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Shutter Speed

Shutter Speed:

The amount of time that a camera shutter stays open; thus requlating how long the film is exposed to light.

The shutter speed of a camera is typically messured in fractions of seconds, 1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000. Likewise the shutter speed may also be notated as 1, 2, 4, 8, 15, 30, 60, 125, 250, 500, 1000; with 1 being equal to 1 second and 1000 being equal to 1/1000 of a second.

Note:

TV's and most monitors refresh there screens every 1/60th of a second. Therefore, when shooting a TV or monitor you should use a shutter speed of 1/60.

Aperture

Aperture:

The opening of a lens which regulates the amount of light which enters the camera body.

A camera lens is very similar to the human eye. Much like the pupil of a human eye, the size of a lens aperture may be adjusted to allow more or less light into the camera.

The camera lens aperture is messured in f-stops which include f-1, f-1.4, f-2, f-2.8, f-4, f-5.6, f-8, f-11, f-16, f-22, f-32. The larger the f stop, the smaller the aperture opening and thus the less light it allows into the camera. The f-stop number is calculated by taking the focal lenght and dividing it by the diameter of the aperture opening.

f-stop = F/A

F = Focal Length

A = Diameter of Aperture Opening

Lenes with large maximum apertures are refered to as fast lenes as they allow alot of light into the camera; therefore they may be used at higher shutter speeds.

Exposure

Exposure value (EV):

The amount of light hitting the surface of the film.

The exposure value is equal to the aperture times the shutter speed. The shutter speed is directly proportional to the aperture; therefore, if the aperture is increased by 1 full f-stop the shuter speed will need to be decreased by one full step to keep the same exposure value.

EV = f-stop x t

f-stop = Aperture f-stop

t = Shuter Speed

		f-1	f-1.4	f-2	f-2.8	f-4	f-5.6	f-8	f-11	f-16	f-22	f-32
	1sec.	0	1	2	3	4	5	6	7	8	9	10
	1/2sec.	1	2	3	4	5	6	7	8	9	10	11
	1/4sec.	2	3	4	5	6	7	8	9	10	11	12
	1/8sec.	3	4	5	6	7	8	9	10	11	12	13
	1/15sec.	4	5	6	7	8	9	10	11	12	13	14
	1/30sec.	5	6	7	8	9	10	11	12	13	14	15
	1/60sec.	6	7	8	9	10	11	12	13	14	15	16
	1/125sec.	7	8	9	10	11	12	13	14	15	16	17
	1/250sec.	8	9	10	11	12	13	14	15	16	17	18
	1/500sec.	9	10	11	12	13	14	15	16	17	18	19
	1/1000sec.	10	11	12	13	14	15	16	17	18	19	20

General Exposure Values

EV 15 - direct sunlight.

EV 12 - open shade on a sunny day.

EV 7 - typical indoor lighting in offices, etc.

The exposure value can also be calculated using the following formula.

EV = log2(A² x (1/t))

A = Aperture Diameter

t = Shutter Speed.