Pentax makes in limited or asterisk lenses not compromise, the lenses are supposedly handmade. Clear about costs, but you also get so a well-tested product. The By testing was forgotten in my "Pentax SMC DA 16-50 f2.8 (IF) SDM" probably.
Absolutely not properly:
- For added meaner open aperture of the focus almost 2 cm was 16mm, at close range behind the focused area and sat until 24mm in the correct position.
- The CA (Chromatic Aberration) or colored edge glare that existed despite Lens Hood, I'm in such a severity never seen and would like it ever again.
- The CAs were continuously from 16mm - 50mm available and weakened until from f4.0.
- In addition, random depth at 16mm -24mm.
really nice
+ The brilliance and sharpness (if available)
+ The weather resistance
Conclusion:
After extensive crisscross read in various forums that report similar, I guess that should not be built as f2.8 this lens - from f5.6 it could work with 16mm-50mm without nasty side issues.
For me, rather more fixed focal lengths.