Sometimes, there simply isn’t any way to get the image you want with a single frame.
Most often, this will occur when an image has a very high dynamic range (a mix of very light and very dark areas). Just about everyone has encountered that dilemma – a photo with a blown-out sky, or a nearly black foreground.
Another situation is an image where a polarizer filter works well for only part of an image. This can happen when you’re using a polarizer with a wide-angle lens, and shooting clear blue sky. A less-common situation is using a polarizer to “see through” water, while also increasing contrast in a sky. Each of these actions might require the polarizer to be twisted in different directions, so there’s just no way to do it in one shot.
Some blending is straightforward… when you can make a smooth transition from one image to another, it’s not too difficult to do. But, when you’re faced with irregular edges – especially trees that line the horizon, it’s gets very difficult.
In a nutshell; you can’t darken the sky without also darkening the trees. Often there isn’t much you can do… the trees will have moved slightly from frame to frame, and no matter how skilled you are, you’re going to get jagged ugly edges. But, sometimes, you can use a couple tricks to help out.
The following 3-part tutorial is about 15 minutes long, and covers a couple of these situations. In this tutorial, I’ve taken 3 images and assembled them into one.
The first part introduces the 3 images. Each of these images is a separate frame with a unique RAW file.
The second part is a straightforward blend using the gradient tool.
The third part is a more complex blend including an irregular edge of some distant trees.