shutter speed 1/focallength rule Link to heading

how to choose shutter speed to shoot an acceptable sharp photo?

follow focal length rule.

say you have a 50 mm lens, shutter speed should less or equals to 1/50

x-sync speed(1/250 - 1/500): the fast time fisrt curtain open completely and expose the whole sensor

set shutter speed to x-sync, no quicker(eg. 1/1000 there will be bans). when you have a flask unit.

stop for shutter speed Link to heading

1 / 30 is one stop away from 1 / 60

how crop factor affects shutter speed rule Link to heading

APS-C sensor in relation with full frame sensor

  • for Nikon focal length x 1.5 (35mm lens ~ 50 mm equivalent lens in full frame sensor)

  • for Canon focal length x 1.6

according to equivalent focal length, you can calculate the equivalent shutter speed.

ISO Link to heading

measures sensitivity to light

  • higher ISO = more noise = quicker shutter speed

    2 x ISO = 1 / (2 x orig. focal length)

  • smaller sensor = more noise

  • use the lowest ISO whenever possible

  • Auto ISO is great when low light

stop for ISO Link to heading

iso 125 is one stop darker than iso 250

Apecture Link to heading

f number Link to heading

f-number

  • f-number = focal length / Diameter

\( Apecture size = \pi \times ({D \over 2})^2 \)

according above equation, so 1 stop difference is

f/1 <—> one stop <—> f/1.4(sqrt(2)) <—> f/2 ……

exposure-triangle

metering Link to heading

partial metering

spot metering

problems with metering Link to heading

it works fine when we have balanced light, but when the light is narrowed, it will be a problem, see below to use different types of metering to avoid.

nikon matrix/evaluative metering(landscape) Link to heading

on most DSLR’s

center weighted metering(portrait) Link to heading

ignore corner’s light, focus on middle

  • capture a man with the sun behind

spot metering(pinpoint one item) Link to heading

focus on focus point and ignore other light

  • capture a small animal
  • shoot the moon

lens filter Link to heading

enhance colors and reduce reflections

most popular size is 77mm

uv/clear/haze filter Link to heading

make photo clean. modern digital camera have uv filter installed in front of sensor

polarizing filter Link to heading

  • linear polarizing filter is not for DSLR(metering problem)
  • circular polarizing filter is for DSLR

good for landscape, waterfall.

maxium polarizations is 90 degree from the sun

using polarizing filter may lose 2 stops.

should not be stacked with other filters.

materials: glass vs. resin Link to heading

nutural density filter (ND) Link to heading

reduce light, convinient during the day.

Graduated ND filter Link to heading

half clear, good for horizon

hard-edge GND filter Link to heading

good for mountain

reverse GND filter Link to heading

good for sunset

color warming/ cooling filter Link to heading

seldom used

colsed up filter Link to heading

special effects filter Link to heading

step-up rings vs. step-down rings Link to heading

Step-down rings can cause vignetting and other problems, so always try to use step-up rings instead

white balance Link to heading

color temperature Link to heading

measuring the white areas - increases blue channels

  • dayly light - for afternoon

setting custom white balance Link to heading

white or grey(80% grey) card

  1. set auto white balance
  2. place grey card in front of the subject
  3. switch to manual focus
  4. take a photo
  5. navigate to custom white balance
  6. choose the correct card picture
  7. select ok

MLU & bracketing Link to heading

bright sunny day combo Link to heading

  • S: 1/100
  • ISO: 100
  • A: f/16

mirror lock up Link to heading

lock up the mirror in order to avoid vibration because of the mirror.

bracketing Link to heading

take various exposures at the same scene.

guide number Link to heading

guide number = f number * distance (ISO 100)

knowing guide number and distance, we can determine f number.

further and further it is difficult to use the equation because of inverse law

reduce red eye Link to heading

move flash unit up a little bit.

perspective Link to heading

perspective is determined by the relative distance between objects

transfroming ordinary to extraordinary