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Saturday, October 1, 2011

ISO Settings - Meaning and Use

Many of us like to take photos with a digital camera. There are variety of settings that we can do to take a better photo. I am writing about ISO settings in this Blog Post.

Now a days most of us use Digital Camera. Still if you remember, with old film cameras you might have seen the numbers 100,200, 400 on the films(camera rolls). So what was that? It was ISO of that particular film.

In the digital camera, we still have ISO settings in a Manual Mode or an Auto ISO setting in the Auto Mode.

What is ISO?
ISO is the sensitivity of the image sensor (film in film cameras) of your camera to light. The lower the ISO number, less is sensitivity of your camera to light, finer are the grains in the photo.

With higher ISO numbers you can achieve faster shutter speeds* in low light conditions but with the penalty of less fine grains in the photo.
* Shutter Speed is the exposure time. I will illustrate this in next blog post.
Example -  I have added two photos. First photo has ISO 80 and the second photo has ISO 800. As you can see second photo is grainy but first is not. This will help you understand ISO better.




Most of the Digital Cameras allow ISO ranging from 80 to 800 or 1600. Auto mode adjusts the ISO automatically with changing light conditions.

If you want to change the ISO settings manually, you need to consider following conditions -

1. Light - How is the light on the object. If you have a bright light conditions, you can keep the ISO low to get photos with finer grains.

2. Grain – If you want a grainy shot, you can have higher ISO numbers, Otherwise you will need to keep them low.

3. Tripod or Hand held Camera – If you are using tripod, you can take photos even with lower shutter speeds without any problem, But if you are holding the camera in hand then you will want faster shutter speeds to take the picture. So with tripod, you can have lower ISO, otherwise you will require higher ISO.  

4. Moving Subject –If your subject is moving (a flying bird, running animal, sportsman) then to catch a clear photo, you will require faster shutter speed, hence higher ISO. With stationary objects, you can go for lower ISO.



There are many other factors to consider, but for time being these 4 are enough. You might need to combine the multiple factors at a time. eg. You have a bright light, object is moving, you dont have a tripod.

So experiment with different ISO settings and see how they impact your photos.

Take more and more photos! Enjoy Photography! :-)