Wishful thinking alert: Pentax needs a system that will allow their DA*400 or 500mm lens to AF with a 2x extender. So, either reasonably fast glass or a much improved AF system that works well @f8-11 in low contrast dim light.
stan Sent from my iPhone On Aug 31, 2011, at 5:24 PM, Larry Colen <[email protected]> wrote: > I think that part of the reason that the adaptall mount went out of favor is > the difficulty and complexity of doing a screw-drive autofocus version. It's > one thing to make a linkage that'll handle f-stops, but the tolerance you > need for screwdrive would be really tough to pass through an adaptall style > mount. However, SDM is an electronic connection, not a mechanical one. For > that matter, you wouldn't even need a mechanical linkage for aperture, just > the stop-down actuator. > > I was contemplating that with sensors improving so quickly, that it's barely > cost effective to spend the money making fast glass, to get a stop or two, > when sensors will give that same speed in a couple years time anyways, for a > lot cheaper. Therefore, fast primes are going to quickly become a niche > market, especially in DSLR mounts, and that there probably aren't enough > Pentax mount DSLRs out there to justify the development costs of new fast > prime optics. However, it might be economically feasible for a boutique > optics company to make fast primes using something akin to an adaptall system. > > -- > Larry Colen [email protected] sent from i4est > > > > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
