NX200 FW 1.04 Raw SRW Bits/Sample now 12

Started Mar 25, 2012 | Discussions thread
viking79
viking79 Forum Pro • Posts: 14,148
Re: 14 bits is useless data on most cams... (more)

paulhome wrote:

viking79 wrote:

14 bits is excessive data on most cameras and you are basically making extra bits of noise. A camera has a certain signal to noise ratio for each pixel, and you only need so many bits of data to sample that. If you sample more bits than that you are just getting noise, no useful data.

Eric

Do you really believe that ?. The whole point of raw is that you get as much data as possible and then take if from there.

The argument you make is more suited to a raw vs jpg situation. The extra 2bit of data will give you more detail in the shadows which may be the nosiest area, but its data i would rather have than loose. The you can choose to reduce the noise pp if you wish.

There is no argument 14bit raw is better than 12bit raw.

It is certainly not. Just because it is extra data doesn't mean it is extra useful data. You only need the number of bits necessary for your sensors read noise, you can look this up on the web if you want, and the engineer could calculate the number of bits needed based on the sensor specification sheet provide by the manufacturer.

You can calculate this using full well capacity in electrons of the sensel and read noise in electrons, and figure out how many stops of DR are even possible with that pixel, say it worked out to be 12.5 EV, well then a 14 bit would buy you just a tiny bit, but if it were 11.5, a 14 bit would buy you 3.5 EV worth of noise (no difference between a 12 bit and 14 bit in this case).

The smaller the pixels are, the lower the well capacity, the lower the DR per pixel, the less bits you need in your ADC.

There is no way a compact EX1 needs 14 bit RAW. It is useless, all that extra data is noise that should have never been quantized in the first place. If someone can show me a specification sheet with the read noise and well capacity, we could calculate it. My guess is Samsung doesn't give that out freely, and no way am I going to try to measure it.

Eric

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