Photography is such a fun in most cases, but there are some annoying things about it, and one of them is the lens dust. It doesn’t matter how often we clean our gear, it’s almost impossible to avoid dust spots on our images. They can sadly break our pictures, even the most amazing ones. Moreover, one of the most common rejection reasons on aviation photography websites is dust and dirt. However, we can easily remove them with image editing software, like Photoshop or Lightroom, etc. Let’s find out more about this frustrating issue!
What is a dust spot?
We can find dust everywhere, even if it is invisible. It lands on the camera body, on the lens. Dust spot is a small mark on the image we’ve taken.
Each time when zooming in and out, or focusing with our lens, dust may get inside the camera by the movements. Furthermore, if we have more than one lenses and change them quite often, there is a possibility to find some dust inside the camera body. The unwanted dust gets inside when we change our lenses, – even if we are really careful – and sticks to the mirror, lens exterior or to the sensor.
It’s obvious that we need to change lenses, as none of us can afford to buy as many camera bodies as lenses we have.
The best way is to protect our equipment from dust, to hold them towards the ground when switching lenses. In that case, dust can’t get into the sensor.
How do I know if my DSLR sensor is dirty?
The easiest way to find sensor dust is by running a test shot with the camera. Before anything else, choose a wide-angle lens for the initial check, as sensor dust is most noticeable on short focal lengths. (In case of any vignetting issues, pick a different lens with longer focal length.) Then follow the steps below:
- Turn on the camera.
- Set it to Aperture Priority Mode.
- Choose the lowest ISO value (ISO 100). Switch off auto ISO!
- Turn autofocus off, set the camera to manual focus (and lens too if possible).
- Set aperture value to the largest number available for the lens, somewhere around f/16-f/22.
- Set metering mode to Matrix / Evaluative metering.
- At outside, point the camera to the blue sky, if indoors find a clean paper or white wall.
- Fill the frame, make sure that the lens is entirely out of focus and take a shot.
- By zooming in the image dust spots become visible if there’s any.
How to find them on our images?
Sometimes it’s pretty easy to find dust spots on the image, but in certain cases, they can be invisible for our naked eyes. It’s good to know that most dust elements are only visible on smaller apertures, like f/5.6 or even higher. The size and visibility of dust particles are changing as we adjust the focal length. By increasing the aperture, the dust becomes smaller and darker.
There are several ways to recognize them with an image editing software like Photoshop, by applying levels, gradient map, curves, increasing contrast, etc. I personally use the Equalize command to find them on the images. When applying this adjustment, the program finds the darkest and lightest areas in the picture and reallocates them. Therefore, the brightest area stands for white and the darkest one for black. Any dust spots should appear now on the image. If we can’t see any, it means our picture is clean.
How to remove dust spots from the photograph?
- First, I open up the image in Photoshop.
- Then I create a duplicate layer.
- On the new layer I apply the Equalize command, by Image > Adjustments > Equalize
- Then I select the original layer (background layer) to remove dust spots from the image.
- Afterwards I choose the spot healing brush tool to remove dust spots from the picture. Also, make sure that brush type is content-aware and sample all layers have been selected too.
- Adjust the brush size accordingly, then click on the spots.
- When all done, I remove the new layer (background copy).
- Finally, I double-check the image if it’s free of dust spots by moving it from side to side on the screen. If still dirty, then repeat the process again till it’s all cleaned up.
How to clean the camera from dust?
Now we should understand why is it really important to keep our equipment as clean as possible. Once dust gets into the camera, it’s difficult to get rid of it. There are a few options what we can probably do to clean our sensor from dust:
- Most of the cameras have built-in self-cleaning modes, so it’s probably one of the options to clean the sensor. For more information read the camera’s manual.
- On the other hand, we can use a rocket blower to eliminate bigger dust pieces.
- Alternatively, we can apply sensor swabs if we are brave enough!
- Seek professional help at local camera stores, where they clean the camera.
In conclusion, I would say, if we have to change lenses, then try to do it very quickly, or in a dust-free environment – if possible – for prevention. Also, remember to keep the camera body and lens towards the ground when switching lenses! By following these simple tips, we can avoid the frustration that dust can cause and save some precious time with post-processing too. After all, I hope this article helps to reduce rejections on aviation photography websites in the future for all of us. It’s all done and dusted then! 😊