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# super high speed camera and laser ????

#### bobobob121

##### New member
climbak said:
but what about the minimal angle from the water?
i mean, the "entering" angle had NOTHING to do with the angle of light in the water :S
The angle is due to the different speeds in the different media. The equation describing this is Snell's Law:

n[sub]1[/sub]sin(theta[sub]1[/sub] = n[sub]2[/sub]sin(theta[sub]2[/sub]) where theta is the angle the ray of light makes with the line that is perpendicular to the surface.

The equation can be derived in many ways but I think in this case the best way to think about it is Fermat's Principle of Least Time which states that light will travel in a medium in such a way as to minimize the overall time it takes to go from point A to B. [/quote]

my brain hurts..stop it. lol ;D

#### climbak

##### New member
yeah, physics makes my head hurt a lot. I am in the wrong major.

#### nikokapo

##### 1
climbak, thank you, THAT was the answer i was looking for,

thank you again (+1rep for a good answer ;D).

you can go back on topic now haha

#### climbak

##### New member
I think someone who can bypass the physics should design a camera with a shutter made of light in a material whose phase speed is greater than c so we can have a faster shutter speed than c. definitely would have to be hi-def though haha.

#### diachi

##### Well-known member
: wow im looking forward to higher / adv higher physics ;D , but would that light shutter thing actually work ??

#### climbak

##### New member
haha not that i am aware of. maybe just use a mini black hole that can be turned on and off with alternating voltage. :

#### diachi

##### Well-known member
hmmm mini black hole ... well ill need some dark matter ... a strong magnetic field generator, and alot of luck

#### climbak

##### New member
maybe we can get a synchrotron radiation laser out of the deal too! what would we call it....

#### tone1132

##### New member
could you make a shutter out of lcd's that could take millions of frames per second? do digital cameras use shutters?

#### climbak

##### New member
digital cameras use a ccd chip; sometimes a cmos chip for the higher end camera. They have a shutter of some kind. I know the CCD at the Mt. Bigelow observatory here in Tucson, AZ has one since I've used it before. I think an lcd would be a way to make the shutter speed quite fast, but there are also other things to consider. It takes time for a ccd or cmos chip to readout the photons it has counted. the one on Mt. Bigelow takes up to about 5 minutes to redout depending on the resolution being used. I think this may be more of a limiting factor than shutter speed. I'm am not sure on that though, just what I think. I am also not sure on the technology behind the super fast speed cameras that are currently available.

L

#### likewhat

##### Guest
CCDs readout time is slow as hell, it is usually on the order of milliseconds. To take very fast pictures with shutter speeds of less than 1 nanosecond you have to use a microchannel plate or MCP as a shutter in front of your CCD or film. These can be gated such that they only amplify the incoming signal for the duration of the gate and otherwise they dont allow a signal to pass through them (optical signal, such as an image from a lens). If you have a subnanosecond gate pulse to the MCP then you get a subnanosecond picture. In order to make a video you use an array of MCPs that are gated sequentially. I put a link to a paper on one of these in my earlier post on this topic.