Not off-base at all Bruce. Scale it up and look at the fastest lenses for 4x5 or 5x7 film cameras. Same reasoning.
On Mon, Oct 6, 2014 at 8:33 PM, Bruce Walker <bruce.wal...@gmail.com> wrote: > On Mon, Oct 6, 2014 at 9:23 PM, Stanley Halpin > <s...@stans-photography.info> wrote: >> >> On Oct 6, 2014, at 4:26 PM, Larry Colen <l...@red4est.com> wrote: >>> >>> P.J. Alling wrote: >>>> and wonder of wonders it's got some interesting information for free. >>>> >>>> http://www.luminous-landscape.com/techniques/pentax_645z_astrophotography.shtml >>> >>> Excellent link, though I'm afraid that if I were to spend $10K on a 645Z, I >>> wouldn't have any money left over for the $500 astro mount. >>> >>> I was surprised to find that there don't seem any lenses faster than f/2.8 >>> available for the 645. Doing some quick web search, there don't even seem >>> to be any manual focus lenses faster than f/2.8 available. >>> >> >> There are adapters that support the use of Hassleblad etc. on the 645. Maybe >> you can find the faster glass you need by going that route? > > I always assumed that there isn't faster glass because there doesn't > need to be. The DoF on medium format is already razor thin compared to > 35mm and APS-C and perhaps a 1.4 on a 645z would create a serious > focusing problem? Or ridiculously OOF portraits? > > In other words, we have what's practical to sell, as with other > formats. Or am I way off base? > > -- > -bmw > > -- > PDML Pentax-Discuss Mail List > PDML@pdml.net > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- Photographers must learn not to be ashamed to have their photographs look like photographs. ~ Alfred Stieglitz -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
