Background blur (bokeh)
Longer lenses, wider apertures and closer subjects all melt the background. Enter your setup to estimate how large the background blur circle will be on film.
The blur circle is how big a background point spreads on the film. Bigger means smoother, creamier bokeh. Relative to the 0.03mm sharpness circle tells you how out-of-focus it looks.
About this tool
Longer lenses, wider apertures and closer subjects all melt the background. Enter your focal length, aperture, subject distance and background distance to estimate how large a background point spreads on the film, which is how creamy the bokeh looks.
How to use it
- Enter the focal length and aperture.
- Enter the subject distance and the background distance.
- Read the background blur circle size in millimetres.
- Compare it to the sharpness circle to judge how blurred it looks.
FAQ
What makes a bigger blur circle?
A longer lens, a wider aperture, a closer subject and a more distant background all increase the background blur.
Is this the same as depth of field?
Related but different: depth of field is what is acceptably sharp; this estimates how strongly the out-of-focus background is blurred.