05-29-2015, 02:49 PM
(This post was last modified: 05-29-2015, 02:52 PM by Brightcolours.)
The old 50mm f1.8 has a bigger MFD. For the new one, with the same optics formula, to have a smaller MFD, the lens has to push the optics out more.
Old lens, MFD 0.45m:
![[Image: lens.jpg]](http://www.opticallimits.com/images/8Reviews/lenses/canon_50_18_5d/lens.jpg)
New lens, MFD 0.35m:
![[Image: lens.jpg]](http://www.opticallimits.com/images/8Reviews/lenses/canon_50_18stm/lens.jpg)
And the reason for these 50mm Canons to extend is the same as for the macro lenses you refer to. They are not IF designs.
Old lens, MFD 0.45m:
New lens, MFD 0.35m:
And the reason for these 50mm Canons to extend is the same as for the macro lenses you refer to. They are not IF designs.