How to clean your sensor Page 2
Have I got dust?
Spotting minor instances of dust can be tricky, unless you spend much of your time shooting white things. However, here’s a quick trick to reveal contamination. Set the aperture to a small value, such as f/16, then take a picture of a brightly illuminated piece of white paper. Transfer the shot to image-editing software and access the Levels dialogue. Ramp up the contrast of the image to an extreme setting and, if there’s anything that shouldn’t be there, it’ll show up as specks.
The first and most obvious means of combating dust is to take care of your camera, keeping the lens spotless and, if using a DSLR, being extra-careful when changing lenses. It’s a problem in any environment, but most especially when working in windy conditions. Make sure that the camera is switched off before removing the lens, as the electrical charge applied to the sensor when it’s on can attract dust. Keep the exposed camera body and lens rear-element shielded from the elements when the lens is off, and replace the lens as quickly as possible. Use the supplied body and lens caps to protect your gear when not in use.
Of course, even the most careful photographers may end up with specks inside the camera after a certain amount of use, whether foreign particles, or small specks coming away from the camera’s moving components. Even cameras with integral lenses are not immune to contamination at the manufacturing stage. In the latter case, take the camera back to the retailer for repair or replacement – there are no user-serviceable parts inside. If you’ve a DSLR, there are many professional cleaning services, plus a variety of DIY solutions, as we shall see.
Pro cleaning services
For those without the bottle to attempt cleaning a camera’s sensor themselves, there are professionals who’ll be happy to take on the job. Of course, it costs money and the price will vary depending on the extent of the clean-up necessary. The camera’s manufacturer will be able to service it for you, but even if it’s still under warranty they’ll charge you, as dust is a mainentance issue, not a fault (unless it was there when you bought it).
There are also loads of independent repair companies in the UK, many authorised by manufacturers to carry out work on their behalf, so track down those local to you via www.yell.com. Have a word with fellow photography enthusiasts too, to get their personal recommendations.
Sensor cleaning systems
Despite manufacturers’ efforts to bust dust with high-tech gadgetry such as static electricity and vibration systems, there’s still a ready market for camera-cleaning products and services. There can be few photography enthusiasts without at least a blower brush and some lens wipes at the ready. The advent of digital, however, brought forth a very different challenge to that of keeping optics clean – that of cleaning a digital SLR’s sensor.
It’s actually the wrong term. If there was dust actually on the sensor, that would be a disaster. As you’ll have gathered, the sensor is protected by an optical filter and this is what you’d clean. There are many options available to the DIY camera maintenance engineer, but it’s worth pointing out immediately that if you’re in any doubt as to your cleaning ability, or if the camera is under warranty, cleaning should be undertaken by professionals. It’s easy to wreck its internals with ham-fisted efforts, a common phenomenon being the mirror snapping down on a swab stem. You should at least know how to lock the mirror up before proceeding.
The most basic cleaning implement is the sensor cleaning brush, which has the advantage of simplicity, but isn’t so good for particles that have stuck firmly to the filter – sometimes called ‘welded dust’. Also, the abrasive action of the brush could cause damage. Anti-static brushes release dust held on the sensor by a static charge. Again, they may damage the filter if used without due care and attention.
Both blowing and sucking solutions are made by numerous manufacturers, and while they don’t physically touch the filter, they’re still not that effective on welded dust. Wet or sticky solutions that use solvents or adhesives are the most effective at removing stubborn grime – the former using solvents and swabs or swipes to shift the muck. But you should remember that you can’t take certain chemicals, such as methanol, onto an aircraft and you could end up leaving a residue on the filter. There’s a similar problem with using sticky tape. It’ll shift dust but the residue left by the adhesive could cause headaches.
Over the page, we’ve gathered together a number of the most popular sensor-cleaning systems, all using their own method. If you plan to have a go yourself, it’s also worth investing in a magnifying glass or a dedicated inspection loupe, to enable you to get a much better view of your cleaning efforts.