Pentax SMC D 16-45 Lens How to clean inside? Pictures are showing spots and all the outside lens have been cleaned along with the inside of the camera itself. Can not see the spots when taking pics only showing up after transfered to pc.

Your lens would need to be absolutely filthy with enormous dirt specks to cause the fault you describe. Dust, fingerprints, and regular minor debris simply doesn't show in the final image. In any case, you cannot clean inside the lens without dismantling it and that is a job for experienced specialists only.

Your fault is a dirty image sensor. You can buy sensor cleaning kits, but if you're inexperienced with them or trying to clean the sensor in a dusty environment you'll just make matters worse. Many camera shops offer sensor cleaning while you wait at relatively low cost. The reason you don't see the dirt when taking the picture is either because you're looking through the optical viewfinder or because the LCD screen simply doesn't magnify the image enough to show the marks which are present in the image.

You can prevent the dirt from reoccurring by never leaving the camera with the lens throat open for more than strictly necessary, and by always trying to keep the open lens throat pointing slightly down when swapping lenses.

I hope that I've helped, please take a moment to rate my answer.