It happens to us all, at first you don't notice it, then it begins to bug you,, finally it's time to do something about it. The devilish dust bunnies or sensor spots to give it it's more common name. So what can you do about? Well these days, there are plenty of options, from software removal to wet cleaning the sensor.
Before we go any further, I am going to give you the normal disclaimer, anything you do to your camera in order to clean the sensor, you do at your own risk. There is a multitude of information out there, some of it good, some of it bad. Do your research, make sure its camera specific, full frame cleaning is different from APS/C sensors and if in any doubt, get it done professionally.
So rather than give you specific instructions, I am going to detail some of your options for eliminating the dust bunnies. Lets start with software options.
Know your Animals, Bird or Dust Bunny
Software is never going to be the best option and will only be a stop gap, but if you find you have returned from a shoot and there is a monster gremlin in your perfect blue sky, it's not difficult to remove. In days of old, the classic Photoshop clone tool would be the favoured option but these days the Spot Healing Tool is the better option which along with the patch tool will solve virtually all your spot problems. The drawbacks, it labour intensive, although you may be able to create a batch command for it, because often the pictures you will be cleaning may be very different, you may well get inconsistent results.
Another software option that maybe available is built in dust removal. Some software such as Nikon's Capture NX, allow you to create a reference image in camera (usually by photographing a defocused white wall) and then using that image in the software to remove the dust. Again although this lends itself better to batch processing, it is not an ideal solution.
So we come to the hardware solutions. Before you attempt any of the hardware solutions, read your camera manual and follow the instructions for opening the shutter and accessing the sensor. Also make sure you are in a dust free environment, and you operate with the camera face down. I mount mine on a tripod and work underneath it.
The first line of attack it a blower. Not a blower brush, just a powerful hand blower such as the Giotto Rocket Air. This works by blasting air over the sensor to clear the dust. Blast the blower several times before you work on the camera, to clear any dust in the nozzle. This may work for light dust that has not stuck to the sensor although you may just end up chasing the dust around the mirror box and not removing it. If going the blower route, a word of warning, never used compressed air cans, these contain chemicals that may damage the low pass filter in front of your sensor.
The next option is a static charge brush such as the Arctic Butterfly range. These use the static electricity on a fine brush to remove the dust from the sensor surface. Some photographers swear by them, but personally I have never had much success with them.
The most common option for professionals is known as the wet/dry swab. Here you use a specially designed lint free sensor swab that has been moistened with a cleaning agent. This is wiped in one direction over the surface of the sensor then repeated with a dry swab to remove any excess fluid. There are a number of companies that produce these, nearly all are not cheap, but they are in my opinion the most effective way of cleaning the most ground in spots from a sensor.
There are also a number of home made remedies available out there, I will not mention them by name, you can do the research on them. Again the most successful I have found have been based on the swab system.
So how do I check how successful my efforts have been. Well the best way here is to shot a plain white subject, a wall or piece of paper at a very small aperture i.e. 16 or 22 and defocus the lens. Import the image into Photoshop and apply the auto levels. You may be amazed or dismayed at the results but if you keep plugging away, you will eventually banish the vast majority of dust bunnies.
Needs More Work
As a footnote, I should mention that I have been cleaning my own sensors in Nikon D200's D2X's and currently a D3 for many years. Although I have sometimes made the dust worse, I have never damaged a sensor. As mentioned earlier, you do not actually touch the sensor, it is covered with low pass filter and this is made of pretty tough glass. You are much more likely to put smears on it rather than scratches, but as mentioned at the top of the article, do your research and if you do not feel confident, get it cleaned by a professional.
Jason Row is a British born travel photographer and filmmaker now living in Ukraine. You can follow him on Facebook or visit his site, The Odessa Files. He also maintains a blog chronicling his exploits as an Expat in the former Soviet Union