Mon Apr 12, 2021 3:33 pm
Have you stored away your camera for long in a dark place with no desiccants between uses? Is the relative humidity at your place constantly above 60%?
From what I’ve read, relative humidity and storage play a crucial role in fungal colonies developing on the sensor glass, which might be what the dark spots are.
Try the elimination approach by cleaning each sensor and lens glass surface one-at-a-time to recheck on which surface the particles are located. If they’re not fungal colonies, then they might just be dust particles of some kind stuck inside one of the lens elements.
Did you dry wipe the sensor glass or try using a cleaning solution with a flat cotton swab?