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Thread: what is going on when using a 1:1 macro lens?

  1. #1
    Senior Member denniskee's Avatar
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    Default what is going on when using a 1:1 macro lens?

    hi guys,

    there is this thread which i came across, with something i dont understand, felt i am oting in that ts's thread, so start a new one here

    http://www.clubsnap.com/forums/showt...88#post4808588

    my question is, when using a 1:1 macro lens on a crop factor sensor body, when shooing a 3.6cm horizontal line, what is the length captured "physically" on the sensor?

    1) 3.6cm
    2) 2.25cm
    Last edited by denniskee; 16th February 2009 at 12:02 PM.
    photography makes one sees things from all angles.

  2. #2

    Default Re: what is going on when using a 1:1 macro lens?

    The cropped size, of course.... you'd capture the middle 2.25cm of the actual 3.6cm image.
    Alpha

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    Senior Member giantcanopy's Avatar
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    Default Re: what is going on when using a 1:1 macro lens?

    The crop sensor will capture the middle of the image
    It is still 1:1 by the way if the macro can capture 1:1

    The concept of the cropping is still the same irregardless of wide angle / macro / telephoto

    Ryan

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    Senior Member denniskee's Avatar
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    Default Re: what is going on when using a 1:1 macro lens?

    so, can i say that the reason why the 1:1 macro lens seems to have bigger magnification on a crop factor body than on the FF / Film body is :

    the 2.25cm is stretched to fill up the size of a say, 5R while maintaining the aspect ratio of 2:3, compare to the FF body where the 3.6cm is stretch less to 5R while maintaining the aspect ration of 2:3.

    so it is not correct to say the macro lens magnification factor went up went up to 1.6:1. the increase is due to the above mentioned?
    photography makes one sees things from all angles.

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    Default Re: what is going on when using a 1:1 macro lens?

    Quote Originally Posted by denniskee View Post
    so, can i say that the reason why the 1:1 macro lens seems to have bigger magnification on a crop factor body than on the FF / Film body is :

    the 2.25cm is stretched to fill up the size of a say, 5R while maintaining the aspect ratio of 2:3, compare to the FF body where the 3.6cm is stretch less to 5R while maintaining the aspect ration of 2:3.

    so it is not correct to say the macro lens magnification factor went up went up to 1.6:1. the increase is due to the above mentioned?
    actually, yea, the magnification factor did go up

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    Default Re: what is going on when using a 1:1 macro lens?

    1:1 meaning what's in real life is captured on your sensor right? since your sensor is smaller , you capture a smaller region. still 1:1 i think.

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    Moderator ortega's Avatar
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    Default Re: what is going on when using a 1:1 macro lens?

    in relation to the final frame yes the magnification seems to go up
    as in it is easier to fill the frame

    in relation to a 35mm film frame then it is still 1:1

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    Default Re: what is going on when using a 1:1 macro lens?

    Quote Originally Posted by coolin View Post
    1:1 meaning what's in real life is captured on your sensor right? since your sensor is smaller , you capture a smaller region. still 1:1 i think.
    1:1 is in relation to a 35mm film frame. (like many other stuff in photography i.e- focal length) So, if you blow the sensor back to the size of a 35mm film frame, the object captured in the frame'll be > 1:1

  9. #9

    Default Re: what is going on when using a 1:1 macro lens?

    Quote Originally Posted by Daedalus Trent View Post
    1:1 is in relation to a 35mm film frame. (like many other stuff in photography i.e- focal length) So, if you blow the sensor back to the size of a 35mm film frame, the object captured in the frame'll be > 1:1
    Actually no. It's still 1:1 whether you are using a FF or Cropped sensor.

    Reason for this is the defination of 1:1 is that the subject will appear the same size on the sensor. Thus, on a FF sensor, an object measuring 3.6 cm will fill up the entire sensor length wise, on a cropped sensor, an object 2.25cm will fill up the sensor.

    Obviously if you compare the final image taken by say the 5D Vs the 40D using the macro lens, then you will see that the subject taken by the 40D is 1.6x larger than that taken by the 5D.

  10. #10

    Default Re: what is going on when using a 1:1 macro lens?

    Quote Originally Posted by Daedalus Trent View Post
    1:1 is in relation to a 35mm film frame.
    1:1 in relation to the size-of-subject : size-of-image on the sensor. It doesn't matter whether the sensor is big or small.

    If the sensor A happens to have more pixels per square cm compared to Sensor B, then when when imported to the computer, camera A will give a larger magnification of the subject than camera B. Image dimensions would be different, and is immaterial as long as other factors (such as subject distance) are kept the same.

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    Default Re: what is going on when using a 1:1 macro lens?

    The physical length of the image on the sensor will still be 3.6 CM but since the sensor size is smaller you will get a cropped line at 22.5cm (for 1.6X crop). Thats the physical size. Some may argue that the image will appear bigger on a cropped sensor but that's not the physical size on the sensor. You can still take a shot with a FF camera, crop it and print out. Tada.. you will have a bigger image.




  12. #12

    Default Re: what is going on when using a 1:1 macro lens?

    Quote Originally Posted by DeSwitch View Post
    The physical length of the image on the sensor will still be 3.6 CM but since the sensor size is smaller you will get a cropped line at 22.5cm (for 1.6X crop). Thats the physical size. Some may argue that the image will appear bigger on a cropped sensor but that's not the physical size on the sensor. You can still take a shot with a FF camera, crop it and print out. Tada.. you will have a bigger image.
    Should be 2.25cm not 22.5 cm...

  13. #13

    Default Re: what is going on when using a 1:1 macro lens?

    Quote Originally Posted by denniskee View Post
    the 2.25cm is stretched to fill up the size of a say, 5R while maintaining the aspect ratio of 2:3, compare to the FF body where the 3.1cm is stretch less to 5R while maintaining the aspect ration of 2:3.
    I think what matters more is pixel density, not sensor size, because when taking macros/birding we have to crop even with a 1.6 crop sensors: few subjects will fill up the whole sensor. Wastage for crop sensors is thus small.

    There's no point assuming that one prints the picture as it is on the camera. Otherwise, once can simply "emulate" a crop sensor in a full frame by easily cropping the picture to 1.6 and get all the "benefits" of a cropped sensor. This isn't exactly possible, because, for instance, 40D's pixel density is 3.1 MP/sq. cm while 5D2's is only 2.4MP/sq. cm. So, a given subject will have a pixel-wise smaller foot print on 5DII and lesser details if shot at the same distance, which is usually the case for macros, MFD being the limiting factor.

    So, if you take a picture of a tiny subject at MFD using both cameras and crop it to include only the subject, the cropped areas will cover exactly the same physical dimensions on both sensors, but larger pixel-dimension on 40D. How larger? sqrt(3.1/2.4) = about 1.1 times larger.

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