Originally posted by Mooncatt I use to belong to a newbie photographer Facebook group, and the general consensus there was manually cleaning the sensor is rarely needed. If it is needed, it's a very delicate process that should be left to a professional shop. Since being on this forum, I've seen a lot more threads about this that I would've expected, and the discussions on it seem relatively benign on doing it yourself.
Is sensor cleaning really a common practice? If so, is it as risky as I was lead to believe?
Yes, it is common practice. No, it isn't risky if you follow the standard procedure, with tools specifically made for the job.
With sufficient lens changes, every camera body eventually gets to the point where the sensor has dust specs that won't dislodge from the in-body cleaning mechanism (SR or ultrasonic, depending on which Pentax camera body you have - I believe everybody else has ultrasonic or nothing at all (Canon EOS x000D line comes to mind)).
It gets interesting if you look into the details. There is a "pad" (don't remember exact term right now) that's designed to absorb and hold the dust that falls off the sensor during built-in cleaning. Over time, that piece of equipment, having absorbed more and more dust, no doubt eventually becomes less effective. It's also claimed by some that Olympus has the only thoroughly effective ultrasonic cleaning mechanism. I've personally found the SR-based one to work better than the ultrasonic one on Pentax cameras. Often, if something is stuck after the first clean on an ultrasonic-cleaning camera, it will remain stuck no matter how many times you drive the cleaning mechanism. With the SR-based cameras, I've found I can often get rid of all the dust if I just run the mechanism 10 times, maybe 20 maximum. But even that doesn't always work, and a manual clean will eventually be required.
Before you go in for a swab, try a dust blower as an intermediate solution. Dust blowing is a bit of a skill in that you want to get fairly close to where the sh*t sits, but you ideally don't want to be touching the sensor glass.
Some swear by the Rocket-branded dust blowers that are specifically marketed to photographers, others will point out that the special valve it has doesn't work very well. I've used non-photographic "blowers" with success. I believe some are made for picking up liquids but work just as well for blowing air, and they cost pennies. Just make sure it's the right shape to get it close enough to the sensor to be effective.
When blowing air at the dust you see in your pictures, remember that left is right and top is bottom - the camera inverts your image back to how you experience it (your brain does the same thing with your eyes), so make sure you understand where the dust actually sits. You could spend a lot of time blowing at the wrong spot.
It is my current opinion that lens pens are best reserved for working on lenses, if at all, so if the built-in cleaning mechanism and dust blowing both can't get the job done, swabbing is the next and last step.
You want to buy the special equipment sold through the usual channels. The pokey thing with the microfiber end (I believe that's a fair description - I shall additionally refer to them as "swabs" hereafter) comes in different sizes for different-sized sensors. The liquid stuff, often bundled with it, will typically last you a long time. The trick is to only use a minute quantity of it, otherwise you'll be using a lot of extra swabs to pick up the remaining liquid off the sensor glass. In my opinion, you should leave no residue in the camera if you can help it.
To that end, when you start, check that the swab wrappers tear smoothly. There is at least one brand that's a real joy to use - I don't have the name in front of me, sorry. If you need an extra swab, you want to be certain you can get to it and not start a fight with the wrapper.
Err on the side of using more swabs (i.e. pokey things) - if you use each swab for just one pass over the surface, meaning you need maybe two of them to cover the entire sensor, you're doing great in my book. If I were short on swabs, I'd consider using first one side then the other. You can certainly do that if the purpose is simply picking up liquid. The rationale is that you don't want to screech a sand grain over the surface of the sensor glass more times than you have to.
I may have gone into a fair amount of detail, but at the end of the day, it's really not that bad. You'll learn very quickly what to avoid, and how to fix things.