller for a
    smaller sensor) or am I misunderstanding something here.

    nikV
     
    NikV, Oct 3, 2005
    #6
  7. Hi there,

    All I can say is that the image I have on my site is taken with a D70
    and a 105mm macro lens. The 35mm equivalent is 157 mm and the exposure
    was 1/250 sec @ F/11

    The image was taken at the maximum magnification I could achieve.

    The image is genuine, It is definitely a maximum sized image.

    I'll mount the lens on my F100 and see if I can measure the
    magnification.
    Bye for now,

    George Dingwall

    Invergordon, Scotland

    http://freespace.virgin.net/george.gdingwall/index.html
     
    George Dingwall, Oct 3, 2005
    #7
  8. Hi there again,

    I have found I had made a mistake when taking this image.

    I had the focus on "Limit". This meant the maximum magnification was
    restricted. I've re-taken the image and it now gives an image the size
    you suggest, I.E. about 24mm wide.

    The revised image can be viewed at this link;

    http://freespace.virgin.net/george.gdingwall/pages/test.html


    When attached to the F100, you get an image of about 36mm wide.

    Sorry for any confusion caused.

    Bye for now,

    George Dingwall

    Invergordon, Scotland

    http://freespace.virgin.net/george.gdingwall/index.html
     
    George Dingwall, Oct 3, 2005
    #8
  9. NikV

    PcB Guest

    << now I'm puzzled if the sensor was 35mm wide (I know its not) then surely
    at 1:1 the object (ruler in this case) should also be 35mm(smaller for a
    smaller sensor) or am I misunderstanding something here.
    The issue is not just the sensor size (well, sort-of, but read on anyway).

    Imagine the cone of light which the lens projects behind it. Then imagine
    the 35mm negative put into place where the lens' focal plane lies - the
    negative will just fill the circle so that all parts of it get enough light
    for exposure. Now remove the 35mm negative and replace it with a digital
    sensor, which is much smaller, and you will see that the sensor sits well
    within the circle (which hasn't changed size, of course). This means that
    the sensor will see a smaller part of the circle and, hence, will appear to
    magnify the image (by showing only a smaller part, which is what
    magnification is, anyway).

    Hope this helps ....

    Paul

    --
    Paul ============}
    o o

    // Live fast, die old //
    PaulsPages and Galleries are at http://homepage.ntlworld.com/pcbradley/
     
    PcB, Oct 3, 2005
    #9
  10. NikV

    GTO Guest

    More than 1:1 with a DX format image sensor? No. Not at all!

    Please check the definition of reproduction ratio in photography. It is
    independent of the size of your image sensor.

    The reproduction ratio is the ratio between the size on film and the actual
    size (see http://xoomer.virgilio.it/ripolini/Close_up.htm for more).

    Gregor
     
    GTO, Oct 5, 2005
    #10
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