Can you tell me more about that? I've taken photos at all the parks I have visited.
It was a story that appeared here on FR within the last 3 months. People have reported being harassed by Rangers who told them photography was not allowed in Nat'l Parks. I don't recall many details beyond that. A search on FR would probably bring up more.
From what I read professional photographers would now need to pull a permit(I believe it was around $1500) prior to taking pictures in National Parks. If caught without the permit a fine would ensue. I am not sure if this applies to your general vacationer taking snapshots.
Here is a link.
http://www.oregonlive.com/environment/index.ssf/2014/09/forest_service_says_media_need.html
Commercial filming and photography on public land (Park Service, Forest Service, BLM, Army Corps of Engineers, etc...) has carried a fee for decades, and companies or individuals who sell their photographs or films without having a permit can be fined. Personal filming and photography is perfectly fine, allowed, and even encouraged in many places.
This all stemmed from an improperly interpreted story from a couple of months ago regarding the Forest Service stating it will charge news agencies fees for doing stories (whistle-blower type, anyway) on public land (filming and/or photography), and that the fee was higher than the fine (think the fee was $1,500 and the fine only $1,000), even though this would clearly be covered under the First Amendment and freedom of the Press. People were misinterpreting then, and they still are today.