Sensor dynamic range is the full-well capacity divided by the read noise, both in electrons. Express it in stops with log2 or in decibels with 20 × log10. A sensor holding 40,000 e⁻ with 3 e⁻ of read noise has a 13,333:1 ratio, which is 13.70 stops or 82.5 dB.
Spec sheets and sensor reviews quote full-well capacity and read noise, but photographers think in stops. This calculator converts those two electron counts into engineering dynamic range for one sensor or a list of them, reports each in stops and decibels, and highlights the widest. Add the brightness range of a scene in EV to learn if one exposure can hold it or if bracketing is needed. A bar chart and table put the sensors side by side. The figure is the per-pixel engineering range at base ISO; tests such as photographic dynamic range normalise for print size and a noise threshold, so they usually report one to two stops less.
Give each camera a name, its full-well capacity and its read noise in electrons. Use Add sensor for more rows.
Optionally type how many stops separate the deepest shadow and brightest highlight you want to keep.
The table lists stops and dB per sensor and the bar chart ranks them; the chart downloads as PNG, SVG or CSV.
Result Best dynamic range (stops): 13.29
Widest-range sensor: Scientific CCD
Best range in decibels: 80
Contrast ratio (to 1): 10,000
Gap between best and worst (stops): 0
A 10,000:1 ratio is exactly 80 dB, or a little over 13 stops between the noise floor and saturation.
Result Best dynamic range (stops): 13.70
Widest-range sensor: Full-frame
Best range in decibels: 82.5
Contrast ratio (to 1): 13,333
Gap between best and worst (stops): 0
Headroom over the scene (stops): 1.7
40,000 e⁻ over 3 e⁻ of read noise gives 13.70 stops, leaving about 1.7 stops to spare on a 12-stop sunset.
Result Best dynamic range (stops): 14.87
Widest-range sensor: Low-noise
Best range in decibels: 89.5
Contrast ratio (to 1): 30,000
Gap between best and worst (stops): 2.91
The larger sensor holds three times the charge with less read noise, giving almost three stops more range.
DR (stops) = log2(FW ÷ RN); DR (dB) = 20 × log10(FW ÷ RN)
FWRNDRThe brightest signal a pixel records is its full well; the faintest distinguishable from noise is about one read-noise level. Their ratio is the dynamic range. One stop is a doubling, so the base-2 logarithm gives stops; image-sensor datasheets use 20 × log10 because they treat the signal as a voltage-like amplitude. Headroom is the best sensor's stops minus the scene's stops.
Sensor datasheets treat electron counts as an amplitude, like a voltage, and amplitude ratios use 20 × log10. On that scale one stop is about 6.02 dB, so 80 dB is roughly 13.3 stops.
Sensor manufacturer datasheets, astronomy camera specifications and independent photon-transfer measurements publish both in electrons. Review sites that measure raw files often list them per ISO setting.
Reviews often report photographic dynamic range, which demands a cleaner shadow than a signal-to-noise ratio of one and normalises to a fixed print size. Engineering dynamic range from this formula is usually one to two stops higher.
Spot-meter the darkest area that should keep detail and the brightest highlight, then count the EV difference between the two readings. A sunlit landscape with deep shade can exceed 14 stops.
The scene spans more stops than the sensor records in one frame. Exposure bracketing with HDR merging, a graduated filter, or fill light brings the scene back within range.
Larger pixels generally hold more electrons, which raises full-well capacity. If read noise stays similar, the ratio and therefore the stops grow with pixel area.
Using this tool in an assignment, article or report? Copy a citation, or a link for your website.
Tools Directory Editorial Team. (2026, October 9). Dynamic Range Calculator. Tools Directory. Retrieved October 27, 2026, from https://tools.milunir.com/photography/photography-planning/dynamic-range-calculator/
Tools Directory Editorial Team. “Dynamic Range Calculator.” Tools Directory, 9 Oct. 2026, https://tools.milunir.com/photography/photography-planning/dynamic-range-calculator/. Accessed 27 Oct. 2026.
Tools Directory Editorial Team. “Dynamic Range Calculator.” Tools Directory. Last modified October 9, 2026. Accessed October 27, 2026. https://tools.milunir.com/photography/photography-planning/dynamic-range-calculator/.
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