When is 50mm NOT 50mm?

they are quoting the actual focal length. you have to add in the crop factor of 1.5 to get your equivalent field of view on APS-C Nex cameras. this only matters really if you have experience with certain FL lenses on 35mm or full frame digital. if you've only ever shot APS-C then the focal lengths are going to seem familiar to you because the angle of view is the same.  DOF is the same, but if you switch to FF  you will notice the FOV changed but you will still have to select the same FL to get the depth of field you wanted from your APS-C experience.  It might seem shorter but that's only illusion because the wider field of view makes it seems so.

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http://www.daisyseyecancerfund.org/Files/Awareness/photographing_rb_poster.pdf