Proper Exposure and ISO

Review What’s a histogram? What is it used for? How do you find it on your camera?

What does this histogram tell you?

What about this one

Or this one

Proper exposure What three controls on the camera control this? Where are they?

To get the correct exposure, you must balance time (shutter speed) with your aperture opening (f stop) with sensitivity of the sensor (ISO) Proper Exposure

1 - 4-element lens 2 - Reflex mirror 3 - Focal-plane shutter 4 - Sensor 5 - Matte focusing screen 6 - Condenser lens 7 - Pentaprism 8 - Eyepiece

FILM SPEED ISO/ASA -International Organization for Standardization(ISO) -Similar to ASA on manual film cameras - ISO indicates the sensitivity of the camera towards light. - The lower the ISO, less sensitive the sensor is to light, and the more “clean” an image. It requires more exposure to light than a higher ISO -The higher the ISO, the more sensitive the sensor is, and the more noise. You need less light to use higher ISO’s. - Set your ISO at the lowest possible setting you can for a higher quality image.

Question to ask yourself when choosing an ISO When choosing the ISO setting I generally ask myself the following four questions: Light – Is the subject well lit? Grain – Do I want a grainy shot or one without noise? Tripod – Am I using a tripod? Moving Subject – Is my subject moving or stationary? If there is plenty of light, I want little grain, I’m using a tripod and my subject is stationary I will generally use a pretty low ISO rating. If it’s dark, I purposely want grain, I don’t have a tripod and/or my subject is moving I might consider increasing the ISO as it will enable me to shoot with a faster shutter speed and still expose the shot well. Of course the trade off of this increase in ISO will be noisier shots. Situations where you might need to push ISO to higher settings include: Indoor Sports Events – where your subject is moving fast yet you may have limited light available. Concerts – also low in light and often ‘no-flash’ zones Art Galleries, Churches etc- many galleries have rules against using a flash and of course being indoors are not well lit. Birthday Parties – blowing out the candles in a dark room can give you a nice moody shot which would be ruined by a bright flash. Increasing the ISO can help capture the scene.

Noise- the cost of high ISO Basically, digital noise is random dark and light pixels that are out of color range for the area they are found in. Digital noise is caused when the sensor and camera electronics are just at the edge of being able to accurately assign color to pixels. Although there is some random digital noise throughout all digital images, high ISO ratings and low light is what puts digital camera sensors on the edge of being 'noisy‘.

ISO 100ISO 1600

There is HOPE! There are software programs that can significantly improve the quality of the digital images by reducing the objectionable noise. -Photoshop -Noise Ninja -and many more

Test the limits of your camera’s ISO. -go into areas that require you to increase your ISO in order to keep the shutter speed at 1/60 and above. Hands on Break!!