Originally posted by RaduA You are kind of wrong again because in earlier roadmaps there was a DFA 645 55/2.8 even though there was no digital 645D. Even more there was a target of availability of around the launch of 645D. So this could be applied to FF lenses let alone the simple fact that a newly produced FF lens could be use fully on an APS-C camera. And of course the fact that on the roadmaps there are in clear 2 DFA lenses (50 and 100 Macro).
Old DFA have an aperture ring and may be construed to work with film. 60-250 has no aperture ring and cannot be used easily with a film camera, thus the use of the moniker DFA is somewhat flawed in reference to the 60-250, but the fact it
was there suggests it is designed to cover the full 35mm frame. Why build a crippled lens for a film camera? They wouldn't. Random guess then what it could be for?
Originally posted by RaduA: I am still waiting for some facts behind this statement.
Radu
You don't have to wait for proof, just have a look for M42 on Canons out there (and the D3 too) and the Takumars (for one) are very highly regarded.
There is no question some changes in multi-coating have optimized how light interacts with a digital sensor, but that doesn't affect vignetting, MTF or basic optical design. This current domination of APS-C digital sensors is a small drop of time in a bucket over 100 years old. Many optical formulas were conceived starting from the late 1800's and have only seen tweaks since then. The Carl Zeiss Planar was first produced in 1896 and is accepted as one of the most distortion free and brightly lit optical formulas in existance. The rise of digital has done nothing to improve this specifically, just alter the coating.
I don't mean to be personal, I'm sure we're all good folk. I just sometimes read in here that people seem personally invested in their guess about what Pentax will do even against logic. Lets just see what happens, and none of us will need to eat our words.