Thursday, 14 June 2012

ISO Setting/Film Speed

Hello! Today I'm going to talk about ISO, as it is known on digital cameras, or film speed, what it used to be called back in the days of 35mm film cameras. Hopefully after this article you can control your camera a little more manually, and take the next step in mastering your tool of work!

ISO or film speed is practically the sensitivity of your sensor or film to the light. The higher your ISO, the more sensitive the sensor or the film will be to light! On a digital camera, you can change this setting quite easily by going through the menus (find exactly how too in your specific camera manual), however on a film camera, the film speed is on the film you buy, so if you buy ISO 400 film, you've got a Film Speed of 400 until you switch to a new roll of film, with a different ISO.

ISO numbers go up in a rather standard order, starting with the lowest number, the ISO setting that gives the lowest sensitivity to light, here is a typical scale; 100, 200, 400, 800, 1600, 3200, 6400.  This scale is the most common, but you can get odd numbers, the main thing to remember is 100 gives a very low sensitivity to light, 6400 would give you a very high sensitivity to light. These numbers, on more modern, higher end cameras have been extended, like the new Nikon D4, the peak of tech at the moment, has an expandable ISO of 50-204,800.  That is one crazy range, and it's only going to get better as technology progresses.

Well if you can change a sensors sensitivity, why can't we use a really high ISO and take photos in the dark, without having to increase our shutter speed? Grain, Or noise as it is known on a digital camera. The higher your ISO, the more grain you will get, for example, look at this shot, taken at 6400 with no noise reduction;
Now this is a particularly bad example of lots of noise, because my camera is known for bad high ISO performance, but if you go to an ISO of 1600 or more, you are going to start noticing image compromising noise, so look out for it when taking a photo.

So, for my conclusion, here is my ISO scale, All these photos were taken at an F-stop of f/5.6 and an exposure time of 1/10th of a second, with the ISO used under each photo.

ISO 100
ISO 200
ISO 400

ISO 800
ISO 1600

So that's all for today, the last tip I can give you, is experiment with your ISO, sometimes, noise/grain is desirable, such as in certain black and white images, or giving an image that "retro" feel.

Anything else you want to know? have any ideas or suggestions? Knock em down below, and as always, Happy photographing!


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