The main effect of using a circular polarizer filter while capturing a rainbow can be seen in the following animation:
To generate this gif animation a circular polarizer filter was used. The filter was rotated stepwise to show the appearance and disappearance of the rainbow. This animation of the rainbow at Niagara Falls contains a total of 13 single exposures.
A polarizer filter can help to increase the saturation of the rainbow in an image, but it also can eliminate the polarized sun reflection in the image. Therefore, depending on the used focal length it might be necessary to capture several images with different polarizing filter settings to bring out the colors of the rainbow in the entire image.
The use of a tripod is highly recommended, but it is not mandatory thanks to post processing. The shown animation was captured hand-held while rotating the circular polarizer step by step.
This image of the Rainbow Bridge in Tokyois is based on 366 single exposures from a time laps capture of 1.5 hours.
The main idea behind this image is to illustrate a full 1.5h captured time lapse in one single image. In this example the final image contains 366 single exposures.
Start of sequence
End of sequence
To generate the above image the 366 exposures from the beginning of the time lapse (golden hour, left side) to the end of the time lapse (end of blue hour, right side) were averaged.
To calculate a smooth image with these 366 captures an own developed algorithm was used. This algorithm uses the image information of several images to generate a smart rendered result. The direct outcome of this algorithm can be seen here:
Result of the 366 smart averaged images
To generate the final static time lapse image (first picture) the city lights from the last captured image of the time lapse sequence were added. The Rainbow Bridge Time Lapse sequence is one of several time lapse of the YouTube Channel.