Combine 3 or more exposures into 1

Remove moving objects using Photoshop's Smart Objects

Use the Stack Mode Mean

Keep moving objects using Photoshop's Smart Objects

Use the Stack Mode Minimum

It’s a perfect shot! If only those unwanted objects (cars, birds, people, etc) in the scene would disappear. As long as the unwanted elements in your frame move, even just a little, you can make them disappear from your image, by taking two or more shots and using Photoshop’s layering and blending capabilities.

You don’t have to retouch your image. Blending is different than retouching. The unwanted elements aren’t covered over with new information, by hiding them with replacement information similar to the surround, either from the same source or another. With blends, the information behind the moving subject is revealed. How? It’s contained in the other shot(s).
You can even do this with exposures that are made with slightly different angles of rotation or framing, so you can use this technique with handheld exposures, not just those made with a tripod. Camera motion may make manual registration difficult, but Photoshop will automatically align and in some cases distort the separate exposures so that they register precisely. In some of these cases, you may need to crop the final result to restore a rectangular frame.

You can even remove stationary objects with blends – if you move. In situations where there is sufficient parallax between foreground and background elements, by varying your angle of view, you can cause significant shifts in position of foreground elements without causing significant changes in position of background elements. Make multiple exposures from multiple angles of view and you can blend out the elements that appear to move. When using this technique, shoot loose, planning to crop more after the merger.

If you have only two exposures you’ll need to manually mask the top layer. If you have three or more layers Photoshop will automatically blend the layers.

So how do you do this with Photoshop?