How many brackets do I need for HDR?

It depends on the scene dynamic range and your camera. A typical interior with bright windows might have 12-14 EV of range. If your camera captures around 8 EV of usable single-shot range, you need brackets to cover the remaining 4-6 EV — at 2 EV steps that is 3-4 frames. Note 8 EV is a conservative figure (closer to an in-camera JPEG or an older sensor); a modern full-frame raw sensor reaches roughly 13-15 EV at base ISO (per DxOMark and Photons to Photos), so a single raw file often covers an outdoor scene with no bracketing at all.

What step size should I use?

For most HDR work, 1 or 2 EV steps work well. Smaller steps (0.5-1 EV) give smoother blending in the HDR merge but require more frames. Larger steps (2-3 EV) minimise the number of shots but may leave gaps in tonal coverage.

Should I bracket aperture or shutter speed?

Always bracket shutter speed. Changing aperture changes the depth of field between frames, making alignment and merging much harder. Keep aperture and ISO constant, and only vary the shutter speed.

What is the dynamic range of a typical scene?

Outdoor scenes typically range from 10-14 EV. Interiors with windows can reach 15-18 EV. A sunset might be 12-16 EV. Overcast landscapes may only be 6-8 EV, often within a single exposure.

How is the bracket sequence ordered?

The sequence is centred on the metered exposure (0 EV) using equal EV steps. An odd number of frames is symmetric (for example −2, 0, +2 EV). An even number is skewed one step toward underexposure (for example −4, −2, 0, +2 EV) so the extra frame protects the brightest highlights, which clip irrecoverably, rather than the shadows, which merge more forgivingly.

PhotoCalcs

HDR Bracket Calculator — Plan Your Bracket Sequence

Calculate the number of bracketed exposures needed to cover a scene's dynamic range for HDR photography.

Scene Dynamic Range

Darkest-to-brightest EV span: ~10-14 outdoors, 15-18 for an interior with bright windows

Camera Dynamic Range

Usable single-exposure DR: ~7-8 EV for JPEG, 13-15 EV for a modern full-frame raw

Bracket Step SizeEV difference between consecutive frames

How We Calculate This

The number of bracketed frames depends on three factors:

Scene dynamic range (total EV span from darkest shadows to brightest highlights)
Camera dynamic range (EV range captured in a single exposure)
Step size (EV difference between consecutive brackets)

Frames = ceil((Scene DR − Camera DR) ÷ Step) + 1

The brackets are centred on the metered exposure (0 EV), with an equal EV step between consecutive frames. Sequences with an odd number of frames are symmetric (e.g. −2, 0, +2 EV); sequences with an even number are skewed one step toward underexposure (e.g. −4, −2, 0, +2 EV) to protect the brightest highlights.

Frequently Asked Questions

Related Calculators

Exposure Triangle Calculator

Balance aperture, shutter speed and ISO to achieve correct exposure. Adjust one setting and see how the others compensate. Free online calculator.

EV Calculator

Calculate Exposure Value from your camera settings or convert between EV, lux and foot-candles. Ideal for matching light meter readings. Free calculator.

Reciprocity Calculator

Compensate for reciprocity failure when shooting long exposures on film. Enter metered time and film stock for corrected exposure. Free calculator.

Sunny 16 Calculator

Estimate correct exposure settings using the Sunny 16 rule for outdoor photography. Select lighting conditions for instant aperture and shutter recommendations.

Flash Exposure Calculator

Calculate flash power from guide number, subject distance and aperture. Work out the correct flash-to-subject settings for any strobe. Free calculator.

Last updated: February 2026

All calculations are estimates based on standard optical and photographic formulas. Results may vary with specific equipment.