You see them everywhere: on the window, on your desk, and maybe even on your favourite coffee mug. You may never think twice about them but when it comes to photography, you’d better care a lot more about these spots.
Spots, or sensor dust, or whatever you want to call it, are notorious little fellas that wreak havoc on your editing workflow. They may be easy to get rid of but when they attack your photos by the tens and hundreds, you’re often left defeated…not to mention left with unusable photos.
Where do these spots/sensor dust come from?
Spots or sensor dust are small dust particles that are on your digital camera sensor. But how do they get there you ask? Dust particles can travel to your digital camera sensor in one of many ways—but most commonly by way of changing lenses. When you change lenses on a dSLR, you are exposing your camera’s mirror and sensor behind this mirror, to the natural environment. You may not see the small particles floating in the air travel from point A to point B, but they are there all over the place and will eventually get in behind the mirror and on to the sensor.
Here’s just some of many ways in which dust can travel to your sensor:
- Leave the lens off for an extended period of time, exposing the inside of your camera to the environment.
- You change lenses in a windy environment, or in an unprotected area.
- You place your camera with the opening facing upward, allowing dust particles to easily make their way down inside your camera.
- When zooming your telephoto lenses in and out, this “breathing” motion can push dust particles inside.
What do these spots do?
As these dust particles rest on your sensor, they will be imaged on to every single picture you take. Some may be visibly large on your photos, often seen as a dark spot. Furthermore, they will appear in the exact same spot in each of your photos since they do not typically move on the sensor. If they happen to be in solid coloured areas of your photo, then it’s much easier to remove in Adobe Lightroom or Adobe Photoshop, but when they conveniently appear in an area with lots of detail, then this may affect your workflow quite a bit.
How do you get rid of these spots?
If you only have a few of them on your photo, then you can easily clone them out in Lightroom or Photoshop using the clone stamp tool, or the healing brush tool. If they happen to be in an area with lots of detail, you will need to carefully fix this within Photoshop.
Dust spots often just make a small portion of your image darker. If fixing the details is not an option (although this is the best option), you can try and lighten the darkened area using curves or levels and masking tools, to blend them with the surroundings. This is not an ideal solution, but still can be done in certain scenarios.
Can I see these spots in my viewfinder?
Dust particles that are on your sensor cannot be seen on the viewfinder. However, dust particles that may be on the mirror of your dSLR may be visible in the viewfinder. These particles do not affect the image itself though, since the mirror moves out of the way of the sensor when you press the shutter button.
Dust on the lens element
It is entirely possible that you have dust particles on the front and/or back of your lens element. In either case, you may see these in the viewfinder as well, and they will appear as dark spots on your image as well.
Why do the dots look slightly different from each other?
Some sensor dust may look slightly darker and some may look more defined than others. This all depends on what your aperture was set to. Generally speaking the smaller your aperture (larger f-number), the darker and more defined your sensor dust will appear in your image. Dust particles on your lens element may yield much larger darker areas in your photos than a dust particle on your sensor.
I see spots too! So now what?
If these spots are driving you up the wall, you will need to clean the sensor in your digital camera. While some may not mind this task, others may shy away from doing anything inside their cameras, which is completely understandable.
I would only recommend you clean the sensor yourself if you know what you are doing!
Otherwise, take your camera to an authorized camera store or your manufacturer’s head office to get the sensor cleaned (provided they do sensor cleaning for the public). Most manufacturer’s head offices will have a customer service desk, and may charge a small fee for sensor cleaning.
If you’re ok with having to clean the spots in Lightroom or Photoshop, then you can continue to do that. But keep in mind that it can get very time consuming and tedious if you find a lot of sensor dust on your image.
I have had instances where there were so many small dust particles on the sensor that there were just way too many spots on my image to clean. It pretty much made the image(s) unusable.
My sensor is now clean, how do I keep it clean?
Keeping your sensor clean means always being conscious of what it is being exposed to. Here are some tips to keep in mind:
- When you change lenses on your camera, be sure to turn off the camera first to eliminate any electrical currents from attracting dust.
- When removing your lens, do so in an appropriate environment. ie. not windy, dusty, or rainy. If you’re out in the open then change lenses in as sheltered area as possible, even if this is inside your camera bag.
- When removing your lens, face your camera down so the opening is faced towards the ground. This prevents dust from falling down into your camera. Attach your lens in the same way.
- If possible, don’t keep standing and change lenses as you risk dropping your lens on to the ground. I learned this the hard way! If you have a camera bag, place it on the ground, and put your camera in the bag and change lenses inside the bag.
- Always use your lens hood to protect the lens on your camera and put the lens cap and rear lens cap on the lens you’re not using.
I have a mirrorless camera, does this mean I don’t get spots?
No, you are still immune to sensor dust as your mirrorless camera still has a sensor inside.
In fact, since mirrorless cameras doesn’t have a mirror in front of it, there is a greater chance of getting dust on the sensor. You should be extra careful when you change lenses.
I have a sensor cleaning mode in my camera. Does this work?
This function on your camera is intended to do just this—to remove any sensor dust. However, it can only do so much. By introducing tiny vibrations or shaking the sensor, it attempts to remove sensor dust off the sensor and onto a catch/trap at the bottom of your camera. There is no guarantee all dust will fall off from this method though. Moreover, the dust catch/trap will eventually need to be cleaned if too much dust is collected.
What about an air blower?
If you have a manual air blower like the air blower that I have, I highly recommend using this first to remove any dust particles from your sensor. This is the first method that I use when I need to clean my sensor as it often helps to remove a large majority of the dust that I get on my sensor—and I get a lot!
Here’s what I do whenever I use the manual blower.
- Face the camera down so you are looking at the back of the camera.
- Lift the mirror through your camera’s menu.
- Squeeze the air blower away from the sensor a few times to remove any dust on/in the blower itself.
- With the blower about 3-4cm away from the sensor, use the blower to blow air into the sensor to remove any dust particles. Be careful not to touch the sensor or the mirror with the tip of the blower.
- If you see dust on the sensor, you can target the dust particles too.
- Try to do this relatively quickly as you don’t want to expose the sensor to the environment for too long. If you have the mirror lifted for too long, the camera may automatically shut it back down to conserve battery power.
Never use a compressed air canister, as you have the potential of blowing chemicals directly on to the sensor.
If you have any additional tips or techniques to remove sensor dust from your images, or have stories of your own, please feel free to share them in the comments below!