DSLR for Dummies- ISO

Let’s chat about ISO today.  Okay? Okay!

I first Googled ISO.  ISO stands for International Standards Organisation.  That’s helpful.

Nate………help!  SOS.  I’m falling asleep.

Nate informed me that ISO has to deal with shutter speed, lighting and “noise”.

In a DSLR camera, there is a sensor that receives the picture.  This sensor used to be film.  (Interesting.  I miss film.  Sort of.)  The invention of the digital camera was awesome for photography because previously your film determined your ISO.  Once you started a roll of film, you had to take all of your photos at that ISO.   Now we just do some button clicking magic and we have a new ISO whenever we want!

What exactly does ISO do?  ISO changes the light sensitivity of that sensor in the camera that is receiving the picture.

The lower the ISO, the less sensitive the sensor is to light.  The sensor gathers less light which may results in a longer time to take the photo (slower shutter speed).

How do you know determine what ISO to use?  Nate usually shoots in ISO ranges from 200-800.  He tells me that anything over 800 will result in more noticeable grain or “noise”.

So, why would you use anything over 800?  You are most concerned about ISO when you are in a low light setting.  In low light you will want a higher ISO because the higher ISO will give you a faster shutter speed.  The trade off with this faster shutter speed is the “noise”.
I asked Nate to give me some examples of situations and what ISO I should use…

High ISO:  An indoor basketball.  (There is probably poor lighting and that fast shutter speed will come in handy.)  Hand holding the camera at sunset.  (You will want the increased “noise” versus the blurry picture you will get with a low ISO.

Middle ISO:  Our house at night with the lights on/no natural light.  (He suggested ISO 800-1000)

Low ISO:  Outside on a sunny day.  Nature photography.  Sunset on a tripod.

The following photos are my ISO learning photos.  I am showing you my Picasa screen shot.  In the lower left corner, Picasa gives you the camera information.  Very helpful when writing these posts…

ISO 200  f/3.5  1/10s
ISO 400  f/3.5  1/15s
ISO 800  f/3.5  1/30s
ISO 1600  f/3.5  1/60s
ISO 3200  f/3.5  1/100s

What difference do you notice in the pictures?  (Other than the ISO 800 photo that is blurry due to operator error.)…..  Do you notice anything???..........I’ve got nothing.  It all looks the same to me.  Seriously Nate, are you just messing with me?

He first had me notice the shutter speed.  As you increase the ISO, the shutter speed increases.  I did notice this while taking the photos. 

He then had me zoom on in a little closer…

ISO 200
ISO 3200
Notice how the second photo is all dirty looking.  That’s the “noise” he kept talking about.  I might be getting it.

Summary:  Higher ISO = messy close up photo   Lower ISO = pretty and clean photo

What questions do you have about ISO?  We will answer those and the aperture questions this week-end.  Hopefully.  I’d also like to set up a Flickr group to force you all to practice now instead of putting it off.  Peer pressure!  I’ll keep you posted!