I understand that there're quite a few posts out there relating to sensor dust & black spot in viewfinder. Notwithstanding that, I'd greatly appreciate if you guys can assist me with some queries.
1. I am trying to test my d5300 for any sensor dust. Do I set aperture to, say F22, and shoot a white piece of paper? Do I have to focus on the paper? Also, if it's too dark, can I use a higher ISO setting? Would this affect the results?
2. I just noticed a black spot in my viewfinder which got me a pretty worried. My camera normally sits in my dry cabinet and the last time I took it out, there was no black spot. Took the blower to blow the viewfinder but the spot remains. Should I be concerned? I have never changed lens (18-140) so far, and it's placed in a bag if I ever do bring it out (though for overseas trips it hangs around me).