I have taken about 20,000 shots since last June and change my lens out multiple times a day when I use it. I finally bought a cleaning kit the other day and when I was doing some clean up I seemed to have blown some dust on to the sensor. I ended up with little black spots on my pictures that I never even had to begin withI was able to get the dots clear for the most part but I noticed my shots are noiser than normal at 400 ISO. Shooting at 200 ISO is noise free. This kind of concerns me as I usually don't see ANY noise until at least 800 ISO. I am kind of bummed as I just got Polarizers and UV filters for both of my lens' too. I really don't want to mess up my camera 1 month before we're off to New Zealand. So I hear I am not supposed to use compressed air. This is because if you turn the can a certain way some liquid can squirt out correct? Thanks in advance.
Dave