by Bart Arondson

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In short, no. See What is noise in a digital photograph? for a fairly comprehensive overview of what does. The main aspect of a lens which might cause increased noise is if you are shooting at a reduced aperture and not compensating with a longer exposure — you'll have to increase the ISO, and that amplification will make more apparent noise. But if you're ...


I also think that it depends on the camera. Factors include the bit-depth of the A/D, the various sources of noise, and unknown details. With all the theory requiring possibly unknown parameters even if the model is right, the only thing to do is a real test. Assuming the histgram fits completely in the exposure so you aren't deciding which end to cut ...


It depends on the properties of the sensor in your camera. Raising the ISO setting means you amplify the signal before reading it out, this means your signal level is higher and thus read noise is lower relative to the signal, improving the overall signal to noise ratio. However Sony Exmor sensors (found in all NEX bodies, and many current Nikon/Pentax ...


Your webcam will be applying a threshold to the signal coming off the sensor and zeroing any values below the threshold. Since the darkest parts of the image are mostly noise anyway this scheme reduces bandwidth. Seeing as your webcam is basically erasing these values there is no way you can record a dark frame. If you really really wanted to you could ...


When using CCD and CMOS sensors, the distribution of the DC component of the sensor noise rarely changes with time (unless you plan on using your camera in extreme temperatures). This allows for effective factory measurement and calibration which allows them to measure and remove the dark frame automatically. So I don't think there is much use in trying to ...


What is probably going on has little to do with the camera sensor, per se. When the signal from the sensor is processed there is noise reduction applied. It seems that in the case of your webcam, the processor recognizes a "noise only" black frame and goes ahead and eliminates all of the signal to get rid of the noise.

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