During my last road trip, I captured thousands of images. The majority of those pictures involved taking more than one exposure and blending them in Photoshop to solve some challenge--greater dynamic range of light, greater depth of field of focus, selective polarization, erasing tourists, etc.
One of the most interesting sites that I came across during my trip was Salvation Mountain. Salvation Mountain is a very colorful place near Niland, California. It's basically in the middle of nowhere! For this photograph, I selected a wide angle focal length (29mm) and positioned the lens very close to the mailbox. Since the mailbox is so close (maybe a foot away) and the mountain so far from the lens, it's not possible to have render both of those things as tack sharp with one exposure. The solution is take take two or more exposures.
First, I took an exposure with the lens focused on the print on the mailbox. Then, I took a second exposure with the lens focused on the print on the mountain. In Photoshop, I opened both images and stacked the file with the background in focus on top of the picture with the mailbox in focus. Once the pictures are layered, I made sure to align them. With both layers selected, go to Edit >> Auto Align Layers >> Auto.
I applied a mask to the top layer--the one with the background in focus. Within the mask, I painted with black over the mailbox and surrounding foreground. Remember that white reveals and black conceals. So, by painting with black, I concealed the background focus--leaving the bottom layer to render the mailbox in focus. The end result is that the entire frame is in sharp focus.
Here's the final image: