BOKEH – WHAT, WHY & HOW

Written by | Featured, Photo Techniques, Tutorials

We welcome guest writer Jess (@jesseesolo) to the platform with a special Tutorial feature as she breaks down Bokeh and what exactly it is all about.

00_ImBatman

Straight-out-of camera bokeh Bat Signal

Nikon D90 | 105 Micro f/2.8 | Shot at f/3.5 

Often mispronounced and misunderstood, “bokeh” (bo·keh \ˈbō-kā, -kə\ ), or the blurred quality/effect in the out of focus area of a photograph is not only fun to play with, but also easy to alter.  By placing a custom aperture disc in front of your lens and shooting wide open, you can control the shape of the bokeh balls (pause for giggles) in the background or foreground of your images. 

Focus racking showing a light source both in and out of focus with an aperture disc in place.

This 10-minute project involves simply cutting any small shape in a piece of cardstock, placing it in front of your lens and shooting wide open.

01_lens-text.jpg

Batman’s Aperture disc

TOOLS AND SUPPLIES

  • Camera with a fast prime lens
  • Compass, or your lens cap
  • Ruler
  • Pencil/Marker
  • Black cardstock/construction paper
  • Scalpel/craft knife
  • Scissors
  • Cutting mat

02_ Materials

It’s arts and craft time, so stop eating the paste and bust out the construction paper.

DISC SIZING

To determine the size of the cardstock disc needed for your lens, either measure the inner diameter of the lens’s filter ring or look on the inside of your lens cap for the size in millimeters and downsize 1-2 mm.

Measure the diameter of your filter ring or look inside your lens cap, in this case, the size is 52mm.

On a piece of construction paper use a compass to trace a circle sized for your lens. The small rectangular tabs are optional; they help in seating and removing the aperture disc. One tab is enough. I like symmetry, so I use two.

If you don’t have a compass or you don’t want to measure, trace your lens cap and cut on the inside of the line so the filter will sit inside the threads and closer to the front element of the lens.   

05_Draw.jpg

Arts and crafts time with a side of geometry

APERTURE SIZE

The design you will be cutting out of the construction paper disc will serve as a new aperture for your lens. It needs to be smaller than the lens’ largest aperture. The math is a little more complicated than this, but for our purposes, simply divide the focal length of the lens by its largest aperture and go a little smaller.   For example, with a 50mm f/2, you should have a cutout smaller than ~23mm since 50mm/2 = 25mm. Now subtract ~2 mm for a little wiggle room, and that takes us to 23mm. 

DESIGN & CUT

Now that you know the maximum size of the new aperture draw the design of your choice in the center of the construction paper circle.

Now cut out your shapes and discs. Start with the center design. This will give you more room to hold onto the construction paper. Then cut out the circle and tabs.

CAMERA SETTINGS

Set your camera to Manual or Aperture Priority and use your largest aperture (f/4 to f/1.2).

08_Groot bubble.jpg

Canon 6D | 100 mm macro f/2.8 | Shot at f/2.8 | No aperture disc 

09_Groot E.jpg

Canon 6D | 100 mm macro f/2.8 | Shot at f/2.8 | With aperture disc

Note the rounded off edges of the bokeh “E.” This is due to the size of the cutout being too large for this lens.

NOTES

  • With smaller or intricate designs autofocus will struggle, so try these steps:
  • Place camera on a tripod
  • Pre-focus on your subject
  • Set camera to manual focus
  • Place the disc in front of your lens taking care not to change the focus
  • Meter the scene
  • Take photos
  • Check your exposures and bracket as necessary
  • Practice

Variables to play with:

    • Camera-subject-background distances 
    • The angle of the light source if using a reflective background 
    • Cutout size

A Full Frame sensor will yield the best results. However, APS-C systems work quite well. Please note that I have no experience with M4/3 system, so I have no opinion yet.

If you aren’t a DIY person, there are some commercially available options. My favorite of these is Lensbaby’s Creative Bokeh Optic and Composer  https://lensbaby.com/product/creative-bokeh-optic/ . Their discs are magnetic, come in various designs and include blank discs for you to cut out your own design.

09_Strange.jpg

Sony A7II | Lensbaby Velvet 85 f/1.2 | Shot at f/4

Try it out on lens flare.

I may be the only person on the planet that is as addicted to lens flare as J.J. Abrams is, so of course, I had to try it. I grabbed my two trusty droids, waited for the Sun to be low on the horizon and tossed a cutout in front of my favourite lens and got the shot I wanted. I write this with lots of love, but Suck it, J.J.  : )

10_Rebel Flare.jpg

Sony A6000 | Lensbaby Velvet 85 f1.2 | Shot at f/3 ish in false-color near-infrared

If you have any questions or want to talk tech, gear or just want to share your use of this technique, tag me @JesseeSolo on Instagram.

11_Questions.jpg

Nikon D90 | Nikon 105 Micro 2.8 | Shot at f/3.3

Stay tuned to Exclu for all the latest tutorials and guides from across the toy community.

Last modified: June 9, 2019

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