The aperture is the opening in the lens that allows light to enter the camera and onto the sensor or film. The size of this opening can be adjusted by changing the aperture settings. Take a look at the picture of a lens aperture above. Notice the adjustable blades that can move to adjust the size of the opening.

Introduction to Bokeh

Bokeh, derived from the Japanese word "boke" meaning "blur" or "haze," is a term used in photography to describe the aesthetic quality of the out-of-focus areas of an image. It is often considered a hallmark of professional photography, adding a dreamy, artistic touch to portraits, macro shots, and night scenes. Bokeh is not just about the blur itself, but about how the lens renders the out-of-focus points of light and how this blur contributes to the overall feel and composition of the photograph.

The Science Behind Bokeh

Bokeh is created when parts of an image are out of the depth of field, meaning they are not within the range where the lens can sharply focus. This usually happens when a photographer uses a wide aperture (a low f-number like f/1.8 or f/2.8). The larger the aperture, the shallower the depth of field, resulting in more pronounced bokeh.

The quality of bokeh depends on several factors, including the lens design, the shape of the aperture blades, and the distance between the subject and the background. Circular aperture blades tend to produce more pleasing, rounded bokeh, while polygonal blades can create bokeh with edges that mimic their shape.

Types of Bokeh

1. Creamy Bokeh: This type of bokeh is smooth and uniform, often described as "buttery" or "creamy." It blends seamlessly into the background, providing a soft, pleasing effect that enhances the subject.

2. Soap Bubble Bokeh: Characterized by bright edges and a distinct shape resembling soap bubbles, this bokeh is often produced by vintage lenses and can add a whimsical, nostalgic feel to images.

3. Swirly Bokeh: As the name suggests, swirly bokeh has a circular motion that gives the background a swirling effect. This type is commonly seen in photos taken with certain vintage lenses, such as the Helios 44-2.

4. Nisen Bokeh: Nisen bokeh, also known as "double-line bokeh," appears as if each point of light is doubled. It is generally considered less desirable as it can distract from the main subject, but some photographers use it creatively for artistic purposes.

Achieving Beautiful Bokeh

To achieve beautiful bokeh in your photos, consider the following tips:

1. Use a Wide Aperture: Set your lens to the lowest f-number possible to create a shallow depth of field.

2. Get Close to Your Subject: The closer you are to your subject, the more pronounced the background blur will be.

3. Increase the Distance from the Background: Ensure there is a significant distance between your subject and the background to maximize the blur effect.

4. Choose the Right Lens: Prime lenses with wide apertures (e.g., 50mm f/1.8, 85mm f/1.4) are excellent for creating bokeh.

5. Consider the Background: Points of light, such as fairy lights or reflections, can create beautiful bokeh shapes and enhance the overall effect.

Creative Uses of Bokeh

Bokeh is not just for achieving a pleasing background blur; it can also be used creatively to enhance the mood and story of an image. Here are some creative uses:

1. Portrait Photography: Use bokeh to isolate your subject from a busy background, drawing attention to their face and creating a professional look.

2. Night Photography: Capture stunning bokeh by photographing city lights or illuminated decorations, adding a magical touch to your night shots.

3. Macro Photography: Highlight tiny details of your subject while rendering the background into a smooth, non-distracting blur.

4. Abstract Photography: Play with different light sources and shapes to create unique, abstract images that focus on the bokeh itself.

Bokeh is a powerful tool in photography that goes beyond simple background blur. It adds depth, emotion, and artistic flair to your images. By understanding the principles behind bokeh and experimenting with different techniques, photographers can create visually stunning photos that captivate and inspire. Whether you're shooting portraits, landscapes, or abstract art, mastering the art of bokeh will elevate your photography to new creative heights.
 

How is aperture size measured?

The size of the aperture is measured in f-stops. Here’s where things get a bit weird though. The smaller the f-stop value, the wider the aperture. Conversely, the bigger the f-stop value….. you’ve guessed it, the narrower the aperture. There are very reasonable and logical mathematical reasons for this which I have no intention of going into here simply because the Maths is rather messy.

The 𝒇-stop numbers are calculated using this formula: 𝒇/N = d, where 𝒇 is the lens’ focal length, N is the 𝒇-number (i.e. 2 or 2.8), and d is the diameter of the lens’ aperture. The area of an aperture is πr² or π(d/2)² — since a radius r is half of the diameter. Substituting the diameter for 𝒇/N, an aperture’s area becomes π((𝒇/N)/2)² or π(𝒇/2N)².

Now, let’s assume we’re working with a lens with a 50mm focal length and a maximum aperture of 𝒇2. To decrease the exposure by half (i.e. by a single stop), we’ll need to half our aperture’s area. Using the formula above, we’ll get:

½(π(50/(2×2))²) = π(50/2𝒙)²

Where 𝒙 is the 𝒇-number for an aperture that would have half an area of 𝒇2 and thus one stop slower. Solving that, we’ll get:

½(π×12.5²) = π(50/2𝒙)²

245.4369260617 = π(50/2𝒙)²

78.125 = (50/2𝒙)²

8.8388347648 = 50/2𝒙

8.8388347648×2×𝒙 = 50

17.6776695296×𝒙 = 50

𝒙 = 2.8284271248

And so goes the progression: 𝒇2, 𝒇2.8, 𝒇4, 𝒇5.6, 𝒇8, 𝒇11, 𝒇16, etc.

What effect does our choice of aperture have on the look of our photograph?

The most obvious effect the aperture setting has on our photograph is the depth of field. In simple terms, this refers to how much of our final image is acceptably sharp.

In slightly more detailed terms, it refers to the distance between the closest and farthest areas in a photo that appear acceptably sharp. If you set a wide aperture, the depth of field will be shallow. This means that only part of your final photograph will be sharp, and the rest will be blurred.

If you set a narrow aperture, the depth of field will be deep. This means that all of your photograph from the foreground to the background should be acceptably sharp.

For very wide apertures such as f1.2, the depth of field may be no more than a few millimetres. This can make focusing very tricky especially if the subject (or photographer) is moving even slightly. A sturdy tripod and/or avoiding too much alcohol

can be useful in this situation. You might notice that there is about double the

amount of depth of field behind the point of focus as in front of it. We will come back to this point shortly.

Although using a wide aperture to create a shallow depth of field is often used by portrait photographers, it can also be used creatively in other situations.

Aperture affects shutter speed, and a mid-range aperture gives me enough depth of field

combined with a fast enough shutter speed so that I don’t blur the photos through camera shake.

For now, just know that wide apertures tend to result in faster shutter speeds and narrow apertures tend to result in slower shutter speeds.

It should also be noted that it is at these midrange apertures that lenses are often at their sharpest.

Lesson learnt. Always double check your settings! 

Bokeh

The term “bokeh” originates from the Japanese word “boke”, which translates to blur, as well as the Japanese term “boke-aji”, which translates to blur quality. The visual quality of the out-of-focus areas of a photographic image, especially as rendered by a particular lens.

Lake Tyrell Sunset Saltworks

Bendigo Art Gallery Lyttleton Terrace, Bendigo

The term became popular in English photography terminology in 1997, when it was used in a photography magazine, and the editor decided to alter the spelling of the word from “boke” to “bokeh” to be closer to the pronunciation. Many books and articles on photography started to use the term shortly afterwards. It has also been spelt as “boke”, but these days the most common spelling in English is “bokeh”.

Bendigo Bendigo

Bendigo Bloom Festival

In terms of the pronunciation, there are a variety of thoughts on the subject. In fact, there is much discussion online regarding how to properly pronounce the word bokeh, with suggestions including bo-key, boh-key and bo-kay.

Bendigo Bloom Festival

Bendigo Tulips

Bendigo

According to Wikipedia, Mike Johnson (the editor who popularized the term) has said the correct pronunciation is bo-key. “Bo” is pronounced how you would say the start of bone, and “Ke” is pronouced how you would start Kenneth. There is equal stress on both syllables.

Hosier Lane

Tsukiji Fish Market, Tokyo

First, let’s go over a quick overview of focus and how it works in photography. When you point your camera at a subject, you will usually focus on that subject. Everything in the shot that is the same distance from the camera as the subject will also be in focus. In practice, this usually means everything to the left and right of the subject will be sharp.

Elements that are closer to the camera then the subject, or further away from the camera than the subject, will have varying degrees of focus. The closer they are to the subject, the sharper they will be, the further away from the subject, the blurrier they will be.

Depth of field dictates how much of the scene in front of and behind the subject is in focus. A shallow depth of field means that only a small part of the scene will be in focus, whereas a wide depth of field means more of the scene will be in focus. Here’s another animal based example to demonstrate different depths of field.

Kilcunda

Melbourne

Maple

Paul Cathedral

Fence

Neons Night