Gear is meant to be used. Using your gear gets it dirty. That's just the way it is. Getting your gear cleaned occasionally is a good idea.
My Canon EF 24-105mm f/4.0L IS lens is probably my most used lens. It travels with me almost everywhere. It's light, has a great focal range, and produces sharp, clean images. Like I said, it's one of my most used lenses.
Like I said before, using your gear gets it dirty. Dirty gear needs to be cleaned. This lens was long overdue for a good cleaning. Long overdue. This fact was brought to my attention the other day when I took this shot.
Before I explain further, let me tell you a little bit about this image. This was shot the other morning in Valley of Fire State Park, just outside of Las Vegas, NV. It was a fantastic morning and the warm sunrise light plays off of the red rocks beautifully. One of the things I love about shooting a good sunrise is the starbursts that you can capture. These happen when a point of light (the sun in this case) peeks over a hard edge (the rock in this case). The points of the starburst are exaggerated when you use a small aperture with your lens. For this shot, I was using f/22. It worked beautifully, I got the results I was looking for.
Now, back to the original point of this post. The down-side to shooting at f/22, is that every bit of dirt on your gear will show up in your image. Don't believe me? Check out what I had to do to this image in Lightroom.
Use your gear. Clean your gear. It's that simple.