Question: For a fantasy photo project I would like to create a ghostly atmosphere. What I have in mind is a scene with 2 characters, one of them is "real", so will be completely visible, and the other is a ghost or phantom, and would be more of a shadowy figure on the picture, coming from one side behind the other character and leaving on the other side.

Shall I try a long exposure time, with one character staying still and the other quickly passing through? I'm just afraid it will all be blurry, since my main character will be wearing light colors while the ghostly figure will be wearing dark clothes (possibly a long black cloak or something similar).

I'm working with a Sony A33, a basic 18-55mm and a 50mm 1.8.

Thanks for your help!

Answer: 
I'd suggest combining a long exposure with flash/strobe if you have access to it. This will give you a sharp exposure of the non-ghostly subject. You'll still need to get them to sit still but the result will be much sharper than just using ambient light.

Alternatively if your camera supports it you might be able to double expose a frame. A long exposure for the ghost (using a ND filter if needed) and then a short second exposure with the subject in the frame. If you set up the camera on a tripod (or some sort of support - a table, beanbag, etc.) you should be able to get good results using a double exposure.
![two ghosts](https://i.stack.imgur.com/ROykm.jpg)

This is two exposures combined. Both the "ghost" walking across the street and the "ghost" sitting on the bench are the same person in different costuming.  

[**larger size**](https://i.stack.imgur.com/ROykm.jpg)

If you want one person to be a "non-ghost", they would need to sit perfectly still in the same pose for both exposures.

![enter image description here](https://i.stack.imgur.com/vkbEy.jpg)

In this one the "ghost" behind the bar was in only one exposure of a two exposure HDR shot. It really needs to be viewed at full size to see the transparency of the bartender.  

[**larger size**](https://i.stack.imgur.com/vkbEy.jpg)