Blink-Free Photos Calculator — How Many Shots to Take
Taking a group photo? This calculator tells you how many shots to take to virtually guarantee at least one where everyone has their eyes open — based on group size, individual blink probability, and your desired confidence level.
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Photos to take for your chosen confidence of at least one blink-free shot
- 1
Per-person eye-open probability
1 − 10 % = 0.9 - 2
All-eyes-open probability per shot (5 people)
0.9ⁿ = 0.5905Probability every person in the group has eyes open simultaneously. - 3
Shots for target confidence
⌈ln(1 − 99 %) ÷ ln(1 − 0.5905)⌉ = 6
How does this calculator work?
The probability all n people have eyes open in one shot is (1 − p)ⁿ. To hit a 99% confidence of at least one blink-free frame, take k = ⌈ln(0.01) / ln(1 − (1 − p)ⁿ)⌉ shots. For a group of 5 at a 10% blink rate that is about 4 shots.
Formula
How this is calculated
Each person blinks involuntarily about 15–20 times per minute, with each blink lasting roughly 150–400 ms. For a typical shutter speed, the probability that any one person blinks during a shot is around 8–12%. If p is that individual blink probability, the probability that all n people in the photo have their eyes open simultaneously in a single shot is q = (1 − p)ⁿ — it shrinks rapidly as the group grows.
The expected number of shots to capture one perfect result is 1/q. For a given confidence level C (e.g., 99%), the minimum number of shots k is the smallest integer satisfying 1 − (1 − q)ᵏ ≥ C, which rearranges to k = ⌈ln(1 − C) / ln(1 − q)⌉.
This model assumes each person's blink is independent and that the blink probability is constant across shots — reasonable for candid photography. Burst mode or a photographer watching for blinks can improve results beyond what this model predicts. Adjust the blink probability down for subjects who are attentive and prepared.
Frequently asked questions
For casual candid shots, 10% per person per photo is a good default. For posed shots where subjects are looking at the camera and ready, 5–8% is more realistic. Increase it for children or fast shutter scenarios.
The probability all eyes are open is (1 − p)ⁿ, which drops exponentially with each additional person. For 10 people at 10% blink rate the chance of a perfect shot is only ~35%, so on average you need nearly 3 shots just to expect one success — more to be 99% confident.
Yes — burst mode fires many frames per second, effectively running multiple independent trials rapidly. Use this calculator's recommendation as the total number of frames to review, and pick the best one.
TG we-Calculate Editorial Team. (2026). Blink-Free Photos Calculator — How Many Shots to Take [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/blink-free-photos-calculator
TG we-Calculate Editorial Team. "Blink-Free Photos Calculator — How Many Shots to Take." TG we-Calculate. 2026. https://we-calculate.com/calculator/blink-free-photos-calculator.
TG we-Calculate Editorial Team, "Blink-Free Photos Calculator — How Many Shots to Take," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/blink-free-photos-calculator
@misc{wecalculate_blink_free_photos_calculator, title = {Blink-Free Photos Calculator — How Many Shots to Take}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/blink-free-photos-calculator}}, year = {2026}, note = {TG we-Calculate} }
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