How to control the F Stop on your iPhone and take perfect photos every time

Have you ever seen those awesome photos that have a blurry background? It’s a very popular effect in the photography community, and it has long been associated with expensive cameras with specialized lenses. iPhones can recreate this effect using multiple cameras and machine learning to determine distance. The feature is baked into Portrait mode, and you can control the level of blurriness by changing the F Stop setting. Let’s show you how it’s done!

Editor’s note: We used an Apple iPhone 12 Mini running iOS 17.3 to formulate instructions within this post. Remember that some things may look different depending on your device and software version.

What is F Stop, and how does it affect photo quality?

In traditional cameras, a narrow depth of field creates this “blurry background” effect. The depth of field refers to the area in focus, in relation to the distance between the camera and the subject. This parameter is determined by four factors: aperture, sensor size, focal length, and the subject’s distance from the camera. The main factor is usually the aperture of the lens, though. A wider lens aperture will narrow down the depth of field, blurring out more of the foreground and background, hence creating a better bokeh. This is where the term F Stop comes from.

In camera lenses, the aperture is measured in F Stops. These are measured using a ratio of the focal length divided by the opening size. A smaller F stop number will signify a wider aperture, which in turn results in a narrower depth of field or more blur. For example, an F/1.8 aperture will blur the background more than an F/3.5 aperture.

In the case of the iPhone, the cameras and software determine how far everything is in the picture. If you tell it to recreate bokeh with a wider F Stop, it will artificially blur out anything outside the area that should be in focus. Because modern smartphone cameras are getting so good at determining all factors, results can be pretty good.

How to control F Stop on iPhones

As with anything on iPhones, controlling the F Stop on iPhones is very simple. You just have to know where to look. Let’s show you how it’s done.

1. Open the Camera app.
2. Go into Portrait.
3. You’ll see an icon in the top-right corner with an F. Select it.
4. A new slider will show up by the shutter button. Slide it left or right to control the “depth.”
5. Make your selection and take a picture.

Changing the F Stop after shooting an image

The great part about doing this artificially is that it’s technically a glorified edit. iPhones make it possible to add or remove blur after the fact, something traditionally shot images don’t allow for.

1. Open the Photos app.
2. Select any image you shot in Portrait mode.
3. Select Edit.
4. You’ll see the F button up top, showing you which aperture you used for the picture. Tap on it.
5. A similar slider will show up. Edit it to your liking and hit Done.

Tips for using F stop settings for the best results

I always tell people that bokeh or blurry backgrounds don’t make good images on their own. There are other important factors to consider. Not to mention, over-using this blur effect can actually ruin a photo.

When not to use a wide aperture or F Stop

Because nice bokeh is usually created mainly by a narrower depth of field, this means that more of the image will be left out of focus. This can become a problem when, for example, you’re shooting a picture of a group. People often pose in different positions, at varying distances from the photographer. It’s common to see some people blurred out when the aperture is too wide. This is often the case when people are too far away, or closer than the area you focused on.

Additionally, it’s important to note that sometimes the background is essential. For example, what’s the point of taking a picture of yourself with the Eiffel Tower if the structure is barely recognizable because of so much blur? Sometimes you want to be able to see what’s out there!

When it’s OK to blur

All that said, using a nice bokeh can be fun, and make an image look great. It’s often recommended to do this when shooting a portrait in which you want the subject to be the main focus of an image. The blur can eliminate distractions, and possibly even enhance the look of an image.

It’s also lovely to see in macro photography, in which you want to take pictures of tiny things and don’t want the background getting in the way.

Focus on the fundamentals

Something I always tell beginner photographers is that if a picture doesn’t look good with everything in focus, chances are it won’t look good with parts blurred out, either. While the bokeh can look interesting and isolate a subject efficiently, other more important factors must be considered. Study composition, color theory, and play with unique angles. There are many things you can do to make an image look great! Here are some important photography tips to consider.

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