Tuesday, May 4, 2010

What do I do about those dust spots on my digital photos?

Zeeion BlowerIn recent months, numerous readers sent emails to me about dirt and dust problems on their photos. They had cleaned their lenses, but the spots remained. They examined their DSLR’s sensor/filter and saw little specks of dirt, and asked what they should do.

You can generally remove spots during post processing, but it’s better to not have the problem to start, as sometimes “Photoshopping” doesn’t work particularly well.

Newer DSLRs have dust removal systems, like the Nikon D700, but while these cleaning systems do a credible job, they aren’t a 100% effective.

Repair shops, and manufacturers offer “professional” cleaning services, but they’re often expensive, some charging $150 or more, and it can take as long as 3–4 weeks to get your DSLR back.

Cleaning a DSLR sensor is not particularly hard. There are a series of progressive steps to take, which are generally fast, easy, and effective. You move from step to step, based on how stubbornly the dirt and dust resists removal.

You will need to purchase some supplies and equipment, but they will cost only about the price of a couple repair shop cleanings. Using zoom lenses extensively, and repeatedly making lens changes, over the last few years, I’ve had to clean my sensor at least twenty times.

The basic DSLR sensor cleaning steps are:
  1. Cleaning the sensor and sensor compartment with blown air,
  2. Cleaning the sensor with a statically charged brush,
  3. Cleaning the sensor with a non-film forming optical cleaning solution.
Tip: Every cleaning step requires you to have adequate illumination of the camera’s sensor so you can see precisely what you’re doing. If you can’t see clearly, you can permanently damage your DSLR.
Cleaning the sensor and sensor compartment with blown air:

The Giottos’ Rocket Blower, a hand-held squeeze air blower, has been the top choice for years. Remove your lens, lock your mirror up to expose the sensor, and while holding your camera with the lens opening pointed down, use the blower to blow out any accumulated dust from the sensor and the overall sensor compartment.
Tip: Locking up the mirror on most DSLRs can deplete the camera’s battery quickly. If your DSLR can be plugged into an auxiliary power supply, do so during the cleaning process. If the mirror unlocks while you are cleaning your sensor, it could result in serious damage to your DSLR.
Never let the tip of the blower, or any part of it, touch your camera, and especially your camera’s sensor.

This is your first line of defense to remove dust and dirt from your DSLR’s sensor. Even if this doesn’t completely clean your sensor, your should blow it out each time you clean. This eliminates sensor dust problems more than 90% or the time.
Tip: Don’t use canned air, as it uses propellant which can damage your sensor. Some CO2 canister blowers contain lubricant which could damage the sensor, however, there are CO2 canister blowers which can be used instead of the hand blower, as they contain no propellant, or lubricant.
I use a blower from Visible dust; the Zeeion Blower. This blower shoots out statically charged air molecules which neutralize the dust’s static charge for easier and more efficient dust removal. The Zeeion Blower costs more, but it’s worth it.
Tip: Make sure the outside of you lens and camera are as clean as possible before you remove the lens for sensor cleaning to keep more dust from entering the camera.
Cleaning the sensor with a statically charged brush:

The SensorSweep brush, the standard for years, is constructed of filaments which won’t damage the sensor while removing dust and dirt. Prior to its use, blow air through its tip to clean it, and build a static charge on it. This aids the brush’s ability pick up dust particles on the sensor.

Remove the lens, and lock up the mirror. With the camera facing up, brush the sensor clean with gentle strokes in one direction only. Re-charge and clean the brush every 2–3 strokes.

Arctic ButterflyI use the Arctic Butterfly for my brush. It contains a battery operated motor which rotates the brush head at high speed to produce enough centrifugal force to cause any dust in it to fly off, and build a strong static charge. You’ll pay more for this superior tool, but it’s worth it. The Arctic Butterfly also has a light to help you see while brushing the sensor clean.

This method will clean most of the stubborn dust, blowing alone won’t remove.
Tip: While laying your camera down during tool preparation, cover the camera’s lens opening with the camera cap which came with its purchase to keep dust out.
Cleaning the sensor with a non-film forming optical cleaning solution:

If blowing and brushing doesn’t work, you’ll need to clean the sensor using an optical cleaning solution.

The traditional technique is called the Copper Hill method, originally developed by Copper Hill Images. While some of the tools have evolved since Copper Hill developed the technique, it’s still basically the same.

To wet clean your sensor, I recommend two products from Photographic Solutions Inc. (PSI); Sensor Swab and Eclipse Optic Cleaning Fluid.
Tip: In the past, Pec*Pads were recommended by Copper Hill, however, the manufacturer of both Pec*Pads and Sensor Swabs, PSI, recommends only Sensor Swabs.
Sensor SwabSensor Swabs come in three sizes, matched for different size sensors. You’ll need to purchase the correct Sensor Swab for your camera.

Remove the lens, then lock up the mirror. Wet a Sensor Swab with 2 drops of Eclipse solution. Wait 5 or so seconds before beginning the cleaning. Too much Eclipse solution on the swab can leave a sensor film you’ll have to remove later.

With the camera facing up, use firm pressure, to wipe the wet swab in one direction across the sensor, then reverse wipe the sensor, carefully touching the sensor only with the soft end of the swab. Repeat the action until the entire sensor has been wiped. If the dust is especially stubborn, you may need to use more than one wet Sensor Swab.

Check to make sure your sensor is clean:

Many sensor cleaning procedures don’t seem to include a way to tell if the sensor is actually clean. Much of the sensor’s dust, which shows up in photos, isn’t visible to the naked eye on the sensor, even with excellent illumination.

Sensor LoupeI use the BriteVue Quasar Sensor Loupe to carefully examine my sensor periodically during the cleaning process, and to ensure it’s clean at the end. It’s a 7X magnifying glass with LEDs for illumination. Placed over the lens opening of your camera, it enables you to fully examine your DSLR’s sensor to determine its cleanliness.

Once the sensor is clean, release the mirror from its locked position and reattach your lens.


Harold said...

I've printed this one out Ned. Thanks.

Sam said...

Fantastic. This is the best explanation of how to clean my sensor that I've seen. I never heard of Visible Dust before. I've place my order with them. Thanks for the heads up about their products.

Janice said...

Super article as always. This is an important one to reference, so I've bookmarked it and printed it out.

George said...

Super article. I'll be using it today. I just picked up the swabs and eclipse at Calumet. Thanks.

Paul in Norther Ohio said...

Excellent advice and I just used it to clean my D300 sensor. It took a couple of tries to get it completely dust free. I discovered that it helps to blow out the chamber with the mirror down before moving on to the “mirror up” to clean the sensor. The first time I went directly to the sensor, got it clean and then took a couple of test shots. The first was great, the second and subsequent were dusty. I deduced that there must have been dust trapped by the mirror.

I’ve added this step to the beginning of the process:
Before locking the mirror up, use the blower to blow out the chamber. I hold the camera with the lens mount down to allow gravity to help and am very careful to not let any part of the blower touch the mirror or any part of the camera.

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