WHAT ABOUT APERTURE AND ISO? by

WHAT ABOUT APERTURE AND ISO? by
WHAT ABOUT APERTURE AND ISO?
by
Dick Kenyon
Exposure is determined by:
> Aperture
> ISO
> Shutter speed
Aperture Number vs. Amount of Light
The aperture is the opening in a lens diaphragm that admits light to the
sensor.
Think of the aperture as an upside down window shade.
The higher the shade is up, the less light is admitted. The larger the aperture
number, the less light falls on the camera's sensor
The lower the shade, more light is admitted. The lower the aperture number,
the more light falls on the camera's sensor
Higher shade =
Lower shade =
Less light =
More light =
Higher f number
Lower f number
Large Aperture = Large Diaphragm Opening
Ex. f/2.8
Small Aperture = Small Diaphragm Opening
Ex. f/16
Aperture and Depth-of-Field
> Lower aperture number = less depth-of-field
> Higher aperture number = more depth-of-field
© Dick Kenyon
f/16 to get good depth of field
© Gale Kenyon
f/3.5 to blur background
f-Stop Defined
> An f-stop is the is the difference between f-numbers on the standard f-stop scale.
> For example the difference between f/2.8 and f/4 or between f/8 and f/11 is one fstop.
> Moving from one aperture to a higher aperture by one stop cuts the admitted light
by one half. i.e. f//8 to f/11
> Moving from one aperture to the next lower aperture, one stop, doubles the
admitted light. i.e. f/11 to f/8
F Stop Scales
Standard full-stop f-number scale
Including aperture value AV:
AV -2 -1 0 1 2
f/# 0.5 0.7 1.0 1.4 2
3 4
2.8 4
5 6
5.6 8
Typical one-half-stop f-number scale
f/# 1.0 1.2 1.4 1.7 2 2.4 2.8 3.3 4
7 8 9 10 11 12 13 14
11 16 22 32 45 64 90 128
4.8 5.6 6.7 8
Typical one-third-stop f-number scale
f/# 1.0 1.1 1.2 1.4 1.6 1.8 2 2.2 2.5 2.8 3.2 3.5 4
10 11 13 14 16 18 20 22
Typical one-quarter-stop f-number scale[2]
f/# 1.8 2 2.2 2.4 2.6 2.8 3.2 3.4 3.7 4
9.5 11 13 16 19 22
4.5 5.0 5.6 6.3 7.1 8
4.4 4.8 5.2 5.6 6.
9
Adjustment of Aperture on Camera
> Control of Aperture is via a camera body wheel or other control device.
> The aperture value appears as a readout on the LCD display and in the
viewfinder if the camera has a viewfinder.
> Depending on the camera, the Aperture may be adjusted in 1/3 stops or ½
stops.
> To keep exposure the same for a given ISO if the aperture is reduced by
one stop the shutter speed must be increased by one stop and vice versa.
Example: f/11 and 1/125 sec is equivalent to f/8 and 1/250 sec
ISO
> ISO is a number that represents the light sensitivity of the camera's sensor.
> Higher ISO = Higher Sensitivity to Light
> Lower ISO = Lower Sensitivity to Light
> ISO values generally range from about 80 – 1600
> Higher ISO = Higher noise in image
> Newer, digital cameras, with excellent noise suppression software, can
operate with an equivalent of 12800 ISO
> BEST TO SHOOT AT LOWEST ISO POSSIBLE
> WISE TO CHECK ISO AT START OF EACH SHOOTING SESSION!
APERTURE PRIORITY, SHUTTER PRIORITY, MANUAL
SHOOTING MODES
> Aperture Priority Mode – Use when you need control of aperture.
You set the aperture, the camera sets the shutter speed for
proper exposure. Control of aperture determines depth of
field.
> Shutter Priority Mode – Use when you need control of shutter
speed. You set shutter speed, camera sets aperture for proper
exposure. Choose high shutter spped to freeze motion, slow
shutter speed to blur motion
> Manual Mode – In manual mode you set both aperture and shutter
speed. You also control ISO. You get ultimate control of functions
determining exposure and maximize your creative capability.
Aperture References:
http:www.shortcourses.com/use/using1-9.html
http://www.digicamhelp.com/camera-features/advanced-settings/aperture/
ISO References:
http://www.digicamhelp.com/camera-features/advanced-settings/iso/
http://www.photoxels.com/tutorial_iso.html
http://www.digital-photography-school.com/iso-settings
http://w
The End
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertising