Photo Talk - Lesson 3 - ISO

Alrighty...we're back! Now that we've covered the basics of composition, we're getting into the mechanics. I'm a firm believer that until you can shoot comfortably in fully manual mode, you're not a true photographer. You must know how your camera works and be able to manipulate the settings for the light that you're in.

Don't worry, we'll be going really slow for a while.

ISO denotes "film" speed. Remember when you bought film way back in the old days? They had numbers on them. 100, 200, 400, and 800 were the standards for the average picture taker. 25, 50, 1600 and 3200 were (are) also available if you knew where go.

Now stay with me, this is good to know. Film is coated in grains of silver. The silver absorbs the light entering the camera, which creates the image. (This has been replaced with a digital plate in digital cameras.) Film with a low ISO (25, 50, 100) has super fine grain and it is slower to absorb, so it needs more light. That's why those film boxes would say to only use ISO 100 in bright sunlight. The upside is the picture turns out very clear and crisp even when enlarged.

Most point and shoot cameras have a low ISO setting as the auto setting.

Film with a high ISO (800, 1600) has large, course grain and absorbs the light faster so it's great for low light situations like night time or times when you don't want to use a flash (like concerts or recitals). However, your image will have "grain" or "noise" (the digital word). It won't have that super clear, crisp look of a low ISO. You have to decide if the trade off is worth it.

Okay. Go get your manuals and see if you can change your ISO on your camera. If you can I want you to practice shooting with it low and high in different lighting situations.

If you have a "P" function on your camera (many have P, Av or A, Tv or S, and M as settings). So if you have a P, set your camera there. Then change your ISO, then shoot. The camera will set the other important settings (shutter speed and f/stop) for you as long as it's in P. But you will be able to change your ISO.

Remember low ISO needs lots of light and will be clear. High ISO requires less light and will be grainy.

A couple examples.

Low ISO...bright sunshine, nice and clear.



High ISO...the only source of light in this picture was the fireworks off in the distance. The grain isn't bad because the good digital SLR's tend to have very little noise/grain even in the higher ISO.



Here's another because I want you to see a more realistic grain. This was in the old days. It was taken with 3200 ISO film. No flash, on a football field at night.



Now for what digital grain on a point and shoot is likely to look like. 1600, no flash in a karate studio.



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