Discover hidden depths

Change the depth of field after you’ve taken the photo

Depth of field is one of the main elements in photos that you can change to creative effect. We often want an entire landscape in focus, for example, but for portraits, we may prefer the creamy look that a wide aperture gives. Or perhaps we’d prefer the opposite! Then, maybe, we’d love to be able to decide after we’ve made the shot.

When the now-defunct Lytro Illium came out, there was great interest in seeing this practically. Lately, the idea has made a re-appearance via portrait modes on the latest smartphones Lightroom offers the ability to use the Depth Mask from iPhone HEIC files for editing. You can edit the foreground and background separately using this mask, including the level of blur.

For stills cameras, there isn’t a real option to do this in post without using Photoshop. You can still achieve a passing resemblance to a shallow depth of field inside Lightroom, however. For the best results, start with a photo that was shot with the whole scene in focus. It’ll also help if you have a focal point that can be enhanced with a shallower depth of field.

1 Apply lens blur

This technique uses an interesting feature of the

Sharpness slider in Lightroom’s

Local Adjustments. With negative sharpening, -1 to -50 on the slider removes sharpness from the photo, but from -51 to -100, it becomes a lens blur tool. This effect allows you to emulate opening up the lens aperture in Lightroom.

For this photo, we’re going to use the Graduated Filter. Reset the tool by double-clicking on the ‘Effect’ label. Now set the Sharpness slider to -100. You can adjust this to taste later, but for now, use the maximum negative value.

2 Add a grad

Next, drag the Graduated Filter down the image from about midway. You specifically want a reasonably long gap between the inner and the outer boundaries of the filter: a short gap would mean a quick jump from sharp areas to blurred ones. If you look at real-life photos with a shallow depth of field, you’ll see that the transition, while clear, generally isn’t abrupt.

For this reason, go longer with the Graduated Filter transition. You’ll notice that the church is blurred as well after you apply this grad; but for now, you should really just be looking at the effect on the surrounding landscape.

3 Restore the focus

In the Graduated Filter controls, switch the mode to Brush. Select the Erase Brush. Make sure Auto

Mask is on, and that Flow and

Density are at 100. Finally, press

O (the letter, not the number) to turn on the mask overlay.

The overlay is red by default, but you’re working on a red roof, so it’s best to change the colour. You can toggle colours by pressing Shift+O. Green is probably the best option here. Erase the mask from the church by first painting along the edges, and then from the centre. Don’t forget the cross on the spire.

4 Rough it up

The final step is to add a little blur to the foreground. Click New in the panel to start a new brush.

Assuming you made your settings before using the first Graduated

Filter, these should be the same as the first one. If not, double-click Effect to reset and set Sharpness to -100. Drag from the bottom, again with a long transition. You may need the filter to start outside the frame.

Finally, tweak the Sharpness to taste on both filters. Sharpness at -100 may be too blurry for you, so change them to see what you prefer. This can also help with haloes on edges.