Wednesday, March 30, 2011

Back to Basics 1 ISO

It has been so long since I last post. To the very few people that DO read my rants, I do apologize but I have been busy as most people. I do have a day job - unpaid as it is, it is still a job. Lots have been on my mind and I really needed a break, so here I am blogging again. This is also a landmark post, it is the first of many from my new Macbook Pro (pressie from my beautiful fiancee - yay for me!).

As the world is ending soon...apparently it will start on May 21st and finish in Dec, how I dont know, but I thought it would be a great idea to start talking to those of ya who would like to learn about photography but are scared to ask simple questions...yes you noobs... its ok to be a noob!...we have to start somewhere.

Today's lesson is ISO.

Firstly, I think that a well exposed images is controlled collectively by three variables. ISO, aperture and shutter speed.

what is ISO?

No it is not ISO horny... or ISO lub u long time... (bad joke i know...)

ISO stands for International Organization for Standardization.

Instead of telling you how it was really derived and how the organization decided on the standardization, I think the most important thing is to understand, what does ISO mean to me?

ISO is basically how sensitive the sensor of your camera or the film you are using to light.
- more sensitive the sensor is to light.
- less light required to expose an image.
- if using digital, the more noise (usually undesired) - many basic cameras tend to produce unpleasant photos above ISO 800.
- if using film, higher ISO may give nicer grain, which can be desirable depending on the style of photography. eg. many street shooters use ISO 400 whereas landscapers use ISO 50 film.

- slower shutter speeds (can be desirable in certain creative situations).
- finer detail in the photos, usually higher quality photos.

So what do I do with ISO? Generally I try to shoot with the lowest ISO possible to obtain the highest quality photos. I will increase ISO generally up to a maximum of ISO 400 if the shooting conditions are too dark.

So, thought process generally is:
1) Set ISO low unless subject/shooting environment is too dark.
2) Set aperture to express creative control. (we will cover what changing the aperture does in a future blog).
3) Set shutter speed to carefully expose image. or if using Av mode, let the camera decide shutter speed. But if this is the case, make sure you check that the shutter speed is not too slow or you will risk camera shake.
4) If image is still has shake, then increase ISO until you find a shutter speed that will allow you to hand hold.

An alternative situation could be, if using a higher ISO such as 200 on a bright sunny day, all of your shots may be very static, due to high shutter speeds, but even at the smallest aperture your shutter speed might still be 1/200 so what do you do?
1) decrease the ISO to 100 or 50 and check your exposure. the shutter speed should have dropped, allowing you to use a slower shutter speed and thus allowing you to introduce motion into the scene.

There are also other techniques of introducing motion, but will be covered at a later stage.

I hope this information is helpful. I havent included any photos to show examples cos all you would see is bright and dark photos so it is not much use! so just get out there and try playing around with your ISO.

Till next time. Take care.

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