Numbers to know
- T-shutter speed 快門
- A-Aperture 光圈
- Lens focal length 焦距
- ISO- film sensitivity
- Image size & format
Lens focal length 焦距
- fish-eye (6-13mm) 魚眼
- Superwide (13-24mm)
- Wide (28-35mm)
- (Human eye 50mm=40-60degree)
- Macro lens 100mm微距/ 人像
- Tele 200-500mm
- Mirror reflex lens 300-500mm 波波鏡
- compact camera1.5-1.6 x crop factor
- Fish eye
- Mirror reflex-波波鏡
exposure
- EXPOSURE 18% grayness (midtone zone V)
- Zone system
- system of exposure calculated by Ansel Adams
- -eleven zones of brightness image
- -zone 0- solid black
- zone 10- pure white
- Exposure value( EV)= combination of exposure time and aperture
- exposure compensation snow +1
- dark subject -1
T-shutter speed快門
- b- 1/2000s
- Hand held 1/60 sec to avoid unsharpness
Taking photo inside a moving car 1/500sec
- 1/focal length for tele use 1/500 sec if using 500mm tele lens
- L
- APERTURE
- f-number(1 1.4 2.8 4 5.6 8 11 16 32)
- the fraction of the focal length of the lens
- F 2.8-narrow depth of Field-portrait
- Low light environment
- F 16 –widen depth of field for landscape
- Control exposure and depth of field
ISO value
- ISO 100 normal
- Increase 1S0 x 2 can decrease one EV (exposure value)
- 1/125 sec 8 ISO=100
- 1/60 sec 8 ISO =200
- 1/60 sec 11 ISO= 400
Image size & format
- Raw + jpeg highest
- Film= 25 x 30mm=0.984 x1.88 in 20 million pix
- Print need 300dpi (dot per inch)
- 12Rprint( 28 x 20.3cm) need 8million pix
- 16 x 20 inch for salon competition needs 29million pix if 300dpi
- Or 18 million pix if 200dpi
- Digital camera 5-20 MB
- Smart phone 1.5 MB
- Low resolution
Format ratio
F3:2(4Rprint)
4:3
16:9 aspect ratios(TV)
Need 72 dpi or width has 1900 pix for landscape format and height has 1200 pix for portrait format.
Hyperfocal distance
Focus 1/3 of the way between the foreground & background (required zone of sharpness), because at moderate distance, the DOF extends twice as far behind the subject as in front.
COMPOSITION
- rule of thirds三分法
- Dominant object & subordinate object
- object on one of the junction points.
FLASH SYNCHRONISTATION
- Slow synch- a burst of flash with
- longer shutter speed
- the flash light exposes main subject
- & background is exposed by ambient light with longer exposure
- Second curtain synchronization
- (rear-curtain sync/ trailing sync)
