ISO Settings

What are they and why would I change them?

Digital SLR Photography Tips - The ISO Settings

​What are ISO camera settings and what does ISO mean? Well, ISO ​is the company name for ​the International Organization for Standardization. The name comes from the Greek word "ISOS" meaning equal. ​They set the ISO numbers for sensitivity of emulsion based film and digital sensors in photography as well as numbers for many other things.

ISO numbers in photography include:

  • 100 ISO being not so sensitive (and the standard ISO used by most people) to:
  • ​6​400 ISO which is extremely sensitive to light

In the beginning, for me anyway, I tended to use just 100 or 400 ISO film (or ASA as it was then). I didn’t really know any better. I used 100 ISO for normal, everyday use. Keeping the 400 for either indoors, black and white or colour "grainy" shots. 400 ISO was useful for indoor shots where flash couldn’t be used. Environments such as because with the extra sensitivity, I could still get decent shots.

ISO and film problems

The major headache with film photography was that if you wanted to change the ISO settings, you had to change the film itself! Not good if you were in a hurry. There was a way to "push" the film by underexposing it to get faster shutter speeds, and sorting out the mess in the darkroom later. However, you still had to "push" the entire film and not just individual frames.

ISO Settings

The beauty of digital is that you can alter the ISO for each individual shot. I have found myself changing ISO settings so much more often.

This means, should you come across a situation where you are in low light and cannot use flash, you can just up the ISO settings. Increase them to 800, 1600 or even 3200 making the sensor a lot more sensitive to light. Then simply fire away knowing the images will come out OK.

For example, we once took my son to the Zoo in Spain for the first time. All the shots taken outside were at ISO 100 as the midday sun in Spain is very bright.

Then we entered the reptile house and the light died . The only illumination was coming from the reptile's enclosure, and I had no flash unit.

No problem, I just whacked the ISO to 1600 on the EOS 20D and fired away. This shot below was taken hand-held at 30th of a second. I used a heavy 70-200mm lens at F3.5 (although it has IS or "image stabilisation").

Neat Image

I cleaned it up a little using Neat Image, but not much was needed. Once we were outside again, back to 100 ISO. It has "revolutionised" the way I take photographs now. Click image above for larger version​.

If you get in a situation where you have the aperture fully open and the shutter speed selected is too slow to hand hold. Settings such as 30th or 15th/sec. Use the higher ISO settings. They are like a Godsend in digital photography, especially if you don't carry a flashgun.

The opposite is true here as well. Where high ISO's give grainier, lesser quality images, a low ISO such as 100 or 50 will produce the finest quality, grain free images that your camera is capable of. This is worth remembering if you are doing important work with your digital SLR. The Kodak Pro series of digital cameras went as low as ISO 6!!! Imagine the quality there!

With film, anything above ISO 400 would produce grainy and textured images. The techniques in the 80's and 90's for reducing grain were few and far between. However, a new breed of digital cameras came along in the "noughties! Cameras such as the older, almost "grain free" Canon EOS 20D, 30D, 40D and later Canon EOS 5D Mark IV. The "noise" as it is also known, in some of these camera's images are barely noticeable.

Even if a bit of grain or noise does appear, there are programs such as Neat Image available. This cool bit of software will all but remove any signs of grain. Amazing!

Try this

If you own a digital SLR, play with these ISO settings to see how it can improve your photography. Purposely leave your flash at home and turn the ISO settings right up to see how it functions. Heavy grain in some images such as buildings or landscapes can really add great, moody effects to your shots.