That's the way it works. You will have about a one second gap in your video each time you take a still photo.

They learned that from Nikon with the 800E.

The filter is not just removed; that would change the thickness of the sensor stack. You are paying for a new, thinner, low by pass filter mated to a cancelling filter so the stack remains at the correct thickness.

If you do most of your shooting in a studio this is something for you to consider. If you are wanting an all around camera, I would wait for the 5dm4.

This!! Any camera with with live view has the necessary hardware to do video. It appears that Nikon charges extra to not be able to save that video using the Df.

Yes.

This is the reason you rarely get a sharp still from a video. Video is capturing motion. Because of the shutter speeds used even a single frame will have motion in the frame. That's okay for the video but not for sharp still pictures.

You are correct. These new high capacity cards are designed for capturing 4K (and higher) video. It doesn't take long to fill up the space.

I thought it was interesting how they would go inverted to keep positive G's on the plane when crossing ridge lines.

Both the 1DX and 5DM3 are older than the aging 6D.

Since I know nothing about Nikon I will defer to you. I was just throwing a suggestion out there. Shows the difference in how different companies approach things. Remotes used with my Canon don't time out.

On most remotes, the button functions as the camera's shutter button. If you have moved the focus from the shutter button to a back button and have focus priority set, the camera will not take a picture. Try putting focus back on the shutter button and see what happens.

This link says that Canon and Nikon may do just what this thread has been talking about. You should probably read it.

This reinforces the primary rule of buying a tripod - of the three things to consider when buying a tripod

light weight
stability
low cost

you only get to pick two.

I thought it was 85.177%.

In my understanding of reading many posts on this, the 5ds comes with a normal, fully functioning, low-pass filter. The 5dsr comes with the same filter in place but the results some how (R) reduced or (R) removed. You have to choose which you want; neither one does both. It seems the 5ds is designed to be the studio camera, where clothing and props may create moire and aliasing, and the 5dsr is the landscape camera where the low-pass filter may not be as important.

The question is ask 'why don't they just take the filter out?' The camera companies are selling systems, were all the components are designed to work together. Taking the filter out changes the thickness of the sensor stack, so it is easier to leave it in and change the effect. See this link to start your research on the sensor stack.

http://www.lensrentals.com/blog/2015/01/a-thinner-sensor-stack