Boost your bokeh
Bokeh phone photography has proven to be a lasting success. In its early days, many thought it would go with 3D television – quickly fade into the shadows because it never felt really good.
It is now an essential part of any phone photographer’s arsenal and helps to give a person a fantastic portrait.
However, even the superior background blur modes in phones aren’t foolproof. Here are the tips on how to get the most out of your phone’s shallow depth of field images.
Keep your distance
Most background blur modes recommend a distance of around 1.5 meters between you and the subject. And few work very close, in part because the difference between the view of the two rear cameras then becomes too large (although some phones manage it with only one sensor).
Some phones will outright refuse to switch to bokeh mode if the object you’re pointing at is too close. The best policy is to actively know your phone’s camera and figure out what type of distance is best for your subject.
The iPhone X and XS also feature bokeh mode on the front camera.
The gap between foreground and background
The most important tip of the lot is to make sure there is a big gap between the foreground and the background. This makes the software less work.
Problems with blurring algorithms are often due to the question of whether the foreground becomes the background. By taking scenes where there is a clear demarcation between the two, you are much more likely to get sharp results more faithful to what a DSLR with a wide aperture lens would produce.
If you can, place at least 2 meters between your subject and surrounding objects.
Keep the contours of objects simple
Bokeh modes have improved dramatically since they became somewhat popular on smartphones in 2014. However, complex outlines will still make the best sensors in modern smartphones forgetful.
The types of patterns you want to avoid are those that mix small parts of the background with the foreground. Frizzy or messy hair, angled beard strokes, and other complicated textures like these make it very difficult to create a sharp line between out of focus areas and out of focus areas.
A bokeh photo taken on the iPhone XS. Credit: Apple
Avoid too many reflective and translucent objects
Transparent, translucent, and reflective objects can also cause bokeh issues. The classic example is someone wearing glasses with their face away from the camera.
If you are using a large sensor, large aperture lens, the image seen through the lens of the glasses will also be blurry. The phone’s bokeh modes tend not to add blur to these elements. While the final image still looks good if the rim of the eyeglass frames is kept, it’s a gift that was taken with software enhancements, without using traditional optical effects.
Given what you’re trying to avoid, it makes sense to review your snaps after shooting to make sure nothing is wrong.
Adjust the aperture before or after filming
Many phone bokeh modes let you simulate different camera lens apertures, measured by their f / stop value. When you change the aperture of a conventional camera, the “hole” that lets light through becomes larger as the nominal number of f / stops decreases.
Huawei’s background blur modes let you go from f / 0.95, for very pronounced blur, to f / 16, a setting that doesn’t add any additional blur. Some Samsung phones have a variable aperture with a physical iris which also changes the size of the hole.
You can change the virtual aperture when you take a photo or after viewing the image in the phone gallery.
The Samsung Galaxy S9 has a variable aperture lens
You still need to focus
Customizable aperture after shooting also means you can re-choose your focal point after shooting. However, don’t lean on it too much.
When a phone re-scrambles an image after taking the shot, it just applies a very smart software filter to an image with an associated depth map. There is always a conventional photo in its center.
This means that you should always be careful about selecting your focus point when shooting, especially if your subject is relatively close-up. Bokeh modes can use additional images, but do not combine usually not a whole series of images taken within the focus range of the phone.
If the background has a slight blur due to the natural depth of field of the camera lens, you cannot render it suddenly afterwards. However, there is one area of photography that does just that. This is called bright field photography, seen in Lytro cameras.
Look for the right sources of light
It’s easy to think of bokeh modes as simple blur filters, but the process of blurring goes far beyond just finding the parts to blur. The best bokeh modes also mimic some of the specific blur effects of large aperture optical lenses.
Shoot with narrow springs in the background, maybe garlands, and these flourish. They become distinct circles of light, not just blurry spots.
Recording a scene with a background made up of these tiny light sources is one of the best ways to achieve a true DSLR look.
If you don’t have bokeh mode, get as close as possible
So far we’ve been talking about phones with built-in bokeh modes. But what can you do if your phone doesn’t have one?
You can achieve a degree of background blur by using the natural depth of field of the actual camera lens. Since we are dealing with a phone with a very small lens and a small sensor, you will only notice this natural bokeh if you get very close to your subject.
It’s great for macro photos, but it’s not very useful for portraits. Stand back enough so that someone’s face matches the lens blur.
Isn’t that good enough? You can also try to simulate the effect with filters. Google’s Snapseed app has circular and linear blur filters that let you try to roughly outline outlines with blurry objects. It’s a much less polished approach than soft focus, but it helps create bold or artistic images.