There s a small irregular black blob on all my pictures. What is it?
Dust on the sensor. Unlike film cameras, which expose a fresh chunk of clean film every time you wind the camera, digital cameras use the same glass sensors. And naturally dust on the sensor will appear in the same spot on every single photo you take. This problem will be more apparent if you shoot at a small aperture (larger f/ number) than if you shoot wide open (smaller f/ number). So sometimes shooting at a wider aperture setting will minimize the problem. But fundamentally you need to clean the sensor. And this becomes problematic, because the sensors are quite fragile and easily scratched. You don t want to be sticking paintbrushes or cotton swabs or whatever in your camera and wrecking the image sensor. Pressurized air bottles (technically gas under pressure, not air) also tend to leave residue, and are best avoided. Canon themselves recommend to use nothing more than a squeezy rubber blower brush to remove dust, but that doesn t always do it. A lot of people recommend special s
