Sensor Dust and Basic Camera Care

When stored, handled and used properly, a camera lens and photo gear in general can last a lifetime. Several things can go wrong when small things are ignored that begee big issues over time - both the optical geponents and the mechanical aspects of your gear can be affected adversely, sometimes irrepairably. Here's a quick review of some of the basics in camera care:
First off, a list of "Do's":

Keep a Skylight filter on the front element of your lens. It protects the glass from debris andscratches. The ring can absorb a light ding and be replaced if your camera "slips". A ding on the filter thread of the lens will require repair or worse. If you are shooting with high quality glass, use a nice quality filter. If you are shooting in challenging lighting and concerned with flare, you can always remove the filter for the shot and then replace it.
Keep your lenses clean and use proper lens cleaning equipment and techinique.
Keep the lens cap on the front element at all times except when taking a photo. Keep both front and rear caps on your stored lenses.
Keep your lens and gear out of extreme temperatures and humidity. Do not leave photo gear in a car on really hot days.Some experts suggest storing your gear in a sealed plastic bag when bringing it back inside to warm up after being exposed to cold. This keeps condensation off the gear.
When storing your gear, do so at or near room temperature, in controlled lowhumidity and ensure it stays dry. If it is wet, towel dry andleave it out untilmoistue has had a chance to evaporate.
Use a camera strap. Loop it around your wrist before gripping the camera or keep it around your neck . If you drop the camera, the looped strap should saveyour gearfrom dealing with the more serious effects of gravity.
Always treat your camera and gear gently. Never force anything, whether it be a lens mount, filter thread or USB connection.
If you live in a tropical environment (high humidity), you should consider storing your gear with dessicant to assist in absorbing moisture.
Always take out the batteries prior to storing your gear. This includes the camera body, flashes and any accessories. Acid leakage has destroyed more than a few pieces of camera equipment.
With DSLRs, keep lens changes to a minimum and make your lens change quick. Hold the camera with the lens openingfacing downward. This prevents dust from settling inside the mirror chamber. Change lenses while the camera is turned off. These stepswill minimize dust contamination of the CCD, a gemon problem.
Try not to change lenses in windy, sandy or salty environments, eg. the beach.
Don't: (pretty much the opposite of the above list)
Now, the "Don't"s (pretty much the opposite of the above list)

Never allow your gear to get wet. Dry it immediately if it does, and allow it to air dry indoors prior to storing.
Never store it away wet. Metal can rust and seize parts; fungus can grow on glass and inside the lens.
Never store your gear in a way that items contact each other directly. Gear will scratch and wear when rubbing against each other inside a camera bag.
Never mishandle or treat your gear roughly.
Never take your gear to the beach...ok, you have to, but keep lens changes and exposure to heat, wind, sand and sea salt to a minimum. This stuff will wreak havoc with just about every aspect of your camera gear. Just one splash; a few drops of seawater will smoke off a digital camera. Trust me on that one....Sand grains will get just about everywhere and I don't mean just in your bathing suit. Sea salt can cause corrosion on metal and electrical contacts.
Never store your gear for long periods with the batteries installed.
Never use solvents on your gear, or gemercial glass cleaners on your lenses. A lightly damp rag is usually sufficient. You can add a drop of dish soap to the rag to help cut grease from your hands. Use only lens cleaning solution and tissue/microfibre on your lens glass,but first, use ablower brush to remove any grit.
Sensor Dust
DSLR's (like the Sony A100 and KM 5D and 7D) need special care to prevent dust contamination of the sensor. If you've downloaded photos and noticed small round dotsall overyour photos, particularly in the sky of your image, then you've got dust! You may notice it in only some pictures, because it shows up moreso when you areshooting witha smaller aperture.
You can reduce sensor contaminationby doing the following:

minimize lens changes (that is a tough one, after all, what is the point of having asingle lens reflex camera?!)
do not change your lens in a windy or dusty environment. As soon as you open up your camera, it is ripe for contamination. The beach, with sand and sea spray is the last place you should changea lens on any camera, nevermind your expensive DSLR.If there is no wind and no one is shaking out a beach towel nearby, I would take the chance and quickly change lenses to get the shot, though.
when changing lenses, point the camera towards the ground. Any dust and bits should then fall out of the camera rather than settle inside.
ensure your rear element is free of dust and contamination prior to attaching it to your body during a lens change.
DO NOT leave your camera power ON while doing a lens change. CCD stands for "Charge Coupled Device". Your sensor is a dust magnet when it is "charged" with the camera turned on - don't open up your camera with the dust magnet "ON"!
You might think your shutter (covering the sensor) will protectthe sensor from dust and it does, right up until you press the release to take a picture. The sensor is then exposed and charged up, attracting any loose, floating dust particles that have entered your sensor chamber.
"How do I know if my sensor is clean?"
Chances are, if you are concerned about sensor dust, you've already found a blob or two (or more!) on yourimages.
To check your sensor, the first thing to do is take a picture! Actually,you need totake a picture of a blank sheet of paper.Use your flash, with a stopped down (f/16, f/22) aperture and a fairly close focus lens. Try to fill the frame with the paper sheet so that all you get is a blank, white image. You may need to increase your flash setting to get a good exposure. You may need to manually focus due to the lack of contrast.
Downloadtheimage of the paper on to your monitor, and magnify to 100%.Review the entire image - you'll likely still see some dust spots. Larger dots (3-5mm) will be pretty obvious already on your regular pictureimages, but smaller dust spots may not show. If you've already detected dust in your regular images, performing this test will confirm the location of the dust and the also map out the degree of contamination. Remember, what you see on the image is flipped gepared to the dust locations on your sensor. Left to right does not change orientation, but top to bottom is reversed.
"What do I do, now that I have dust on my sensor?"
Non-contact sensor cleaning is very easy and safe if done properly. Work carefully and deliberately. You need a good bulb blower (no brush attached) to generate a sizable blast of air. The little silver dollar sized blower you got for blowing dust off your lens is not big enough. There are several blowers on the market that are bigger and more appropriate. Do not used "Canned Air" to blast your sensor as itcontains propellant that will totally mess up your camera's insides.
Proper Sensor Cleaning Procedure:
Step 1
In a well lit, dust free environment, preferably indoors, remove your lens from your DSLR (camera is turned off!) Point it towards the ground and while holding it so you can see upinside to the shutter plane, use your blower to squirt rapid blasts of air inside the mirror chamber, (taking care to not bump anything with the bulb tip!) then reattach your lens. You have just NOT cleaned your sensor. What you have done to this point is hopefully removed any contaminants from the mirror chamber. I use a halogen desk lamp pointed upwards so that I have plenty of light and can visualize the inside of the camera and don't inadvertently get too close to the shutter or mirror.
Step 2
Now follow your camera's instructions (in the manual) for putting your camera into "cleaning" mode and follow these instructions to the letter. This process releases the shutter and exposes the sensor so that you can repeat the previous instruction step and blow air across the sensor, hopefully releasing any dust that is attached to the sensor. Ensure that the tip of the blower does not touch the sensor.
Step 3
Repeat the "paper test" and gepare your new, hopefully cleaner image to the original test shot. If there is significant improvement indecreasing the amount and size of your dust contamination, you can now go take a picture ofblue sky at f/22 and see if your original dust dots are gone from a "regular" photo. If your image is clean, then your sensor is clean enough. If you still see dust in your regular images, you'll have to repeat the cleaning process. Sometimes it can take a few attempts to be successful. Your serial "paper test" images will give you a reference map of whether you are making any progress in subsequent cleaning attempts. You'll never get all the dust off the sensor and even if you did, it would eventually reaccumulate, so only clean your sensor to the point that your photos are clean.
Sweeping and Cleaning
If after several attempts, there are dust spots that haven't moved, it is likely that these are firmly attached to the sensor.
To remove stubborn, or "glued on" dust particles you will need to "sweep" your sensor with a brush, andpossibly "wipe" it with a moist pad. I occasionally "sweep" my sensor with a fine synthetic 1/2" art paint brush that I picked up at a craft storeto try to remove particles, but I do not advise you do this until you have done a thorough research on the web for this procedure. You can causedamage by scratching the glass filter that is in front of your sensor if you are not careful. I make sure my brush is blown clean prior to sweeping, and blowboth the brush and the sensorafter each attempt to clean. (I don't use the brush for anything else!) I repeat the "paper test" to check my progress. Because my brush does not have a static charge to attract dust, mostly I am moving dust around the sensor, but sometimes this is enough, coupled with the blower, to dislodge stubborn particles.
If sweeping doesn't work, and you've still got dust blobs affixed to your sensor, it's time for a moist wipe. There are gemercial products advertised on the internet and in camera stores for brushing and wipingyour camera's sensor, including Visible Dust, Artic Butterfly and Sensor Swab. A quick google will send you off to readreviews of these products and others, their pricing etc.
I've made a simple swab with lens cleaning tissue on the end of a wooden coffee stir stick and applied a drop of lens cleaning fluid or isopropyl alcohol to the tip - just enough to make my swab damp, not soaked.A couple of swipes (gentle pressure) with it, then repeated with a dry swab to collect any moisture and finally some air blowing to remove any paper fibres can work wonders. I do not regemend this procedure as I don't want to be somehow responsible should you toast your sensor! But if you've got the cajones to try it, make sure you have done a little research, and working methodically and carefully, minimize your pressure and amount of contact with the sensor. A couple of swipes, enough to cover the surface area of the sensor once should suffice. Back to the "paper test" and you can check your work.
Again, remember that you won't get everything off the sensor - once you've got this far with your cleaning, try taking a photo of blue sky at f/22 and check your image for spots. If your image is clean, it's "mission acgeplished".
Summary
Those are some of the more gemon sense things you can do to take care of your gear. We tend to tuck our camera stuff away for extended periods and a lot of nasty things can destroygear while it sits in the closet! The worst environment for your camera gear includes moisture, warmth and darkness. You might not recognize your camera after it has sat in the closet for six months in those conditions.If you are lucky, the damage will be cosmetic only.Unfortunately, battery corrosion and fungus growth can cause permanent damage. And sensor dust can be frustrating! The last thing I want to do is "spot clone"a weeks worth of vacation photosto get rid ofdust spots! A little maintenance prior to your trip or next shooting session will reduce the post-processing work afterwards.
Occasionally, unethical or simply unknowingokay sellers willlist camera gear onokaythat has not been properly stored or cared for. Read my gepanion guideto this one, titled "How to Detect Flaws in Used Camera Lenses onokay"that gives you the knowledge and skill to identify lenses which have been mistreated or stored in adverse conditions before they show up in your mailbox. Based on my own early-on okay experiences, it is required reading prior to bidding for a used lens on okay!