I have a new Canon 5D Mark iii body.
For a Specific project I work on I usually use an iso 100 and exposure speed of 0.3 sec.
After examining my photos I noticed that I have a fixed noise spot on all of the photos.
As the exposure is longer the spot becomes more vibrant magenta.
Do you have any idea what is going on? and more important, how can i avoid having this noise.