Today while goofing around, i decided to see if my lens spots were actually dust in the lens or on the sensor. so i took off the lens and took a few pictures in med to low light and got the following horizontal lines. Is this normal?? Do you get these?. After this i checked some blue sky images with the lens on, and they are not noticeable unless i zoom into 400% or so then i can just notice them among the noise.