Originally posted by Lowell Goudge Everyone needs to step back and recall that many manufacturers share design aspects etc.
The K28mm F2.0 is actually a Zeiss optical design and Pentax and tamron have in the past have codeveloped lenses
Why is anyone surprised about a similar optical design.
The differences can be coatings, weather sealing and build quality. And these can be important
The assumption since release has been that the lenses are identical.
I'm showing that they describe the optical design differently opening up for the (unlikely) possibility that Pentax actually sells one that has been tweaked with anomalous partial dispersion glass and other minor differences in glass types whilst maintaining the general optical design.
If they are identical its curious and something to be critical about that they describe the lenses so differently. Its also interesting to know whether Pentax is lying about materials or Tamrons is underselling their optics.