I noticed while editing/reviewing several of my photographs from some recent commercial/shopping shoots that I had a couple of sensor spots in the sky…a tell-tail sign that sensor cleaning was in order. Fortunately, I'm able to do my own sensor cleaning and began the process of determining just how bad things were so I could compare that to my finished work.
There are numerous sites that get into the details of how and why dust gets on your sensor, but simply put, removing your lens exposes the insides of your camera to the potential of contaminants. Don't be afraid to change lenses when you're out on photo shoots--just know that periodically you will need to address a dirty sensor.
You don't have to create before and after images of your sensor cleaning, but I find it rewarding to see the improvement. Taking the "before" image is fairly straight forward, although different people suggest different approaches. Basically you set your camera to a high f/number (like f/22) and then take a picture of something as clear and clean of detail as possible--straight up in the sky has worked best for me.
When you take that image into Lightroom's Develop module, your analysis starts by grabbing the spot removal tool, and then turning on the Visualize slider (and maximizing its effect). Below is what my sensor looked like before cleaning--wow, it sure was dirty! No worries though as this is normal.
Typically your camera will have a setting specific to enable sensor cleaning wherein the mirror is locked up out of the way giving you a clear shot to access the sensor. Then, depending on what cleaning technology/method you plan to use, your next steps are to simply clean the sensor. I happen to use a sensor gel stick and have had great results with it.
Once the sensor has been cleaned, you can return your camera to normal operating mode and you're finished. I like to go that extra step and check the results. Below are three images...the first shows my sensor before cleaning. The second image shows it after cleaning, and because I wanted to try and get every last spec, I cleaned the sensor a second time--and the third image shows a nearly perfectly clean sensor.
I’m a happy camper again and ready for my next photographic adventure!