Montag, 27. Oktober 2014

Color flicker in timelapse with Sony cameras (RX100, alpha 6000)

I recently discovered a weird behavior of my Sony cameras in timelapse operation. Although shooting completely manual (whitebalance, aperture, exposure, ISO, RAW) the images show a color flickering with some frames showing a magenta or greenish coloring.

Below you find an example of the RX100:

This is an example of the alpha 6000 with a manual lense (Samyang 8mm 2.8). The sky is ok but the grass has a greenish touch in the upper image and a red, orange, magenta touch in the image below:

The images are underexposed and exposure is afterwards increased in Lightroom. This reveals the coloring as shown in the images. Lighting should not have changed inbetween the photos, the interval should be in a range of a second.

I observed this flickering with my Sony RX100 and also with my Sony Alpha 6000 with the kit lens. I also thought that this is maybe a lens issue (for example stabilization or imprecise aperture) and I changed the lense on my Alpha 6000 to a completely manual lense without success. The issue is still visible and again only in underexposed images where the exposure is ramped up in post. An interesting fact is that in some of the images showing color flicker, the flickering takes place when the exposure changes in a very small portion of the image. In the above example (lower image) there is a car light visible at the right corner above the trees. In some further images of this series I observed a similar thing: If there is a small light point, the overall color changes. This issue is also very distracting in timelapses of stars for example if you have small changing light pollution this causes the sky to flicker in psychedelic colors. It also has to be noted that all the observations have been made outdoors so flickering by any frequency of an artificial light can be excluded.

I still have no solution other than making no underexposed timelapses with adjusting the exposure in postprocessing.

A similar observation was made with the GH3 but with no solution:

Further things which could be possible and need more investigations:

- Problems with the RAW compression?
- Light reflections inside the lense?
- Does it also happen with JPG?
- Do the electronics of the sensor / camera react to electromagnetic perturbations? Shielding?