It's area that matters for how many pixels you can stuff in there, and thus the resolution. Using the pixel density of the ~12MP Nikon D3, at 118 pixels per mm, a 42x56mm sensor would be 32.7MP. Linear differences don't really indicate the actual resolution differences, because they only indicate one of the two dimensions that matter.Oh, and that sensor will be 9 times more expensive, not 4 (Sensor cost scales roughly by the square of the area, once again, that's what matters).
645 is natively 4:3 format Cropping 35mm down to 4:3 (24x32mm frame) gives 768 square millimeters, while 56x42mm 645 format gives 2352 square millimeters, for 3 times the area, the linear size differences matter little. Cropping 645 to 3:2 looks better for 35mm, but not by all that much (2090 square millimeters, and 2.7x the area). -Adam On 12/5/07, graywolf <[EMAIL PROTECTED]> wrote: > Area is only meaningful to advertising copy writers. > > Presuming you are happy with a 3:4 image 645 is 1.75x the size of 35mm, if you > want 2:3 it is 1.55x. So a full 645 format will allow about 1-1/2 times the > resolution of a full frame 35mm. That is assuming a 42mm x 56mm format and the > same ppi for both. > > But looking at it another way you can have bigger pixels, so at the same > resolution for both you can have 2+ times the sensitivity. > > In either case the larger sensor is going to be about 4 times as expensive. > > There are always trade offs involved. > > Graywolf > Website: http://www.graywolfphoto.com > Blog: http://www.graywolfphoto.com/journal/ > > Adam Maas wrote: > > Yes, but the native resolution numbers aren't that much lower unless > > you're looking t older lenses, and the area is a whole LOT larger. 645 > > alone has 2.7 times the area of 35mm. That's a lot of space to put > > pixels in. MF digital is comfortably up to 39MP now and there's likely > > room for more. > > > > -Adam > > > > On 12/5/07, P. J. Alling <[EMAIL PROTECTED]> wrote: > >> Actually, IIRC, with few exceptions, medium format lenses have lower > >> native resolution figures that 35mm. They don't need it due to the size > >> of the photosensitive surface they're projecting an image on. > >> > >> Adam Maas wrote: > >>> I dunno about that. The 1DsmIII is pushing the limits of what 35mm > >>> glass is capable of. While a ~22MP 645D wouldn't necessarily compete > >>> well (Although the Mamiya ZD back is selling every unit Mamiya can > >>> push out, at a similar cost to the 1DsmIII) a higher-rez unit might > >>> well be competetive, and there's a lot more resolution headroom with > >>> good MF glass. > >>> > >>> -Adam > >>> > >>> On 12/4/07, P. J. Alling <[EMAIL PROTECTED]> wrote: > >>> > >>>> An interesting user review of the new Canon 1Ds MkIII, which confirms my > >>>> feeling that the 645D was swimming upstream without the spawning > >>>> possibilities... > >>>> > >>>> http://www.luminous-landscape.com/reviews/cameras/mada-iiis.shtml > >>>> > >>>> I would consider this very bad news for an eventual 645D if it were ever > >>>> introduced. > >>>> > >>>> -- > >>>> The difference between individual intelligence and group intelligence is > >>>> the difference between Harvard University and the Harvard University > >>>> football team. > >>>> > >>>> -- P. J. O'Roarke > >>>> > >>>> > >>>> -- > >>>> 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. > >>>> > >>>> > >>> > >>> > >> > >> -- > >> The difference between individual intelligence and group intelligence is > >> the difference between Harvard University and the Harvard University > >> football team. > >> > >> -- P. J. O'Roarke > >> > >> > >> -- > >> 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. > >> > > > > > > -- > 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. > -- M. Adam Maas http://www.mawz.ca Explorations of the City Around Us. -- 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.
