“What is the sharpest lens I could buy? How to avoid blurred images? My images are turning out soft: what am I doing wrong?”
If you are into photography, you should be familiar with such questions, and maybe, you have them too. It seems photography is all about getting a sharp image, isn’t it?
Not quite: things like intentional camera movement are used to create artistic motion blur. And then there is the famous, but often misunderstood, bokeh.
So, what is bokeh and why should you care about it?
What Does It Mean “Bokeh”?
Bokeh is a Japanese term that can be translated as Blur.
But a bokeh is not so much about having a blurred background as it is about the aesthetic quality of the blurring. The two aspects are related but are not the same.
Sometimes, bokeh is also referred to as the way the lens displays out-of-focus points of lights.
Remember: in photography, bokeh is a creative effect you intentionally introduce in the image, either by shooting in a particular way or using a particular lens.
What Is The Difference Between Bokeh And Background Blur?
Blurring the background is a common technique used to add depth to your image and let your target stand out more.
This technique is most often used in portraiture and can be achieved in many ways: by increasing the size of the lens aperture (smaller f-numbers), by choosing the focal length in relation to the camera-to-subject and subject-to-background distances.
For example, for a given camera-to-subject and subject-to-background distances, a wider aperture increases the blurring of the background when the focus is on your model.
Increasing the distance between your model and background also increases the background blurriness.
Above is an example background blur.
The resulting effect can be pleasant or not.
And this (below) is bokeh.
What Is The Bokeh Effect?
Bokeh can be used to help separate your model from the background.
But bokeh can also be used for crafting creative images by blurring points of lights present in the background. By blurring them, you make them so big that they become crucial background elements.
What Is Good & Bad Bokeh?
Particularly in portrait photography, photographers associate the quality of a lens bokeh to how “creamy” the blurred background looks like, that is how smooth it looks.
A bad bokeh is a blurred background that still has some details in it, although smudged: light tree twigs, edges, etc.
And if you look at how points of light are blurred, some lenses will give you nice round, smooth circles while others can render the point of lights with odd shapes.
Mirror lenses (catadioptrics) are a typical example of weird (for some, bad) bokeh, as the point of lights are rendered as donuts rather than circles.
The number of blades of the diaphragm and the aperture used also affects the quality of the bokeh.
How To Achieve Bokeh In Your Images
The lens you use is very important in achieving a good bokeh. The focal length, maximum aperture, number of blades in the diaphragm, and glass quality are all playing a role in getting bokeh.
But there are a few more things to consider.
The idea is to play with the depth of field so that when your subject is sharp and in focus, the background looks blurred and smooth.
- Work the distance: camera-to-subject and subject-to-background distances should be carefully chosen. The more distance you put between your subject and the background, the more blurred and smoother the background will be, even if you don’t have a very fast lens. If you cannot put much distance between the subject and the background, go closer to your target.
- Use a large sensor camera: for a given focal length, lens aperture, and camera-to-subject distance, the larger the sensor the shallow the depth of field, making it easy to blur the background.
- Prefer fast lenses with an aperture of f/2 or smaller. For a given camera, focal length and camera-to-subject distance, the wider the aperture, the shallower the depth of field. Plus, wide apertures help to have nicer out of focus point of light.
- For any given aperture and camera-to-subject distance, the longer the focal length, the shallower the depth of field.
How To Get Even More Creative With Bokeh: DIY Bokeh Masks
Bokeh is an artistic element, and you can get more creative than just rendering points of lights as circles, octagons, pentagons, and so on.
A simple way to create an even more artistic bokeh is to create a mask to place in front of your lens.
You can easily build it from a sheet of paper: with a compass, draw a circle the size of the lens. Then cut out your preferred shape from the center of the circle and place the paper mask on your lens.
Frame some lights, blur them greatly and place the mask in front of your lens to get a nice pattern of shapes.
Bokeh In Astrophotography
This is quite an odd idea: what would bokeh possibly have to do with astrophotography?
Well, creativity has no limits. While astrophotography is likely one of the more scientific types of photography, if you consider starry landscapes to be part of it, then creativity has found its place back.
And with that, bokeh! What are stars if not true points of lights? Find a subject you can image from up close and personal with a fast lens and those stars will create a dreamy bokeh.
Remember: wide-angle lenses have a very wide depth of field, so you want to be close to your target and use a very fast aperture.
Learning how to blur the background to make your subject stand out more is a great way to improve the quality of your photography, from portraiture to travel photography and even family snapshots.
And by learning how to create a good bokeh, it is the way to unlock your creativity and create more compelling and storytelling images.