Why are exposure times so long if light travels so fast?

[runnah]

bump

@$$hole!

 

[Light Guru]

I'm still having trouble with understanding the "blur" thing, but I guess I'm gonna have to do some research. I don't get how "movement" can be captured into a final image if a camera captures something at an instant in time. Obviously a "blur" shows movement.

For example, a person running across the image and then the final image has him or her in 4 different places at once (as various blurs of course). I don't get how that can happen really. It's boggling my mind!

The camera DOES NOT capture the final image in an instant. It is gathering light the ENTIRE time the shutter is open. If the shutter speed is 1/100sec it is capturing light for 1/100sec if the shutter is open for 30 seconds it is capturing light for the entire 30 seconds.

As for your example the person is NOT in 4 different places at once the person was in ALL of the places from the start to the end of the blur. You would only see the person in 4 places if they stopped and stood still in 4 different places through out the course of the exposure.

Again the camera DOES NOT capture the final image in an instant. It is gathering light the ENTIRE time the shutter is open. This is why its the amount of light NOT the speed of light that matters when exposing your image.

 

[pixmedic]

I'm still having trouble with understanding the "blur" thing, but I guess I'm gonna have to do some research. I don't get how "movement" can be captured into a final image if a camera captures something at an instant in time. Obviously a "blur" shows movement.

For example, a person running across the image and then the final image has him or her in 4 different places at once (as various blurs of course). I don't get how that can happen really. It's boggling my mind!

The camera DOES NOT capture the final image in an instant. It is gathering light the ENTIRE time the shutter is open. If the shutter speed is 1/100sec it is capturing light for 1/100sec if the shutter is open for 30 seconds it is capturing light for the entire 30 seconds.

As for your example the person is NOT in 4 different places at once the person was in ALL of the places from the start to the end of the blur. You would only see the person in 4 places if they stopped and stood still in 4 different places through out the course of the exposure.

Again the camera DOES NOT capture the final image in an instant. It is gathering light the ENTIRE time the shutter is open. This is why its the amount of light NOT the speed of light that matters when exposing your image.

What would happen if you were traveling at the speed of light when you took the picture?

 

[Light Guru]

What would happen if you were traveling at the speed of light when you took the picture?

Depends on the shutter speed. If we could have a shutter speed fast enough your movement would be captured just like how we capture a runner in a photo now.

 

[photoguy99]

I'm still having trouble with understanding the "blur" thing, but I guess I'm gonna have to do some research. I don't get how "movement" can be captured into a final image if a camera captures something at an instant in time. Obviously a "blur" shows movement.

For example, a person running across the image and then the final image has him or her in 4 different places at once (as various blurs of course). I don't get how that can happen really. It's boggling my mind!

The camera DOES NOT capture the final image in an instant. It is gathering light the ENTIRE time the shutter is open. If the shutter speed is 1/100sec it is capturing light for 1/100sec if the shutter is open for 30 seconds it is capturing light for the entire 30 seconds.

As for your example the person is NOT in 4 different places at once the person was in ALL of the places from the start to the end of the blur. You would only see the person in 4 places if they stopped and stood still in 4 different places through out the course of the exposure.

Again the camera DOES NOT capture the final image in an instant. It is gathering light the ENTIRE time the shutter is open. This is why its the amount of light NOT the speed of light that matters when exposing your image.

What would happen if you were traveling at the speed of light when you took the picture?

For starters your camera would be extremely heavy

 

[pgriz]

What would happen if you were traveling at the speed of light when you took the picture?

Well, assuming we could do the impossible (which is to accelerate matter to the speed of light), you'll find that "time" now stops,and any time-related attribute becomes meaningless. This comes from the observation that time as perceived by the traveller who is accelerating to faster and faster speeds becomes slower and slower.
See: Time Dilation - How time isn't the contant it seems to be for discussion of this phenomenon.

 

[photoguy99]

On the up side, shutter speed hardly matters as things outside your reference frame will be frozen still.

You better have great panning technique, though.

 

[petrochemist118 143]

What would happen if you were traveling at the speed of light when you took the picture?

Speeds are all relative. From the point of view of a photon travelling towards you, you are travelling at the speed of light!

Getting something with mass to approach something else with mass at the speed of light will require infinite energy. Getting close to the speed of light is theoretically possible but time gets complicated above ~0.98c.

 

[480sparky41 40]

What would happen if you were traveling at the speed of light when you took the picture?

Do you need to turn on your headlights for that?

 

[DrDave]

At the speed of light, electromagnetic resonance would approach critical mass inversely proportional to the photons resonating frequency which would then allow you to photograph infinity!

 

[robbins.photo]

What would happen if you were traveling at the speed of light when you took the picture?

It would depend entirely on whether your windows were rolled up, or down of course.

Physics!

Lol

 

[Braineack]

sometimes i think scientists make up rules/law that explain things like the inability to travel at the speed of light, with long math formuals that no one really can understand just as a way to prove things we dont understand.

 

[Fire]

Im amazed at how many responses there is! You guys rock!

 

[snowbear116 47]

Im amazed at how many responses there is! You guys rock!

Boredom

 

[TCampbell]

What would happen if you were traveling at the speed of light when you took the picture?

Well, assuming we could do the impossible (which is to accelerate matter to the speed of light), you'll find that "time" now stops,and any time-related attribute becomes meaningless. This comes from the observation that time as perceived by the traveller who is accelerating to faster and faster speeds becomes slower and slower.
See: Time Dilation - How time isn't the contant it seems to be for discussion of this phenomenon.

^^ This

It isn't just that it's just not possible to travel faster than the speed of light. We can't actually travel at the speed of light.

If you could truly reach the speed of light, time would stop completely. If you pick on a star in the Andromeda galaxy (nearly 3 million light years away... which means traveling "at the speed of light" it takes 3 million years for it's light to reach us) and take the point of view of a single photon of light... time has "stopped" for that photon. The light from those distant stars is simultaneously released from the star AND absorbed by your eye... at the same time. From that perspective of that photon, it's speed did not change... rather the distance in space compressed to nothing. But keep in mind that's from the point of view of the "photon" of light. To us, that journey took nearly 3 million years and space was not compressed.

Here's a pretty good video which explains both special and general relatively with some great examples.



And while it all seems impossible and crazy, there are not only experiments and observations to confirm it's accuracy, we take many every-day technologies for granted which RELY on this theory in order to work at all (if they didn't account for it, they wouldn't function... GPS devices are a great example.)