What are they and why would I change the ISO settings?

What are ISO camera settings and what does ISO mean? ISO stands for International Standards Organisation and it refers to the industry norm for sensitivity of emulsion based film, with 100 ISO being not so sensitive (and the standard ISO used by most people) to 1600 ISO which is extremely sensitive to light.

The major headache with film photography was that if you wanted to change the ISO settings, you had to change the film itself! Not good if you were in a hurry. There was a way to "push" the film by underexposing it to get faster shutter speeds, and sorting out the mess in the darkroom later, but you still had to "push" the entire film.

The beauty of digital, and I have found myself changing ISO settings so much more often now, is that you can alter the ISO for each individual shot. This means, should you come across a situation where you are in low light and cannot use flash, you can just up the ISO settings to 800, 1600 or even 3200 making the sensor a lot more sensitive to light, and fire away knowing the images will come out ok.

If you get in a situation where you have the aperture fully open and the shutter speed selected is too slow to hand hold such as 30th or 15th/sec, use the higher ISO settings, they are like a Godsend in digital photography, especially if you don't carry a flashgun.

The opposite is true here as well. Where high ISO's give grainier, lesser quality images, a low ISO such as 100 or 50 will produce the finest quality, grain free images that your camera is capable of. This is worth remembering if you are doing important work with your digital SLR. The Kodak Pro series of digital cameras go as low as ISO 6!!! Imagine the quality there!

With film, anything above ISO 400 would produce grainy and textured images and the techniques in the 80's and 90's for reducing grain were few and far between. However, with the new breed of digital cameras such as the almost "grain free" Canon EOS 20D, 30D, 40D and amazing Canon EOS 5D, the "noise" as it is also known, is barely noticeable in some images.

Even if a bit of grain or noise does appear, there are programs such as Neat image available that will all but remove any signs of grain...amazing!

If you own a digital SLR, play with these ISO settings to see how it can improve your photography. Purposely leave your flash at home and turn the ISO settings right up to see how it functions. Heavy grain in some images such as buildings or landscapes can really add great, moody effects to your shots.

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