Have you ever been to a popular tourist attraction and simply can’t get a photograph devoid of people? How about you want to get one of those cool landscape shots where you make the ocean waves turn into a cloud of mist, even when it’s high noon and sunny?
The most obvious answer for most photographers trying shots like these is to use a really strong neutral density filter. What happens when you only brought along your lens with the 105 mm diameter filter thread and you never got around to buying that $400 filter (they really can cost this much)? How about you at least remembered to bring your tripod, but forgot your arsenal of filters? How about you brought that cool super-wide lens that doesn’t even let you mount a filter?
There’s still a way to get that image you crave. You don’t even have to sacrifice using your sharpest aperture or be forced to put a filter over a long lens that has its resolution ruined by filters.
The solution to this conundrum is to use image stacking. For me, I turn to the same “CombineZM” free program that I use for focus-stacking my macro shots. (There’s also a version called “CombineZP”) Yes, you probably need a tripod, and yes, you need to take several shots of the same scene. You can download this program from a variety of sources, such as here.
The technique is pretty simple. First, take several shots of the scene without moving the camera. To get rid of that crowd, take a series of shots where people aren’t standing in the same place for each shot. Don’t use auto-focus or change exposure between shots.
⦁ Process your shots into a format such as TIF or JPG (CombineZM doesn’t like raw format).
⦁ In CombineZM, select File | *New
⦁ Browse to your series of pictures and select which ones you want to combine (hold shift key to select a range). The pictures should all be in the same folder.
⦁ Select Stack | Replace Groups, Average
The CombineZM program expects your exposure to be correct in each frame for this selected stacking option. It will “merge” all the selected photos into one shot, and will also reduce any image noise that might be present. In fact, some people use this technique purely for the noise-reduction feature, primarily for the shadows.
For the best results, I’d recommend that you use at least 10 shots. If you use 10 pictures, then a person appearing in one of those shots will only contribute 1/10 to the final picture (90% transparent).
5-shot “average” stack. Still looks a bit ghosty.
If a ghost-like shot is what you’re after, that is of course completely possible. You also might want to get a model to stand still while everyone else is moving around, leaving the model standing all alone. It’s all about getting creative, isn’t it?