# In femtosecond Raskar photography of a light pulse, why is the light pulse not length contracted?

If length contraction is a physical phenomenon, as many (not including myself) believe, then at a trillion frames per second, Raskar photography should be able to pick up the length contraction of an ordinary high speed bullet just by counting the number of frames it occupies when moving. Just like an atomic clock, the Raskar method should be able to act like a high resolution time microscope to see relativistic effects for low relativistic speeds.

So if a bullet might appear length contracted, why isn't the light pulse? We would have the same perspective to the bullet as to the light pulse. The light pulse is created by a clock in our frame but the clock of the light pulse's frame should be at a standstill relative to ours which means we shouldn't even be able to see the light pulse's frequency which should also be at a standstill.

Let's be extremely charitable and say you're talking about a bullet from a high-power rifle, which has a muzzle velocity of around $$1200$$ m/s (source: https://en.wikipedia.org/wiki/Muzzle_velocity). The Lorentz factor at that speed is $$1.000002$$, so the length of the bullet will decrease to $$99.9998\%$$ of its at-rest observed size. Given that a typical bullet for one of these rifles (say, the .220 Swift: https://en.wikipedia.org/wiki/.220_Swift) is around 12 mm long, the magnitude of the length contraction will be around $$24$$ nm. Since the wavelength of the light used to observe the bullet is between $$400$$ and $$700$$ nm (which sets the smallest length scale that a visible-light camera can reliably observe), this isn't really observable by any camera that uses visible light.