SENSOR SIZE & IMAGE QUALITY
|The more light a sensor can collect, the better the image quality it can produce. That's because photonic noise (the noise carried by light itself, and the main source of noise in most digital images with current cameras) increases as the square root of the signal. In other words, if you have 4 photons of signal, you'll get 2 photons of noise (2 being the square root of 4). The resulting S/N ratio is 2:1. If you have 100 photons of signal, noise would be 10 photons, and the S/N ratio would be 10:1. If you have 10,000 photons of signal, you'd have 100 photons of noise, for a photonic S/N ratio of 100:1.
Of course, things aren't that simple. Given the same exposure, a full-frame sensor will collect more photons than a smaller sensor, due to its larger area, and produce a better S/N ratio, and better image quality. But to get the same field of view with the full-frame camera, you have to use a lens with a focal length 50% longer than the lens on the APS-C camera.
If you stop down and shoot at the same shutter speed, the sensor will receive less light (1/500 sec. at ƒ/8 delivers more light to the sensor than 1/500 sec. at ƒ/12), and the S/N ratio will thus go down, negating much of the larger sensor's S/N ratio advantage. In order to maintain the same image brightness and the same depth of field, you'd have to shoot at a longer shutter speed with the full-frame camera, which could be a problem when shooting moving subjects or handheld.
Wednesday, January 30, 2013
Is It Time To Go Full-Frame?By Mike Stensvold Published in SLRs
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Full-frame DSLRs are hot! The reasons?
For many years, the two most popular types of digital cameras have been compact models and digital SLRs. Each offers advantages over the other.
All-in-one zooms that can cover wide-angles to telephoto