24mp in our future for d300 replacement?
So you believe the FX segment will go up from 1/10 of the whole Nikon DSLR sales to nearly 1/3? Where does this growth in FX sales comes from? An entry level FX D600 that will sell more than any other Nikon DSLR except the entry level DX model? Will most users of the D300(s), D90 and D7000 abandon DX for the more costly FX system? Why? And this in the ongoing world economy crises?
I've no doubts a " more affordable FF" will sell well no question about it.
But crop sales will always be far bigger overall in volume, wake me up when FF gets to £599 for a body until then it's crop that has the mass sales
Obviously, they are counting on picking up market share , from Canon in particular. But I don't believe that they can sell as many D600s as they think they can. My guess is that their projections are optimistic by as much as 50%. Unless they have a fourth DX camera in the wings, a 16 MP 8 fps successor to the D700. In which case yes, I believe that Nikon could hit 33% FX.
Thanks for taking the time to provide an excellent explanation on pixel ISO/DR performance.
Very well writen and informative.
No, because the 'well size', contrary to what is often believed by people who learned their sensor technology from popular internet sources, is not controlled by the 'size' of the 'wells'. In fact the 'size' of the 'wells' has little to nothing to do with it at all. What controls the saturation capacity of the pixel is the available output swing of the source follower transistor and the conversion gain. If you make the conversion gain higher by making the source follower transistor smaller, then the saturation capacity falls, inevitably. In a photographic sense, this has the effect of reducing the amount of light necessary to produce a given voltage at the pixel output, but at the same time it reduces by a similar amount the absolute capacity of the sensor to collect light. What it does in effect is raise the 'base ISO' compared with a more conventionally designed sensor.
So, for instance, suppose a design team made a 24MP DX sensor with a saturation capacity of 24ke- per pixel, 3 e- per pixel read noise and a 'base ISO' of 100, then used the same SF transistor design in a 24MP FX sensor they would end up with a sensor with a base ISO of 225, still 24ke- saturation capacity and still 3 e- per pixel read noise. The per pixel DR would be the same (8000 = 13 stops) Interestingly, if we compared the effects of taking the same photo using cameras with those sensors (same scene, AOV, DOF and shutter speed) then if the lenses were well optimised to the format you'd not be able to tell them apart, the noise (both read and shot) would be identical, as would the diffraction blur. One might ask what would be the point of having FX in that case - the answer is access to lower DOF, but that is the only advantage you'd get for the sensor size. Now imagine we take the FX pixel design and make it into a DX sensor, now we have 10.7MP, still with a 'base ISO' of 225, per pixel DR of 13 stops and 3 e- read noise. Now lets compare the DR of the two sensors at the same final image size. For sake of argument we'll use an 8MP image, such as an A4 print, as DxOmark does. The per output pixel Dr of the 24MP camera is 8000*√24/8 = 13856 = 13.76 stops. The output pixel DR of the 10.7MP camera is 8000*√10.7/8 = 9252 = 13.2 stops. The net effect is to reduce DR by 1/2 a stop absolute. However, if we compare the sensors at the same exposure the the larger pixel camera has a small advantage. Let's compare at 6400 ISO. The small pixel sensor will collect 375 photons per pixel for a per pixel DR of 375/3 = 125 = 6.7 stops. The large pixel sensor will collect 844 photons per pixel for a per pixel DR of 844/3 = 281 = 8.1 stops. Now, if we compare at the same output size (8MP) again, then the small pixel sensor give 125*√24/8 = 216 = 7.8 stops. The large pixel sensor gives 281*√10.7/8 = 325 = 8.3 stops. So the trade is we've lost half a stop in absolute DR and gained half a stop exposure for exposure.
So, we can estimate what would be the effect of making a 24MP sensor using the D800 pixel, namely a rise in base ISO of 1.5 times, to 150 (they'd probably call it 200 again), a rise in same exposure DR of log2 √1.5 = 0.3 stop. So there is a small ISO for ISO gain, at the cost of lower absolute DR.
The 24mp did not blow away the 16mp sensor
The trend has stopped on that one. More to the point I'm amazed Nikon are following this high mp strategy, even more annoying is the lack of small raw sizes.
Not in a $500 consumer camera it didn't. However, give the engineers some freedom with a $1500-$2000 D400 body and see what happens.
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