Hi Jens I made some good photos with the Tokina 28-70mm SD 3.5-4.5 on the SFXn , maybe this is not the same formula as the Tokina you mentioned?
I like the Pentax A Zoom 4.0 35-70mm too because it can focus much closer than the Tokina with 0.7m and has a constant aperture of 4. I liked the "3d-ness" on some of the landscape photos made with the Tokina. greetings Markus >>- >>I just tested three consumer zoom lenses: >>Pentax SMC-F 3.5-5.6/35-80mm >>Tokina 2.8-4.3/28-70mm >>Tamron 3.5-5.6/28-80mm Aspherical >> >>The Pentax-F (for which I have paid 31 USD + shipping) simply >>beats the crap >>out of the two others. >> >>

