Combine images to show and stop motion blur
Photographing a scene with ferns in the foreground and a waterfall in the background. Slight breeze causes ferns to move.
- Depth of field from the foreground to the background.
- Silky waterfall.
- Sharp foreground.
- Silky waterfall requires long shutter speed ( 1/4 second or longer).
- Moving ferns require a fast shutter speed (1/30, 1/60 or faster. This depends on the amount of movement.
- Take two separate photographs, one with silky waterfall (long exposure), one with sharp foreground (short exposure). Combine images in Photoshop.
In the field:
Tools: Nikon D300, Tokina 12-24mm f/4 lens at 13mm. Polarizer. Composition locked on a solid tripod and ball head.
First shot: Set up for normal for hyperfocal focusing of the scene. This ensures focus throughout, including the area near and just behind the foreground object.
Set exposure. In this case f/16 at 1.6 seconds at ISO 200. This is the shot for everything but the moving fern.
Second shot: Refocus on foreground element. Set a wide aperture (f/5 in this case) and adjust shutter to achieve same exposure value. If using Aperture priority the exposure value will automatically be the same. Initially, you may not be able to set the shutter at a fast enough speed. If this is the case, change the ISO until you can achieve the needed shutter speed. For this situation, the second shot was taken with a shutter speed of 1/30th second at f/5 using ISO 1250
At the computer:
- Import the images into Lightroom and make any adjustments needed. For the foreground image shot at ISO 1250 I used some noise reduction.
- Images were exported from Lightroom into Photoshop as layers. In Lightroom, select both images, right-click and choose Edit in > Open as Layers in Photoshop...
- Once in Photoshop, arrange the layers so that the background image (the silky waterfall) is the foreground image. This can be done by simply dragging it above the other layer in the Layers Palette.
- Make sure the foreground layer is selected and create a layer mask by clicking on the layer mask icon (the little circle in side the rectangle) in the Layers Palette.
- Click on the layer mask to make sure it's selected.
Set the Brush tool to black and start painting over the ferns in the image's foreground. By painting the layer mask black, whatever is on that layer is hidden and whatever is on the layer below is shown. In this case, the sharper ferns show.
When using a layer mask in this way you'll often need to reduce the opacity of the brush to work the edges of the mask to blend the foreground and background images. This takes some practice but the advantage of using a layer mask is that if you switch the brush to white, you can paint the layer back in. So if you make a mistake, switch to white, paint over the mistake and try again.
This is just one of several situation in which I've used this same technique to combine images for sharp foreground and background in spite of conditions that won't allow for it in one shot. The toughest part about this, for me, has been remembering that I have this option. Honestly, I'm sometimes still a little glued to the old slide film ways of doing things, even though I've been shooting digitally for 13 years.