Rob Studdert mused: > > On 23 Oct 2004 at 15:07, Shel Belinkoff wrote: > > > Hasselblad says the 22 Mpixels sensor is 37x49mm, which, if my math is > > correct, is slightly larger than two 35mm frames. In addition they say, > > "Thanks to its unique Double Duration Circuit technology (patent pending), > > the H1D runs more than twice as cool as similar digital camera systems, for > > cleaner images, true 16bit colour depth and double the battery life." Of > > course, I haven't a clue as to how accurate this all is, but I've no reason to > > doubt the claims at this point. > > > > http://www.hasselblad.se/products/level3.asp?secId=1135&itemId=3362 > > Having a slightly increased sensor area per pixel and cooling on the sensor > would I expect lead to a better signal to noise ratio so I assume they have > utilized a greater bit depth to take advantage of any extra information.
They also offer an effective ISO 50 at the low end. That quadruples the exposure time (as compared to the ISO 200 of the sensor in many of the DSLRs). That accounts for the remaining two bits (from the 14 bit I calculated before to the 16 bits they claim). They'd need to improve the signal-to-noise ratio (else quadrupling exposure time adds one bit of signal and one bit of noise), but lower power consumption would do that - most noise is thermal noise from the circuit elements. Halving the power consumption gets you most of that one extra bit back - certainly enough to justify the claims quoted above. I'm gratified to see that my guess as to what the sensor size would be turns out to be pretty accurate. I still think that 22MP is probably pushing it a bit at that pixel depth, but not unreasonably so.
