Layering question?

I have an idea for a shot I would like to try but could use some clarification on layering. The image would ultimately be an action shot composed of two different exposures. One would be shot at a very low shutter speed. This one would be the background. The second shot would be at a faster shutter speed in order to freeze the action. If all I want from the second shot is the frozen action how would I go about layering them and taking only that part? Some careful cropping/erasing? Searched for tutorials but couldnt find any. Seems like it should be fairly straightforward but Im having trouble thinking it through. Thanks for any help.

What kind of editing software are you using?

- Joe U.

Would be in photoshop.

Keep the lighting in mind when making your original images. One thing that really gives away a composite image is lighting that looks unnatural. If you're shooting your action subject in side light, make sure your shooting your background subject in the same light. Of course if it's going to be blurred do to a long shutterspeed, the lighting may not be that noticeable.

It almost sounds like you are trying to get a panning look to your image. If that's the case, it can be done in camera, but it will take some practice.

Another option is to freeze the subject on the background you want, and use photoshop to blur the background.

Do you have Photoshop Elements or the full version? I use masked layers in Photoshop all the time. You'd create your two layers and then go to Layer > Layer Mask to create a mask. Then you can edit the mask in the Channels pallete.

If you have Elements, you'd do the same thing but you'd have to actually erase the layer with the cyclist (I'm betting this is a mountain bike photo) as needed.

From your description, I think you couls actually get the shot with an off-camera flash. Flash acts as a second, separate exposure. You can expose for your background and then use a flash to freeze a moving subject.

Mike- Definitely keeping lighting in mind. They would be shot from the same angle with a tripod one after the other so the lighting hopefully wouldnt change much between the two exposures.

Ha good call there John. It is mtn bike related. Thats a damn good idea with off camera flash. Think that might be the easiest way to go about it too.

Thanks for the help. Will post it up once I take it. Might be a week or two since the rider I usually shoot with just left town.