Creating Differential Focus in Photoshop

Differential Focus is all about keeping a small area in your photographs in focus and allowing the background details to blur or vice-versa. Differential focus allows the main subject to be more obvious in the picture. Creating a differential focus is essential to field photographers and wedding photographers. Differential focus may be created using lenses or by using the popular photo editor Adobe Photoshop.

The following is a guide on using the Adobe Photoshop to create a differential focus.

Step 1: Start Adobe Photoshop and Select File to Edit

You will start the Adobe Photoshop software by activating the program icon or an application shortcut and then use the “File” menu to select the “Open” option. Use the following file browser to locate a suitable file to carry out the editing operations necessary to create a differential focus.

Step 2: Subject Selection

You will go to the Tool palette and select the ‘Edit in Quick Mask Mode’ option and then make sure that the background color is set to black for the image and layers. You will proceed to select a hard brush from the menu on the left side and mark out the outline of the subject in the image. This will serve to mask (or cover) the selected area in a different color.

You can undo a mistake by simply exchanging the foreground and background colors (simply press the “X” key as a shortcut) and painting over the area where the mistake was committed. Once done with the outline selection, you will check the outline for any errors and clean up if an error is found. Next, you will paint the insides of the subject using a bigger brush.

Step 3: Editing

You will now select the 'Edit in Standard Mode' button from the Tool palette and will notice that the selection changes from color to blinking. The subject has now been masked out.

Select Filter > Blur > Lens Blur and configure the radius slider to the limit where there is a marked distinction between the background and the subject. Click “OK”. You will now do a “deselect” to clear any active selections. You may also use the quick mask mode to clear out any selections.

Alternatively, you can simply add a layer to your photograph and make that layer a “Blur Layer”. Make sure that you keep the original layer. Follow this action by adding a layer mask. You will then use the default color filter by hitting the “D” key to apply it to the blur layer. This will make everything that is blacked out, visible on the new layer. You will then select the brush and hit the exchange key (X) and use the paint brush around the subject with about 50% opacity. Make sure that you avoid hitting items that are not on the same plane as the subject. This will paint the background to a blur and make the subject stand out. Once satisfied, hit ‘Save’ and exit.