User blog comment:Nice Things/Because Magic?/@comment-96.4.30.118-20130605191353/@comment-933831-20130605193354

 There are three main kinds of faster than the eye to be considered, the third of which is on an order of magnitude higher than the first two. Faster than the movement of the eyes themselves? This will make things appear out of focus and difficult to locate, and is determined by distance in the field of vision in relation to human eye movement speed. Faster than the brain's separation of one event from another? This effect is really the same thing as the first and cannot be focused on and tracked, repeating punches for example appearing as multiple blurs in exactly the same fashion as a helicopter blade. This is determined on this limit of the processing of the brain and the distance the movements occur over. Faster than a human can perceive? This will make a movement imperceptible, and is based on the limits of human time perception, as well as distance of the movement/field of vision. This is the level of speed required for true "teleportation speed" as it is described.

 Below 5 milliseconds (a 200th of a second), and peaking towards 1 millisecond (a 1000th) movements are tending towards imperceptibility for humans (This is NOT to be confused with human reaction time which the average is around 215 milliseconds, peaking at the physical limit of 100 milliseconds aka 1/10th of a second).

 In an experiment, under good circumstances, air force pilots were able to identify an aircraft flashed on the screen for a 220th of a second, but only in a darkened room in which the after-image lingered on the eye. There is a similar phenomena that occurs with sound, and is known as summing localization, in which two sounds are separated by so little time as to appear as the sum of their parts (1 to 5 milliseconds), so it's highly likely that this represents the same range of limitation of the brain. However, it is wise to use the minimum in any calculations rather than the peak.

 However, in a fight, good conditions aren't always available, and the feat may not necessarily be depicted as imperceptible to the readers of the manga despite the characters viewpoint. A character witnessing such a feat at close range may not be in the best concentration, which is why caution should be used. Well documented occurrences or attacks/movements that are consistently imperceptible and have multiple witnesses can have the above methodology applied to them. Attacks that are shown as invisible to both character in the fiction and the actual readers could also be considered as candidates for this. Characters using actual leg strength for this feet will have peak kicking speeds > the speed they attained in doing it.

 Also to be considered is that while human levels are appropriate as a base minimum for this, reaction times of the characters start to become important when calcing this. For example: A character who dodges a handgun bullet from a 10 centimeters may have reactions of >3402th of a second. This means that they can surely perceive that length of time to react during it. This starts becoming important once their reaction time exceeds human time perception, so this is where reaction times take over for measuring this type of feat.

 So no. Faster than an eye can percieve does NOT mean we can percieve things moving just under light speed. If a baseball went by your head at mach four, you wouldn't have ANY idea what happened. You'd feel it pass you more than you saw it. So Lurk moar troll harder. GG no re.