Yes, with film there is the Schwarzschild-effect which causes the sensitivity and the color reaction vary with the exposure time. While digital camera sensors

Yes, with film there is the Schwarzschild-effect which causes the sensitivity and the color reaction vary with the exposure time. While digital camera sensors usually pick up noise for long-time exposures, this is less an issue for astronomical cameras, because they fight this noise by cooling the CCD-chip. Usually the chip is cooled via a Peltier-element to temperatures below -20C, where thermal noise is very low.