A subtle image artifact along the center of the frame, sometimes referred to as a “stitch line,” may be visible during rare combinations of scene lighting and lens selection. Although this has not been observed by most customers, RED has created a behind-the-lens mitigation if your specific shooting conditions are susceptible. If you would like this installed on your camera, or would like to discuss this topic further, please contact RED support.
In addition to this optional in-camera mitigation, RED has introduced an adjustment in REDCINE-X Version 61 (Windows / Mac) called “Automatic Mask Line Adjust” which can adjust out the visibility of this artifact should it occur on any of your footage. This adjustment does not require the installation of the behind-the-lens mitigation, but rather is a post-production solution to address footage that may be affected by this phenomenon.
Can you provide more details?
Yes, this image artifact may happen with certain types of stray light or flare within the camera’s sensor cavity. As a result, some combinations of strong, flare-inducing light and lens design may be more susceptible. Also note this is an optical phenomenon; the sensor is functioning as designed with unsurpassed image quality.
Are there any recommended best practices?
The recommendation for this and with image quality more generally, is to follow best practices with minimizing sources of stray light that pass into your camera. This includes using standard tools such as a lens hood or matte box, and when necessary, an RF to PL lens adapter that has proper flocking and unreflective internal surfaces.
Will the behind-the-lens option interfere with desired, intentional lens flares?
The behind the lens option only mitigates the flare generated within the sensor cavity; intentional lens flares from within the lens itself remain unaffected. With highly off-axis light, there is the possibility that a small shadow may appear at the edge of the frame. This shadow is caused by the newly installed guard stopping the light that would have otherwise reflected within the cavity.
When looking directly at the sensor I can see a line; is there a problem with my sensor?
No, when looking directly at this and other sensors without a lens attached, reflected light is different from what is actually recorded by the sensor; reflections such as rainbow patterns, lines, color shifts, sensor grid patterns, etc. may therefore be visible.
I exposed the sensor without a lens and see a line in my image; is my sensor faulty?
No, this is not a valid test because all cameras are only designed to operate with a lens attached.