I S What???
Wed, Nov 12, 2008
Know ur stuff – ISO
In traditional (film) photography ISO (or ASA) was the indication of how sensitive a film was to light. It was measured in numbers (you’ve probably seen them on films – 100, 200, 400, 800 etc), on the boxes themselves. The lower the number the lower the sensitivity of the film and the finer the grain in the shots you’re taking.
In Digital Photography ISO measures the sensitivity of the image sensor. The same principles apply as in film photography – the lower the number the less sensitive your camera is to light and the finer the grain. Higher ISO settings are generally used in darker situations to get faster shutter speeds (for example an indoor sports event when you want to freeze the action in lower light) – however the cost is noisier shots. In the pic of st paul, grain can be identified, as its shot using iso 1000. Click on the pic for a full sized one.
When i say ‘noisier’ and ‘grainy’ it actually means how smooth the picture is, at low ISO, the picture is smoother and more fine and tends to get more harsh ‘grainier’ towards high ISO’s. Grain and noise are both the same term.
When choosing the ISO setting I generally ask myself the following four questions:
- Light – Is the subject well lit?
- Grain – Do I want a grainy shot or one without noise?
- Tripod – Am I using a tripod? a tripod eliminates the need to use a higher ISO value because its less prone to vibrations
- Moving Subject – Is my subject moving or stationary?
Situations where you might need to push ISO to higher settings include:
- Indoor Sports Events – where your subject is moving fast yet you may have limited light available.
- Concerts – also low in light and often ‘no-flash’ zones
- Art Galleries, Churches etc- many galleries have rules against using a flash and of course being indoors are not well lit.
- Birthday Parties – blowing out the candles in a dark room can give you a nice moody shot which would be ruined by a bright flash. Increasing the ISO can help capture the scene.
ISO is an important aspect of digital photography to have an understanding of if you want to gain more control of your digital camera. Experiment with different settings and how they impact your images.
Important: Compact digital cameras are usually set on default, so the ISO value is set auto, you may have to go to custom settings to change the ISO value, Enjoi.
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November 13th, 2008 at 2:49 AM
Nicely written and good examples.
you wrote “ISO is an important aspect of digital photography” and how about getting a high Megapixel DSLR camera? will it somehow help to solve this noise-grainy picture and ISO values dilemma?
-Azrin-
November 13th, 2008 at 2:51 PM
I never bothers about iso when i was using my nikon e5700. I just can’t do it. not even on iso200. it doesnt even give much effect on the shutter speed, but the noise is speechless. I can’t appreciate it until now. now I can!
November 13th, 2008 at 5:05 PM
Hello,
the higher the megapixel, the picture will tends to grain. Plus, the ISO performance is also depend on the sensor of the camera.
November 13th, 2008 at 7:18 PM
yup,
its true what brother fadhlullah said, it seems that for a normal DSLR not using full frame (another type of sensor which i will talk in detail later, the higher the MP ,the easier it is to become noisy with the increase of ISO. My advice would be to use a tripod, use a lens with a large aperture, f1.4-f1.8, or use your largest possible aperture. A lens with Vibration Reduction (VR) for nikon, or Image Stabilization (IS) for canon can also help.
Il post up ways to hand held a DSLR at night as used by professional photographer Joe McNally. So keep visiting for more updates. ; )
March 13th, 2009 at 11:11 PM
lately,i’ve realised by getting a fast lens (prime len) is really help a lot in taking night shot and low lit scene..it is true what ADMIN says..