I took pictures at our RC club field last weekend to show everyone what 400ft. looked like. We had an FAA official there for a meeting. I stopped at 400ft. according to my ST-16. The picture properties only showed 225ft. I have pine trees West of my house that are about 100ft. tall and I took pictures even with the tops. The ST-16 showed 105ft. but the picture properties showed only 25ft. What could be the problem?