Photo Background Blur & Vignette Studio | 100% Private

The Optics of Depth of Field & Synthetic Bokeh

In optical physics, Depth of Field (DoF) is determined by four variables: lens focal length, physical aperture diameter, subject distance, and sensor format. Full-frame cameras equipped with wide-aperture portrait lenses (such as an 85mm f/1.4) isolate subjects by allowing out-of-focus background light rays to blur into soft circular discs.

Smartphone cameras possess miniature sensors with tiny physical focal lengths (typically 4mm to 7mm), yielding nearly infinite depth of field where everything from two feet to infinity remains in sharp focus. Digital background blur tools simulate physical aperture physics through radial masking and spatial Gaussian convolution.

Privacy Obfuscation vs. Aesthetic Enhancement

Application Mode	Blur Radius	Focal Zone	Primary Objective
Portrait Bokeh	15 – 25 px	Centered on face/torso (40–50% radius)	Separates subject from distracting backgrounds with cinematic elegance.
Privacy Obfuscation	35 – 50 px	Tight focal bounds (20–30% radius)	Blurs bystander faces, street names, computer monitors, and domestic spaces.
Dramatic Vignette	5 – 15 px + 40% Shading	Gradual feathering across 60% radius	Guides viewer gaze inward by darkening optical edges.

Frequently Asked Questions (US Standards)

How does the in-browser background blur and focal mask work?

The tool renders two passes of your image on an HTML5 Canvas: a bottom layer with a hardware-accelerated Gaussian blur filter (ctx.filter = 'blur(...)'), and a top layer rendering the unblurred original image clipped to an elliptical focal path with a soft radial alpha gradient. This creates a smooth optical transition simulating shallow depth of field (bokeh).

What is optical bokeh and the Circle of Confusion in photography?

Optical bokeh (from the Japanese 'boke', meaning blur) describes the aesthetic quality of out-of-focus highlights rendered by a camera lens. When light rays pass through a wide-aperture lens (f/1.4 or f/2.8), rays originating outside the focal plane converge ahead of or behind the sensor, rendering point sources of light as blurry discs known as the 'circle of confusion.' Digital portrait blur replicates this optical effect mathematically.

Can I use this tool to obscure bystanders or sensitive background objects?

Yes. In addition to aesthetic portrait enhancement, blurring the perimeter background effectively conceals bystanders' faces, license plates, house numbers, or confidential office whiteboards before sharing photos on social media or corporate intranets.

How do I move the sharp focal point on the photo?

Simply click or drag anywhere across the live preview canvas. The center of the sharp elliptical focus zone immediately snaps to your cursor coordinates, allowing you to highlight subjects positioned off-center according to the Rule of Thirds.

Are any image files uploaded to a cloud server?

No. The entire compositing pipeline, spatial convolution, and radial alpha gradient clipping execute 100% client-side in your local browser sandbox. Zero bytes of your photographs are transmitted across the internet.