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Neutral Density filters for photogrammetry mapping?

SandCop

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I've just started using my Evo 2 Pro for photogrammetry mapping missions. I've had some problems with hot spots when flying near solar noon (sometimes I can't control when I can fly). I was wondering if anyone is, or has, used ND or polarizing filters when photographing for photogrammetry processing. If so what were your results?
 

herein2021

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I've just started using my Evo 2 Pro for photogrammetry mapping missions. I've had some problems with hot spots when flying near solar noon (sometimes I can't control when I can fly). I was wondering if anyone is, or has, used ND or polarizing filters when photographing for photogrammetry processing. If so what were your results?

I don't understand what you think ND filters will do to improve the situation. In those scenarios you simply need to expose for the highlights by increasing the shutter speed or stopping down the aperture. You can read here why I never use ND filters with drone cameras and here on why I never use CPLs with drone cameras.

I personally have never tried photogrammetry but the camera concepts are the same regardless of what the final images are used for. If you are trying to completely automate the image capture process then you will need to use Aperture priority mode, F5.6, ISO 100, Daylight WB, no shutter speed limit, and hope for the best. An ND filter or CPL will in no way alter the outcome of your footage in a positive way let alone eliminate hot spots. All an ND filter will do is decrease your shutter speed but hot spots will not be affected or eliminated.
 

Brock Inspector

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A circular polarizer can indeed knock down specular highlights (reflections off water, vegetation and some other surfaces, though not all). There's another kind of hotspot that the Pro 6K camera is prone to, and that's lens flare from the sun entering the unshaded lens barrel if the camera is oriented within about 90 degrees of the sun... is that what you're referring to SandCop?
 

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