Putting the cranes to sleep

I really like this and love the way the K-50 puts out the colors. But I hate to tell you that you have something on your mirrors or lens putting those spots in the sky. I have the same problem sometimes and have to stamp them out.

I know, but am very fearful of going anywhere near the "capteur" (in English? - I've forgotten the word). Actually, with clouds, there are sometimes microturbulances which seem to be just spots, but which are really there.