Hope someone can help me. I am trying to figure out how to get the subject distance when taking a photo with a P4P. I know there is a field called Subject Distance in the jpg file details, but it is always zero. Is there a way to turn this on in the P4P so that I can get an accurate subject distance, or another way to get an accurate distance? Thanks.
Subject Distance in jpg details
- Thread starter Mike Dasbach
- Start date
The short answer is no.
There is a field but DJI don't put anything into it.
With a proper detailed Exif viewer, it shows as Subject Distance: Unknown
It's the same for shots from my big Nikon SLR and shots from a Samsung phone don't even show the field.
What do you need the distance for?
Thanks for your reply Meta4. I had a chimney sweep ask me if there was a way to get measurements of a chimney with a drone for doing inspections, since some of the chimneys are quite high and on steep roofs. I started playing with it and if you know some of the parameters for the picture like the focal length, distance of the subject, and resolution, you can determine the size of a pixel and then measure the number of pixels to get the measurement. I was using the DJI Go app and the distance it gives on the screen from the collision avoidance system, but I don't think that is real accurate, since it will jump from 12 to 15 to 20 and back and forth. I saw the subject distance in the details of the file and thought if there was a way to turn it on, that would work great. I guess there isn't. Any other suggestions on how I might get a good distance for the calculations? Thanks.
BIGAL65
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Sounds like you’re getting into the realm of photogrammetry. You can make measurable 3D models with drones using programs like Pix4D (Recommended) and Drone Deploy.
If you’re looking for simply a way to measure the distance of an object from the drone you’ll need a payload like the Zenmuse H20 with its laser range finder.
If you’re looking for simply a way to measure the distance of an object from the drone you’ll need a payload like the Zenmuse H20 with its laser range finder.
