Photographing a statue in dim light, you face a dilemma: one bright shot or many dim ones from different angles. The first is plagued by graininess from too few photons, the second by overlapping details. X-ray micro-scanners suffer from the same troubles. Scientists derived a general rule: regardless of strategy, the minimum resolution at any point in the image depends only on the total number of captured photons. And this relationship is treacherous — to double the clarity, you need eight times as many photons (cube root). It's as if a photographer in twilight, to get a twice-as-detailed shot, had to wait not one second but eight. Practical payoff: knowing this, you can precisely calculate the optimal ratio of flashes to angles. The researchers created an open calculator: plug in your tomograph parameters and get a resolution map.
To double the clarity, you need eight times as many photons — much like a twilight photographer would have to gather light not for one second but eight, to reveal details twice as fine.