Photography lesson: Why is it so noisy in here!?

It's been simply ages since I posted a photography lesson (Since I was 26 weeks pregnant with MckMuffin to be exact...and today is my due date, meaning I'd be 40 weeks today! You know, if he hadn't already been born three weeks ago.). If you would like to read my other photography posts, you can click on the thus-named label in my left sidebar. I figured tonight was as good a night as any to offer up some more tips finally. I know, I know. You're welcome. I'd let you thank me in the form of apple crisp, but now that I'm no longer pregnant, I can't stand the stuff.

Ahem. Anyway, we forge ahead.

With the hope that this encourages you, please know that I am most largely a self-taught photographer. I did major in Studio Art in college (I triple majored, actually, along with Bible and Education.) and attended my share of photography classes. But nearly all of what I know about digital photography, I learned on my own, starting after Big Mac was born.

If I can do it, so can you!

Regardless of where you are at along the road with your own photography, and regardless of what kind of a camera you shoot with, there is always something to learn and something to be inspired by. I know that's true for me.

So, if you'd like to take better photographs, buckle up and hold on tight because here we go again!

Today, we will delve a little into ISO (which is sometimes also known as ASA) and the issue of noise in photographs. I hope you enjoy this lesson!

I shoot with a Canon 40D, with a Canon Rebel xTi as my backup camera (I am a professional photographer and I do this for a living, so I figured I was justified in having two cameras even though I am not normally prone to excess!). It goes without saying that digital cameras are certainly par for the course nowadays. The cameras I shoot with are not point and shoots, like many of you perhaps use. Mine are called SLR's they are the kind of cameras with big lenses on the front of them. With the price of digital SLR's plummeting, they have become affordable for more and more people and I highly recommend one if you are interested in photography. But know this, an expensive (or even semi-expensive) camera is not a prerequisite for taking great photographs; besides, even upscale cameras can take bad pictures! Learning a few basic photography tricks, and getting to know the camera you do have, even if it is a point and shoot, can often take you further than just purchasing a fancy new camera could!

No matter what kind of a camera you have, you should be able to control the ISO on it.

"Hold it right there, MckMama," you're thinking. "What the heck is ISO!?" Why, I'm so very glad you asked.

ISO is the number indicating a digital camera sensor's sensitivity to light. The higher the sensitivity, the less light is needed to make an exposure. Unfortunately, the higher the number, the more noise. (We'll get to that in a minute.)

As you may or may not recall from the days of film cameras, film comes in a variety of speeds. Film speed is measured using a numbering system called ISO. Lower ISO numbers are indicative of slow films, which are less sensitive to light, while higher ISO numbers are more sensitive to light. It’s pretty typical to shoot with ISO 100 or 200 in normal daylight, and use 400 film for lower light photography. Super-fast films like ISO 800 and even ISO 1600 are available for photography in near darkness.

"And why on earth should I care about all this!?" Well, correctly using and understanding ISO will mean the difference between getting a blurry mess and a sharp photo.

To explain that to you, let me tell you what ISO means in the world of digital photography.

Lucky for you (And me!) you can control the sensitivity of your camera’s light sensor by changing the camera’s ISO setting. By default, most digital cameras have an ISO somewhere around 100. If you need more film speed for low light conditions, getting more sensitivity out of your camera is as simple as selecting a higher ISO from the camera’s menu. Most digital cameras offer a range of ISO values, such as 100, 200, and 400. Just dial in the ISO you need. By increasing the ISO, you will be able--even without using a flash--to capture crisp photos in low light that, at the default ISO, would have just been a blurry, slow-shutter mess.

That sounds great, right? And I know what you’re thinking: "MckMama, if higher ISO film is more light sensitive, why not always use a high ISO number?"

I'll tell you why not.

You see, dear friends, light sensitivity brings its own baggage. High speed film was notoriously grainy. As you increased film’s sensitivity to light, the light-sensitive grains of silver in the film emulsion got bigger and more noticeable. In the final print, that manifested itself as grainy, pixely (Is pixely a word!?) elements in the photo that took away the photo’s smooth, high-resolution look. Ironically, in the world of digital, almost exactly the same effect is present. Increasing the sensitivity of the camera’s light sensor introduces digital noise into the picture. Similar to film grain, noise is random pixels of color scattered on your photograph.

To illustrate this, let me show you that may not notice noise from a distance. See this photograph of biggest brother holding smallest brother? I took it the other night, without using a flash, in our darkened bedroom.



Looks okay, but if you click on the photo to see it larger, or if you take a gander at this zoomed in portion of the photo of Big Mac's face...



...you can actually see the noise. It’s hard to miss the grainy look of this photo, complete with zillions of specks of color. All digital images have some amount of noise; there is simply no getting away from it. But it gets worse as the ISO goes up. And I had to use a high ISO to take this photo in such low light.

You'll simply have to decide if the payoff is worth if for you: A higher ISO will mean you can take clearer photos in lower light without a flash (Straight flashes from your camera can be downright evil and I highly recommend steering clear of using your camera's flash if you can get away with it.) but it will also mean your photos will have more noise.

Play around with it and see where your happy medium is!

If, say, you're able to get enough natural light on your subject, then you'll be able to still get away with using no flash, but will also be able to use a lower ISO. A lower ISO means less noise. Look how much clearer this photo of Small Fry from the other day is:



I shot it with more available natural light (She was facing a window.) and was able to use a low ISO and got less noise. Click on the photo. You'll see some noise, but overall there is less than in the one of Big Mac above.

"So what should I do about ISO?" Great question, again! I suggest shooting at the lowest possible ISO all the time. In ordinary shooting conditions, stick with the camera’s lowest ISO level, since that’ll give you the least digital noise. But when you notice that your camera is recommending a really slow shutter speed, or your photos are starting to look blurry and hazy when you don't use a flash, then just crank up the ISO. But don't forget to drop it back down to the lower value when you’re done, so you don’t accidentally capture a month’s worth of pictures at ISO 800.

Another thing to keep in mind is that your digital cameras is not likely to allow you to adjust the ISO when you’re in the camera's automatic mode (Which is quite possibly the mode you are used to shooting in.). To tweak the ISO, you’ll need to be in program, shutter priority, aperture priority, or a scene mode.

Good luck! Let me know what you thought of this post, try out the techniques, keep practicing and check out my other photography lesson posts here and here if you're interested in learning more.