Photography Notes

The three elements of exposure in photography -Basics!!

• ISO
• Shutter Speed
• Aperture

ISO: The sensivity of the film to the light.

• The lower the number the finer is the grain of the shot
• Choosing a lower ISO will mean that your camera’s sensor is less sensitive to light and will need the shutter to be open longer. It will also mean less ‘noisy’ or grainy shots which will give your shots lots of nice detail.

ISO 100 —great image quality however needs light
ISO 200: Overcast days
ISO 400: indoor, sports action

Shuter speed: The amount of time the shuter is open to the light.

• Shuter speed is measuerd in the fraction of seconds the lower the denominator the faster is the speed of the shutter (e.g 1/800 is faster than 1/30).
• The slowest speed we can genearally use is 1/60 seconds because lower than this the camera will start shaking causing blur pictures (ah! now i know why I have those pics so blurry!)
• We have to consider the focal length while choosing a shuter speed.The ‘rule’ of thumb to is to choose a shutter speed with a denominator that is larger than the focal length of the lens. For example if you have a lens that is 50mm 1/60th is probably ok but if you have a 200mm lens you’ll probably want to shoot at around 1/250.

Aperture: The size of the opening of the lens when taking the picture.

Aperture is measured in ‘f-stops’.  example f/2.8, f/4, f/5.6,f/8,f/22 etc.

• When we move from one f-stop to next it  doubles or halves the size of the amount of opening in the lens 
• A change in shutter speed from one stop to the next doubles or halves the amount of light that gets in.
• One very confusing point is if the f- stop is smaller it means that the apperture size is larger causing more light to get through . Larger apperture are given smaller f-stop number.e.g. f/2.8 is in fact a much larger aperture than f/22.
• Changing the apperture will also affect teh depth of field. The smaller apperture will cause larger depth which means that all part of your subject is in focus. Larger appreture will result in smaller depth of the color resulting in only the part of the subject in focus.

 

Handy in Potrait photography : The apperture should be larger( smaller the f-stop number) resulting in a blurry backgroud.

 

  Tips on potrait potography:

What format to use when taking potrait photographs:
Verical : when you want the picture to come out as posed and formal.
Horizontal: this framing will come out as a little informal and will be handy when we want to place the subject off-center and have a nice out of focus (flowing) background behind the subject.

 

A few things to remember; 1) For me. . it was easier to learn how the “creative modes” (Av, Tv, M) performed, than it was to learn what the “basic modes” (portrait, sports) performed.

2) In the creative modes, the camera is not mistake proof. If you try to take a day exposure for 6 seconds with a wide open shutter and nothing in focus. . .the camera will let you do that.

3) Learn the relationship between aperture, shutter and ISO. You need to set two parameters, and let the camera solve for the final element using the built in light meter.

You always set the ISO manually (100, 200, 400), controlling quality. Sometimes, you will find that you need to increase ISO to allow the camera to calculate a reasonable shutter/aperture value.

In Av mode (aperture value mode), you set aperture and ISO and the camera picks shutter speed.

In Tv mode (time value mode), you set shutter and ISO and the camera picks ISO.

In M mode (manual), you set all three parameters and the camera meter readings are ignored.

Smaller aperture value implies greater depth of field, but more light will be required to expose the image (higher ISO and longer shutter). Remember the 1/f rule (if you have a 100mm lens setting, any image with a shutter slower than 1/100th second will show motion blur)

Once you learn this. . .everything follows.

4) And it is rare to ever have enough light. Seems like you can never take a F8 image with 1/500th shutter speed at ISO 100. The flash unit is a friend, but a high maintenance friend (takes alot to make it work well)