# HDR Merge Online - Exposure Fusion & Single-Image HDR Look

> Merge 2–7 bracketed exposures with MTB alignment, Mertens exposure fusion and ghost reduction — no camera response needed — or give one photo an HDR look.

- URL: https://qilingtools.com/en/image/hdr
- Category: Image Tools (https://qilingtools.com/en/image)
- Tags: [Image](https://qilingtools.com/en/tags/image), [Photo Editing](https://qilingtools.com/en/tags/photo), [Creative Effects](https://qilingtools.com/en/tags/effects)
- Last updated: 2026-10-26
- Price: Free, no sign-up
- Privacy: Runs locally in the browser; files are never uploaded

Backlit scenes, sunsets and interiors with windows are hard to capture in one shot, which is why photographers bracket: the same scene at −2 EV, 0 and +2 EV. Drop in 2 to 7 brackets and the tool first aligns hand-held shifts with MTB (median threshold bitmaps): each frame is binarised at a brightness percentile, which makes the comparison insensitive to exposure, and the offset is searched coarse to fine on an image pyramid. The frames are then combined with Mertens exposure fusion: every pixel of every frame is scored for local contrast, saturation and well-exposedness (closest to mid-grey wins), the weights are normalised and the images are blended level by level on a Laplacian pyramid, giving smooth transitions without seams — no camera response curve or separate tone mapping needed. When people, cars or leaves moved between shots, ghost reduction keeps the middle exposure as the reference and lowers the weight of areas that disagree with it. The second mode gives a single photo an HDR look: log luminance is split into base and detail layers with a guided filter, the base layer’s range is compressed and the detail is boosted, with clarity, shadows, highlights and vibrance on top, so skies keep their colour and shadows open up without the usual halos. The preview updates live and the export is recomputed at the chosen size in a Web Worker, entirely in your browser.

## How to use

1. Pick a mode: merge brackets (drop 2–7 exposures of the same scene) or single-image HDR look (drop one photo)
2. Enable auto-align and ghost reduction if needed, then adjust the fusion weights and the tone controls — range compression, detail, clarity, shadows and highlights
3. Choose the output size and export JPG or PNG

## Features

- Merge 2–7 bracketed exposures
- MTB median-threshold-bitmap alignment with pyramid search
- Mertens exposure fusion with Laplacian pyramid blending
- Ghost reduction for moving subjects
- Adjustable contrast, saturation and well-exposedness weights
- Single-image HDR look via guided-filter base/detail split
- Clarity, shadows, highlights and vibrance
- Worker processing, JPG / PNG export

## FAQ

### How many shots do I need, and how far apart?

Three usually do: −2 EV, 0 EV and +2 EV; for very strong backlight shoot five, one or two stops apart. The darkest frame should keep bright areas such as the sky or lamps from clipping, and the brightest should show the shadows clearly. Burst mode or your camera’s auto-bracketing is easiest; keep aperture and white balance fixed and vary only the shutter speed.

### Can I merge hand-held shots?

Yes. Auto-align corrects shifts between the frames (up, down, left, right), and the detected offsets are listed under the preview. It doesn’t correct rotation or perspective changes, so hold steady and use burst mode to keep the gaps short; a tripod gives the best results. Edges that don’t overlap after alignment are cropped away.

### How is exposure fusion different from traditional HDR?

Traditional HDR recovers the camera’s response curve from the exposure times, builds a floating-point radiance map and then tone-maps it back to a normal picture, so it needs accurate exposure data. Mertens exposure fusion works directly on ordinary photos, picking the best-exposed parts pixel by pixel and blending them smoothly across scales. It needs no EXIF exposure information and looks natural rather than “overcooked”; add range compression and detail if you want a stronger look.

### Why are there ghosts in my merged photo?

Ghosts come from things that moved between shots — people, cars, water, leaves in the wind. Raise “Ghost reduction”: the middle exposure becomes the reference and areas in the other frames that disagree with it lose weight. The more and the larger the moving objects, the higher the strength needed. If the frames themselves are misaligned, make sure auto-align is on first.

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