Do ghost reflections and vertical noise mean my polarizer is damaged?
Asked 11/22/2011
3 views
2 answers
0
I dropped my circular polarizer and later noticed a very light scratch after close inspection. Since then, I’ve seen faint colored “ghost” reflections near bright Christmas lights, and some vertical-looking grain/noise in darker areas of my photos.
Camera/lens: Sony SLT-A35 with a 55mm lens and a Kenko polarizer.
What I’m seeing:
- The ghost reflections appear near the bright lights on the tree.
- Rotating the polarizer changes their intensity, but they never fully disappear in that framing.
- If I remove the polarizer, the ghost reflections disappear.
- In some other, brighter shots, I don’t notice any issue.
- I also see vertical-looking grain in darker areas and I’m not sure if that is filter damage or normal image noise.
Does this mean the polarizer is ruined, or are these normal reflections/noise I’d expect when shooting bright lights at night?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
14y ago
2 Answers
5
1) extra images are just reflections from the polarizer. How can you tell? When you rotate it, they don't move. Therefore the angle doesn't matter, nor does the scratch matter. When you remove it, they go away. Therefore it must be causing it, but it is not related to the scratch or the angle being polarized.
2) The noise is just electronic noise. The higher you go in ISO the worse the noise gets. You can use noise reduction in post processing to remove it, but this has a price, you'll also loose fine detail and the image can start looking plasticky. You shot at 1600 ISO. Don't do that unless there isn't any other way to get the shot. Try again at ISO 100. Yeah, the shutter speed won't be 1/13, it will be much longer, so use a tripod.
Originally by user7310. Source · Licensed CC BY-SA 4.0
user7310
14y ago
0
Generated from our catalog & community — verify before relying on it.
Probably not ruined. The “ghost colors” are most likely internal reflections/flare caused by the polarizer, not the light scratch itself. A clue is that they disappear when the filter is removed, but rotating the polarizer only changes their strength rather than making them move away. With bright point light sources at night, light can reflect between the filter and lens elements (or even from the sensor/lens system), creating faint reversed ghost images.
The vertical grain is most likely normal electronic image noise, especially in dark areas at high ISO. If you shot around ISO 1600, that would explain it. Lower ISO will reduce it, but you’ll need a slower shutter speed, so use a tripod if possible.
What to do:
- Test the polarizer in daylight and in less contrasty scenes.
- Compare the same shot with and without the filter.
- For night scenes with bright lights, try shooting without the polarizer.
- Use lower ISO and a tripod to reduce noise.
So: the filter may still be usable, but it can cause reflections in this kind of scene.
Recommended products
UniqueBot
AI14y ago
Your Answer
Related Questions
What causes these reflections in my photos, and can a lens hood prevent them?
What causes a regular grid pattern in dark areas on a Canon 10D image?
Why do bright white spots appear on my IP camera at night?
How can I prevent or remove hot pixels in long night exposures on a Canon T3i/600D?
Why is there a dark spot near the center of photos from my Panasonic compact camera?