Forum

Pages: [1]   Go Down
  Print  
Author Topic: Sharpness of Images  (Read 484 times)
Green Flash
Newbie
*
Offline Offline

Posts: 4


« on: November 24, 2013, 05:22:14 AM »

<div id="linkdxomark">This a comment for <a href="http://www.dxomark.com/Lenses/Camera-Lens-Database/Nikon/AF-Zoom-Nikkor-70-300mm-f-4-5.6D-ED">this page on the website</a></div>          
       I have this lens (i.e. the Nikkor 70-300 FX zoom lens), a Nikon D600 and a Nikon D 7000.  Recently I have been trying to take pictures of the moon. You rate this lens higher with the D 600 than with the D 7000, but I have been able to take much more detailed pictures of the moon and its many craters, with the D 7000 at full zoom than with the D 600. In fact the difference is stunning.
          So please try to help me understand why my images are more detailed with the D 7000 than with the D 600.
          I think the reason is this: At full zoom, the fx lens zooms to the equivalent of 450 mm on the dx camera. I think this comes about because although there are more pixels on the FX camera, the pixels on the DX camera are crowded into half the amount of space, so the actual density of the dx image is greater, so that the image of the moon includes more pixels from the dx camera, than from the fx.  
        The moon is actually pretty bright so there is enough light to fully utilize the dx pixels.  
          Thank you for your wonderful site.
« Last Edit: November 26, 2013, 06:59:26 PM by Green Flash » Logged
Emilie_DxOMark
Administrator
Hero Member
*****
Offline Offline

Posts: 530


« Reply #1 on: December 03, 2013, 04:38:05 PM »

Hello,

Thanks for your interest in DxOMark.

It is more a problem of focal : on the D7000 you had a 450 mm focal equivalent and on the D600 you only had a 300mm.
If you could frame the same moon part with the Nikon D600 this image would be sharper than the one you got with the D7000.

Best regards,

The DxOMark team
Logged
Green Flash
Newbie
*
Offline Offline

Posts: 4


« Reply #2 on: December 03, 2013, 08:26:36 PM »

           I agree with what you are saying, but the "IF" is huge. All through the zoom range, the D 7000 gets much more effect zoom than the d600, so it gives a clearer image because the greater effective zoom means that more pixels are devoted to any particular portion of the image.  So regardless of the comparative clarity ratings, if you are zooming max and then cropping you may get the clearer image from the lens using the d7000 if there is enough light. 
           But you are saying that if you dial back the zoom on the D7000 camera so that the full image is the same as the full image taken by the D600, then the D600 image would be clearer.  This is the situation covered by your comparative ratings of the same lens on different cameras.   
           Do I have this right? 
Logged
Emilie_DxOMark
Administrator
Hero Member
*****
Offline Offline

Posts: 530


« Reply #3 on: December 05, 2013, 09:54:17 AM »

Yes, that's right indeed Smiley

Logged
Pages: [1]   Go Up
  Print  
 
Jump to: