Filters on drones – this is a hot topic in the drone forums, and often clouded with misinformation. The use and effects of filters should be understood before adding additional glass to the front of your lens. In drone photography, we have a slightly different set of challenges than tripod-based photographers when it comes to filters.
During the film and chemical days, we used a variety of filters in front of our lens, behind the lens, in front of our studio lights, and in the darkroom enlarger. Common film camera filters included neutral density, UV/haze, red #25, yellow #12, soft focus, warming, and polarizers. Today’s post is about polarizing filters, or rather, how to achieve the desired effect of a polarized photo without actually placing using the filter on the front of your lens.
A polarizer filter is most often used to 1) darken hazy blue skies while maintaining puffy white clouds, 2) manage reflections from natural objects like tree leaves or artificial surfaces like a shiny vehicle windshield, or 3) reduce glare from the surface of lakes, streams, and the ocean to help clarify the water.
A polarizer filter will block out the messy light beams; those which are bouncing and reflecting in disorganized directions and creating glare. In a simplified analogy, the filter works similarly to the slats of Venetian blinds; the light coming in through the blinds is filtered in an organized direction.
Sure, you can add additional filtration to the front of your drone lens. Many polarizer filters are available now for DJI Phantoms and Mavics. There are drawbacks, however:
- A polarizer has to be aligned (rotated) properly to achieve the desired effect and this alignment is difficult to predict when you are standing on the ground just guessing the angle and direction at which you will be aiming your camera from the sky toward the subject.
- Polarization filters work only perpendicular to the sun.
- A filter adds weight to the front of your drone camera, upsetting the delicate balance of the brushless gimbal, and potentially giving you gimbal overload errors or gimbal failure.
- A filter is made of glass or plastic which was not engineered for your particular lens. Reflections, flare, and chromatic aberration may be introduced unintentionally. You will have a certain amount of reduction in image quality regardless of what filter you use.
This being stated, it is suggested that you weigh the benefits against the costs before applying filtration to your camera lens.
The great news is that we have methods to create a polarizing effect in post-processing. Let’s go there now! Adobe Lightroom has recently released a new version of Lightroom software (In fact, two new versions, creating some confusion among users.) Lightroom has become the standard software among professional photographers for post-processing and photo organization. For those who do not want to go too far in-depth with image editing, we also suggest Macphun Luminar for the many presets designed especially for drone photographers.
Let’s get down to creating a polarization effect in Adobe Lightroom. Step #1 is to identify your desired results. In the sample photograph, I was working for a fancy resort in the middle of the Pacific ocean. The purpose of the drone shoot was to sell more hotel rooms. I made the photo of the two models basking in the sun on their surfboards. I loved the image and wanted to communicate to the viewers that the water was warm, clear, tropical and alluring. In fact, the water is as stated, but I needed to make it look more like a swimming pool. This is fairly simple to do in Adobe Lightroom post-processing.
In Lightroom, the two key sliders for a polarized effect are Dehaze and Clarity. I like to use the Adjustment Brush to apply these effects to specific areas on the image. I use a huge, soft Adjustment Brush while being sure that the Auto Masking is checked on.This way it is possible to paint all the water quickly as long as the crosshairs of the brush don’t touch the surfboards. To check the accuracy of my auto mask, I hover over the black dot on the image, which indicated an adjustment tool had been used.
The final photo worked perfectly. I was able to communicate to the viewer that this resort destination has water so clear and warm as a swimming pool in Palm Springs in the summer. The client loved it! This was all accomplished without adding another piece of glass to the front of the high-quality Phantom 4 Pro or Mavic 2 Pro lenses.
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Authors Randy Jay Braun & Stacy Garlington are co-founders of the DJI Aerial Photo Academy, providing live city-to-city workshops helping attendees to create better drone photographs for work and for play. If you would like to attend, find the current workshop schedule at www.djiphotoacademy.com and on their facebook page. Please contact firstname.lastname@example.org with any questions.