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Message: <blockquote data-quote="WayneF" data-source="post: 184028" data-attributes="member: 12496">All of that sounds very normal for macro.  This 1:2 lens needs the added extension to become a 1:1 lens, on any camera, FX or DX.  Normally, when we photograph something, the subject is maybe 10 feet, or 100 feet, or maybe a mile, in front of lens.  The focal length suggests the sensor is 105 mm behind the lens (at infinity focus, but there are approximations and details of where this point is measured, probably near the front element in this telephoto case, but you get the idea).   And lets say 105mm is 1/3 foot.The ratio of the focal length, say 1/3 of a foot, to the subject distance, say 100 feet,  is the magnification of that image, how small the image is on the sensor or film (which is a great size reduction).  10 feet distance is 10 times larger than if at 100 feet.If we get 1:1 size magnification, that means the subject is as close in front as the sensor is in back (necessarily equal, at 1:1 magnification).  So yes, 2 to 6 inches in front of lens (called working distance) is reasonable for 1:1.  Same as the focal length, which gets longer focused up close (but again, where these points are measured from is not likely same as we would guess).The new 105mm f/2.8 VR macro lens is more like 6 inches (working distance, in front of lens) at 1:1.  The lens focal length also becomes longer too, to focus that close.Here is an excellent chart of the working distance of many Nikon macro lenses<a href="http://www.jeffree.co.uk/pages/macro-lens-calcs.html" target="_blank">Macro lens calculations</a>If I recognize your 105 f/4, it is near the bottom of the list, and says 272 mm, which is 10 inches in front of lens.  However, the chart states that is for the lenses 1:2, not 1:1.  1:1 will be probably about half of that (twice the magnification).</blockquote>

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