1) The central maximum of the diffraction pattern is between the slits.
2) Shoot single electrons at the double slit.  The same diffraction pattern accumulates.
3) Any attempt to identify through which slit a given electron passes collapses the double slit diffraction pattern into two single slit patterns.
4) All of it works just fine using C60 buckminsterfullerene as the diffracted entity, MW = 720.6 amu, or a big molecule like phthalocyanine derivatives C48H26F24N8O8 MW = 1298.7 amnu.  

http://arxiv.org/abs/1310.8343

Tell us how classical physics allows a 1300 amu molecule to pass through both slits simultaneously.  Compare width separation to molecule size.  Now, the giggle,

5) Quantum eraser and quantum double-eraser experiments.  How does it know to be classical or QM at the slit when the decision is made after the slit?

Double slit experiment
Being a beginner, I can't see why I must choose an 80-200 over an 18-200. Are there scenarios where an 80-200 would be preferable over an 18-200?

I will be buying a D7000 soon and am looking at these:


AF Zoom-NIKKOR 80-200mm f/2.8D ED
AF-S DX NIKKOR 18-200mm f/3.5-5.6G ED VR II


but similar considerations would apply to other brands as well.
