Photography Tips: What Does the ISO Do For You?

Kissing, Image shot at ISO 1600.

To really understand what ISO is and what it does, and to really get it you need to know first what it was before digital cameras. After that I'll try to get down to what it is and why it is important. This is a more technical photo post, I hope you follow. Please let me know if something I say is unclear, because I am sure someone else will have the same question.

What the ISO was: It was, in the era of non-digital cameras a number that was written on the individual film rolls that you purchased for your camera. When I was in photography class, we used ISO 400 to allow for more light and quicker shots, such as sporting events or low light situations, and ISO 200 for regular headshots or point and shoot people events. So the higher the ISO the film had, the more light it allowed in. In the past (when using film) you were stuck with one ISO setting for that entire roll, no adjustments.

What the ISO is now: Now that the world has skip, hopped and jumped forward to digital cameras the ISO means something similar, but without using film. It is another adjustment you can make when taking pictures and want to allow for more exposure (let in more light, make your shot brighter). You can fidget with the light meter, the shutter speed, and on a digital camera you can mess with the ISO as well. The higher the ISO, the more light that will be allowed in, the more light sensitive that that shot will be.

According to Ben Long in The Cannon EOS Digital Rebel XSi/440D Companion, "ISO  is a standard for measuring the sensitivity of film. Digital vendors have adopted the standard for specifying the sensitivity of a digital image sensor. When you increase the ISO setting on the Rebel XSi, you're essentially making the sensor more light sensitive. As the sensor becomes more sensitive, it will require shorter exposures to be able to "see" a scene"  (p. 93)

The way digital cameras are set up now you can shoot at an ISO of 1600 which enables you to shoot with the image sensor, so sensitive that it allows you to take photos in a much lower light than was ever possible with film.

The benefits to a higher ISO are:

• Ability to shoot in a setting with much lower light and still capture a great shot.
• Enables you to take pictures of sporting events, stopping the action in time.
• Gives a shot a much greater depth of field.

Drawback to shooting with higher ISO: So why not always shoot allowing for the most light to enter the shot with the highest ISO possible? Well, there is a setback, that I didn't really know about until doing my homework for this little photo post. Since I hate my flash, I have just been increasing the ISO all the way up to the max (on my camera it is 1600) which does make the sensor really sensitive, however, I have been noticing (lately) a little of what is known as "noise" by the pros. Noise is what happens when you increase and amplify any type of electrical signal, which is what you are doing when you increase the ISO. Along with the signal of data you want, you will increase the static or noise. Think old-school radio and then you'll get it.

Noise is photo static, it looks grainy, not sharp, even sometimes can look blurry or distorted (in extreme cases of course). Most of the time you won't even see it until you enlarge your pictures, then in the shadowy areas especially it is bumpy and grainy. That is noise.

My conclusion after doing my homework on the ISO ins and outs:

If you are interested in the best image quality and sharpness, here is the rule I'll give you: Shoot at the lowest ISO possible to make the shot. To do this you can mess around with the light meter and shutter speed and try to get the ISO down. However, If it isn't possible, than of course a photo with noise is better than no image at all, so just shoot away. Don't stress it!

When using the camera that I have, the Cannon EOS XSi/450D My noise complaints are extremely low, even when shooting at an ISO 1600.  I would rather increase the noise on my shot, which doesn't really bother me a ton and get the shot without using the flash than turn the flash on.

Photo Examples of shooting at high ISO:

Bread Image shot at ISO 1600 If you click on it and you'll see some noise. For me that adds to the effect of the depth of field, so it doesn't bother me.

Boys, Image shot at ISO 1600, now that I look at this one there was no reason for it to be shot with an ISO that high since it was outside, and I do see the noise and don't like how it fights with the sharpness in this shot. I am learning.

Converse, Image shot at ISO 1600 this shot too, it is just fine the way it is. I guess I'll never know what it could have been, but really now, does that matter? ;)

I always love answering questions for readers. I’d love ideas on future Dreadlock Girl Photography Tips sessions if you have them. Leave me a comment, I love hearing from you!

Previous Dreadlock Girl Photography Tips:

The Basics
Capture Real People, In Real Life Shots
Work That Thing! How to Get the Best Shots
Tips for Group Shots: How to Shoot a Group Session Like You Know What You’re Doing!
Photo Editing, Fixin’ Your Images
Taking the Best Black and White Photos: What to Look For
What does the ISO Do For You?: Learning more about the ISO

Dreadlock Girl Photography Tips: I am going to do several of these posts, I am not a professional photographer by a long shot, but I love taking pictures and seeing beautiful pictures so I want to share what I have learned with you.

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