Ultimate Depth of Field & Background Blur Calculator for Photographers

Compare lenses, visualize blur, make better photography decisions
About This Tool

Photographers often wonder which lens produces the best background blur (bokeh) and depth of field (DOF) for their shots. Understanding how different focal lengths, apertures, and sensor sizes affect blur can be challenging. Our advanced lens comparison tool makes it simple with precise calculations visualized in an interactive graph. Compare multiple lenses side by side to find the perfect lens for your desired background blur effect. Add lens configurations, select your subject size, and see instant visual results!

Lens Comparison Settings

Blur Comparison Graph

Lens Comparison: Background Blur vs. Distance

Higher values mean more blur

Generated by HowMuchBlur.com

Distance between subject and background

Subject Size Selection:

meters
Update Graph Manually

Changes automatically update after 1 second

Adjust Distance Range:

Use this slider to customize the subject-to-background distance range in the comparison graph:

Understanding Depth of Field & Background Blur

What is Depth of Field (DOF)?

Depth of Field refers to the zone in an image where objects appear acceptably sharp. A shallow depth of field creates a narrow zone of focus that separates the subject from the background, while a deep depth of field keeps more of the scene in focus. The DOF is controlled by several factors including aperture, focal length, and the distance between the camera and the subject.

What is Bokeh?

Bokeh refers to the aesthetic quality of the blur in out-of-focus areas of an image. The term comes from the Japanese word "boke" (ボケ), which means "blur" or "haze". Good bokeh is characterized by smooth, pleasing out-of-focus areas, especially in the highlights. The design of the lens, particularly its aperture shape, significantly affects the quality of bokeh, with premium lenses often featuring circular aperture blades that create more pleasing out-of-focus highlights.

Interpreting Graph Results

When analyzing the graph results, remember that background blur increases with distance between your subject and background, regardless of lens specifications. For meaningful photography results, consider your specific shooting scenario and the actual subject-to-background distance in your composition. The graph displays the theoretical blur as a percentage of the total image width, providing a standardized way to compare different lenses.

Professional Photography Insights:

  • Wider apertures (smaller f-numbers) are most effective for creating blur with closer backgrounds
  • Longer focal lengths become increasingly important for creating background blur when the background is more distant
  • Each lens produces unique bokeh characteristics beyond just the blur amount (quality, smoothness, highlight rendering)
  • Wider focal lengths capture more of the scene, potentially including background elements at varying distances
  • The blurriness perceived in real-world shooting can differ from theoretical calculations due to lens design quality

Factors Affecting Background Blur

Aperture (f-stop)

Aperture directly affects background blur. A wider aperture (smaller f-number like f/1.4) creates more background blur than a narrower aperture (larger f-number like f/8). This is because a wider aperture creates a shallower depth of field. Premium portrait lenses often feature extremely wide maximum apertures (f/1.2 or f/1.4) specifically to create creamy background blur.

Focal Length

Longer focal lengths (telephoto lenses) tend to create more background blur than shorter focal lengths (wide-angle lenses) when maintaining the same framing of your subject. This is because telephoto lenses compress perspective, magnifying the background blur effect. Portrait photographers often prefer focal lengths between 85mm and 135mm for this reason, as they provide flattering perspective and excellent background separation.

Sensor Size (Crop Factor)

Larger sensors (full-frame or medium format) typically produce more background blur than smaller sensors (APS-C or Micro Four Thirds) when using the same focal length and aperture. This is why full-frame cameras are often preferred for creating creamy, blurred backgrounds. The crop factor of your camera directly affects the effective focal length and depth of field characteristics of your lenses.

Distance Relationships

The relative distances between you, your subject, and the background heavily influence blur. The closer you are to your subject and the further the background is from your subject, the more pronounced the background blur will be. This is a key consideration for portrait photographers when selecting shooting locations and positioning their subjects relative to the background elements.

Photography Tips for Creating Beautiful Bokeh

  1. Use a prime lens with a wide maximum aperture (f/1.8 or wider) for the most pronounced bokeh effect
  2. Increase the distance between your subject and the background to enhance blur
  3. Move closer to your subject when possible to increase the relative background distance
  4. Look for backgrounds with small light sources or highlights to create pleasing bokeh balls
  5. Consider the quality of bokeh, not just the amount - some lenses produce smoother, more pleasing bokeh patterns
  6. Use longer focal lengths (85mm, 105mm, 135mm) for flattering portraits with beautiful background separation
  7. Shoot in locations with complex background textures and colors for more interesting bokeh effects
  8. When shooting portraits, ensure the eyes are in sharp focus while allowing other elements to fall into pleasing blur
  9. Try shooting during golden hour when light is softer, creating more pleasing highlight bokeh
  10. Experiment with different apertures and distances to find the ideal balance between subject sharpness and background blur

Creative Applications of Bokeh

Portrait Photography

In portrait photography, bokeh is used to isolate subjects from potentially distracting backgrounds. The soft, out-of-focus areas create a dreamy, professional look that draws attention to the subject. Portrait photographers often seek lenses specifically for their bokeh characteristics.

Macro Photography

In macro photography, the extremely close focusing distances naturally create dramatic background blur. Photographers use this effect to isolate tiny subjects against smooth, colorful backgrounds, creating striking visual contrast between sharp details and soft surroundings.

Night and City Photography

City lights at night can transform into beautiful bokeh balls when shot with the right lens and settings. Photographers often use this technique to create atmospheric urban compositions where out-of-focus lights become an artistic element rather than a distraction.

Wildlife Photography

In wildlife photography, background blur helps separate animals from busy forest or field backgrounds. The long telephoto lenses used in this genre naturally create significant background blur, which can be enhanced by positioning yourself to maximize the distance between subject and background.