exam q-1

[mysteryscribe]

This is your final exam on exposure...Nothing but exposure

1-Why is a sheet of film (digital sensor) like a bucket.

 

[elsaspet]

Dude, when do you sleep?????

 

[mysteryscribe]

I'm trying not to....So answer the questin chick.... lol

 

[Johnboy2978]

I'll play.
Photography is the exposure of light. You can think of an exposure like an empty bucket that you wish to fill with water. There are many factors that influence the rate at which the bucket is filled (or under filled or over filled). One factor which influences the amount of light that 'fills' the negative, slide, or sensor would is the ISO setting on a digital camera or the film speed on a film camera. The lower the rating, the less sensitive it is to light, and thus, the longer it takes to properly expose it.

Similarly, aperture also influences the rate. A large aperture (small opening) like f/22 restricts the diaphram thus allowing a small amount of light to strike the sensor, or in the analogy, filling the bucket slowly. A small aperture (large opening) like f/1.8 dialates that diaphram thus allowing a large amount of light to strike the sensor/film (fills the bucket quickly).

Finally, the shutter speed influences the rate. A high shutter speed (1/8000) would let a very small amount of light to hit the sensor while a slow shutter speed (1/8 ) keeps the shutter open longer allowing more light to expose the film. These three factors work in conjunction to expose the film/sensor to create a properly exposed image. A byproduct of a fast shutter speed is that it 'freezes' the action (i.e., sports photography) while a slow shutter speed tends to have a blurring effect of motion (e.g. creating a 'wispy' effect on a water fall)

These factors can be similarly manipulated to either creatively under/over expose the image. Hence, the film/sensor is analogous to filling an empty bucket with water.

How's that for someone who has never taken a photography class/read a photography book? Do I pass?

 

[mysteryscribe]

To begin with iso is the size of the bucket lol

Otherwise you seem to have the concept pretty well.

To keep it simple a bucket and a piece of film/sensor share the ability to be filled, paritially fillied, and over filled.

A partially filled bucket is generally not a good thing, and overfilled bucket is hard to work with but (up to a point) can be used if handled very carefully.

To get a correctly filled bucket you need the right combination of volume and time. You can vary either if you vary the other. the various choices can be charted just as a light meter does. The chart (ie light meter) gives you choices of time and volume combination.

Why you choose which combination is another lesson lol.

Pure correct exposure is any of the possible combinations.

Does that sound about right?

 

[Johnboy2978]

To begin with iso is the size of the bucket lol

Then that would imply that an image taken with ISO 100 film would contain more information then one taken with ISO 800 film (or vise versa). This isn't the case though is it? You will add grain with higher speed film, but will the amount of information change?

 

[mysteryscribe]

No the amount of time and volume to get the correct exposure will change. Ie the size of the container to be filled volume in this case is not information but just the amount of light to fill the container.

 

[mysteryscribe]

I should say if this is boring I won't do any more.... I don't want to just throw stuff at people who already know it. That is boring as hell Im sure

 

[Torus34]

As an aside, large astronomical telescopes are called 'light buckets.'