Use the free HDR Bracketing Calculator below. Everything runs in your browser, with no sign-up and no upload.
The sky is perfect, but the foreground is black. Or the room is perfect, but the window is blown white. No single exposure can hold both ends of a high-contrast scene. Bracketing can: several frames at different exposures, merged later into one image with detail everywhere.
What is HDR Bracketing Calculator?
HDR bracketing means shooting a sequence of frames from darker to brighter, usually centred on the metered exposure. Each frame is separated by a fixed step, often one or two stops. A scene spanning six stops with two-stop steps needs four frames: minus three, minus one, plus one and plus three stops relative to the middle. Merging software then picks the well-exposed parts of each frame. The calculator works out how many frames you need and the exact exposure of each one.
How it works
The tool divides the scene’s dynamic range by the bracket step and adds one frame, which gives the count. It then spaces the frames evenly around the middle exposure. If you enter a middle shutter speed, it also converts each frame’s offset into a real shutter time, so you can set the camera or check that your camera’s auto-bracketing covers the range. Note that changing the shutter speed between frames, rather than the aperture, keeps depth of field constant across the set.
How to use it
- Judge the scene’s range: meter the brightest important highlight and the darkest important shadow.
- Choose a step: one stop gives smoother merges, two stops covers the range with fewer frames.
- Enter the range, the step and your middle shutter speed.
- Shoot the sequence on a tripod, changing only the shutter speed, and merge the frames later.
Worked example
A sunset interior spans about six stops from the dark room to the bright window. With two-stop steps the calculator gives four frames: minus three, minus one, plus one and plus three stops. If the middle exposure is 1/60 second, the frames run from 1/500 second for the window to 1/8 second for the room. Merged, the window keeps its colour and the room keeps its detail. With one-stop steps the same scene would need seven frames and a smoother, but slower, merge.
Tips and limits
Use a tripod whenever the darkest frame is slower than about 1/30 second, and use a remote release so the frames align. Moving subjects, like people or trees in wind, can ghost in the merge; many merging tools have a de-ghost option for exactly this. Do not bracket by changing aperture, or the depth of field will shift between frames and the merge will look odd. And bracket for a reason: a low-contrast scene gains nothing from HDR, and the merged result can look flat and artificial.
Please note: photography exposure tools are educational calculators. Sunny 16 and Zone System figures are starting-point rules of thumb, and a meter reading governs in real shooting. Time-lapse figures assume the camera can sustain the interval, and buffer or card limits may intervene.
Frequently asked questions
How many stops of range does a typical scene have?
An overcast day may span five or six stops. A sunny interior with a bright window can span ten or more. Your camera captures roughly eight to twelve stops in a single raw frame, less in JPEG.
Should I shoot raw for HDR?
Yes, if your camera allows it. Raw frames give the merging software far more tone to work with than JPEGs.
Can I bracket by hand instead of using auto-bracketing?
Yes. Set manual exposure, take the middle frame, then change only the shutter speed for the darker and brighter frames. It is slower but gives full control.
Try the calculator above with your own numbers, and use the result as a planned starting point for your next shoot. A few minutes of planning before you press the shutter usually saves a whole session of corrections afterwards.