For users of digital cameras with interchangeable lens, dust can be a real problem. This is especially true for photographers who shoot at smaller apertures (large f/stop numbers). Why? Because the dusts are not sitting directly on the micro lens of the sensor but on the anti-aliasing (AA) filter. The typical distance between the AA filter and sensor surface is much greater than the size of typical dusts. At large apertures, the light rays that pass through different part of the lens surface can go around the dust and focus on to the pixel. The dust may not be visible at all or appears to be a fuzzy dot in your photos. When shooting at small aperture, the light is restricted and therefore more directional (coming through a smaller hole). It causes the dusts shadow to show up clearly and sharply in the photo.
It is not a good surprise when you come back from shooting then found out there are dark spots on the exact locations of your otherwise great photos. You cannot completely avoid getting dusts on the sensor even if you seal your camera in a air-tight bag. The moving parts on your camera and lens can also generate some particles. So, what are the options? Read More…
