Love your gear - What I learned from going to the service
For some time now I noticed that photos are not as sharp as they should be. They were not clear and it was like a fine haze on them. But usually only on half of the image, and they had some spots that did not want to go and appear in almost every photo.
I always had a protective filter on lens from the second it was out of the box. I tried to clean it by breathing on it so I can moisten it a little bit and after that use a soft cloth.
Don't do that !!! only if an emergency require you to clean it like that, the service man told me. He told me that I need to use only special solution for lens cleaning and after that use a microfiber cloth and wipe it clean starting in concentric rings from the center to exterior so the remaining residue should be pushed to the margins. Repeat that process with the glass on the other side.
But before you use the solution first use a blower to try and remove the dust, dirt from the surface of the lenses. After that use the special cleaning solution and the cloth but don't press to hard because lenses have a special coating that can be scratched and it will affect the quality of your photos.
He also found that the camera suffered a physical shock ( I might have been dropping it or smash it around in doors or walls when walking with it on shoulder) and because of that the sensor moved a little bit out of his position and that's why the camera was taking half of the photo clear and half a little bit out of focus.
Even if the camera and the lens were water and dust proof some dirt manage to make it way inside the camera and that why my photos always had some round spots in them. Even if i took care of them when I was shooting at Color Run in Bucharest, I guess some fine particle of that colored powder made it way in when I changed the lens.
So that should not happen you should always keep the camera body facing down in hand for those seconds that it takes you to change the lenses. If u keep it up, particle of dust can go in easily. Always put the bottom cap on lenses after u changed. Don't let them stay like that because dust can enter there.
If you see particle of dust, use a blower to remove it from the surface of the lenses and after that use the cleaning method described before.
Don't forget if you take photos near in places where the camera and lenses can be splashed or in rain to check first if your camera and lenses are water proof or you need some special protection to protect your gear. And if they get splashed clean them and dry them as soon as possible because water can infiltrate in your gear and make even more damage.
If you have trouble with the lenses communicating with the body, you might have dirty electrical contacts on the lenses. The best way to resolve this is to use a special solution that is made for cleaning contacts like Detoxic Gold or just plain old Isopropyl Alcohol with a clean soft cloth. Of course not always we have that on us and if we ever need it now and it can't really wait because u are in the middle of a shooting than you can use a Pencil Eraser.
But remember that this is not recommend because the eraser is abrasive and can easily damage the thin gold plating on contacts. You can do this only if in emergency and if you don't have backup equipment even if at an important shooting you should always have.
Remember that you should always take care of the equipment that you have and use and always carry with you in the bag a special cleaning solution for the lenses and the contacts, a microfiber cloth and a small blower so you can always have your camera ready to capture that special moment.
PS: I learned 1 more thing ... that it costed me around 150$ all the repair that could have been avoided if I had been more carefully and loving my gear more.