Beginning Photography Tips – Intro to ISO

ISO, otherwise known as film speed, is the foundation of the key elements of exposure. Your ISO setting determines how fast your digital sensor reacts to the light that hits it. The settings for both aperture and shutter speed are based on your sensor’s sensitivity to light.

ISO stands for–yep, you guessed it; International Organization for Standardization. Fortunately, we don’t need to remember this. For our purposes, “ISO” is just a short way of referring to film speed.

The Fast and Slow
Much like aperture and shutter speeds, there are different groupings for film speeds.

• Slow – ISO 50, 100, 200, 400
• Fast – ISO 600, 800, 1600, 3200

As with all things, there is a little bit of give and take when it comes to the speed of your film. Slower film requires more light, but typically yields cleaner and sharper results. Faster film requires less light, but starts introducing noise that may be undesirable.

Take Things Slowly
As you get more comfortable with your camera, you’ll start to realize that a slower film speed is desired because of the clarity it lends to your photos. It’s typically easy to use slow ISO settings on bright sunny days when there’s plenty of usable light.[ad name=”250×250″]

It’s not impossible to use slow film speeds indoors, on a cloudy day, or in studio settings. Since the film is slow to react to the light, this may require longer shutter speeds and wider apertures, so a tripod may be necessary at times to retain the sharpness of your photos.

The Need for Speed
Faster ISO settings are commonly used at night, indoors, or in low-light situations. Making the film/sensor highly sensitive to the light means that you can generally use faster shutter speeds. This is ideal if you don’t have access to a tripod or if you’re shooting indoor sports or quickly moving objects.

Let’s say you’re wanting to take some pictures at an indoor party, but you don’t want to use a flash. So, you set your ISO to 100, your aperture is wide open at f/4, and your shutter speed is at 1/60 sec. You take a picture and it’s blurry, so you bump up your film speed to ISO 200. This means your film is twice as sensitive to light now, which is equivalent to one stop of exposure. So, leaving your aperture wide open, you can take your shutter speed to 1/125 sec.

You take another picture, find that it’s a little better but not quite there, so you bump up your film speed yet again to ISO 400. This allows you to take your shutter speed to 1/250 sec which is a good speed for hand-held shots, so now you’re free to snap away! Sure, your pictures will have a little grainy noise in them, but a little grain is better than a lot of blur.

Here is a comparison of the same scene taken once at ISO 100 and then again at ISO 1600.

Make Some Noise!
Noise in photography isn’t necessarily a bad thing as it can be use creatively and artistically. The addition of noise is a common post-production technique to give a photo a vintage or edgy feel. The key here is that it’s easier to add noise than to eliminate it after the fact, so if you’re unsure then shoot at a slower film speed and add noise later on.

As digital technology continues to advance, the amount of noise that’s introduced at faster film speeds is decreasing. Not to mention the countless noise reduction programs available today that do a decent job of cutting down on the noise in your photos.