Digital film speed...

plays a mighty important role in achieving professional looking photographs. The wrong digital film speed can totally ruin an otherwise perfectly good shot.

There are three interdependent variables in digital photography.

Shutter Speed

Aperture

Film Speed

Throughout the pages of this site I talk about how these three interrelate. For now just remember each will affect the other two. When you understand and find the correct balance of your shutter speed, aperture and digital film speed, your snapshots will transform into photographs.

Most teachers of photography start by explaining shutter speed and aperture.

I choose not. I start with digital film speed.

In the olden days of the 20th century when everyone shot with film cameras, film speed made little difference. Once loaded into your camera it was no longer a variable to be considered.

When you load your camera with film of a given speed you are stuck with that speed until you either run out of film or waste the remainder and put in a new roll.

All you had to know about film speed is fast film equals fast subject, slow film equals slow subject. Except for artistic effect.

So, you load film according to what you intend to shoot. Then you shoot.

I love film photography. It is beautiful. It is art. It is very worthwhile. Yet I choose digital.

Digital film speed is to be considered with each and every picture you take. It can change with each shot.

When you are shooting with digital

film speed is a much more integral part of your basic camera settings. For example let’s say you’re sitting there minding your own business, shooting a pretty little flower.

Well, odds are you are using a wide open aperture and a film speed of 100 ISO for absolute clarity of a 16”X20” framed photograph. (Just for the record, that is a slow digital film speed)

Suddenly you look and see a Great Blue Heron. He is a little figedy and you just know he is about to take flight. Well 100 ISO film speed will never do!

You know full well that if you bother to shoot him at that film speed he’ll be all over the frame and just be one big blur. “Oh, My!” You exclaim. “What ever shall I do?”

Well, lucky for you, you are a regular reader of my site. So, you are very familiar with the quick change digital film speed built into your camera and in less than a second you are set to 600 ISO and pointing directly toward this majestic creature.

As he takes flight you click away at 5 frames per second. Because in that same split instant you knew enough to also set your camera to “Continuous” mode for both your shutter and your focus.

Lucky you, you end up with a whole series of Great Blue Heron flight shots from which to choose!

Now you happily go back to your flowers who have been ever so patiently awaiting your sweet return.

Digital film speed is important and…

it is pretty easy to remember. Fast film speed for fast moving subjects. Slow film speed for - - - well I think you get it.

One thing to keep in mind is that as you increase film speed the quality of your prints decreases. That's why you don't permanently leave your camera set on a high film speed.

You can change your digital film speed before each time you press the shutter release button. This means you can get a wide variety of types of photographs just by changing a setting or two. Isn’t digital great!?

Shutter speed is important because…

a fast shutter speed allows you to shoot a moving subject and get a crisp picture. Film speed, at crucial times, allows you to use a higher shutter speed.

I am starting with film speed because once I have my basic camera settings I find I change film speed more frequently than the other two. (Aperture & Shutter Speed)

Take a look at these two pictures.

I went to the extreme with these two pictures to make my point. Notice the first picture has bright color and nice tone quality. The second picture is very grainy and lacks bright colors and clarity.

The first picture was taken at a film speed of 100 ISO. For our purposes, ASA is the same thing as ISO. The second picture was taken at about 1600 ISO. Both pictures are drastically enlarged to show the difference.

The purpose of this demonstration is to say that if all your pictures are going to be printed at 4”X6” your film speed will make very little, if any, difference.

However, if you ever want to enlarge your shots or if you choose to crop a picture you will see a difference in the finish picture depending upon the film speed you use.

Film speed and shutter speed are proportional. As you decrease film speed your shutter speed decreases by necessity.

You will want to use the slowest film speed possible. But not so slow that the matching shutter speed causes the image to blur. That is why you switched from 100 ISO, while shooting the flowers, to 600 ISO for the Heron.

With practice and experience you will learn what works best for you.

The ISO number is film speed.

That is the speed at which a given film can capture a picture for you. All other variables being constant, a higher film speed allows you to capture a moving object that would otherwise blur.

The following information on digital film speed is applicable to pictures taken in natural lighting.

Not those taken with a flash unit. Flash is another subject all together, though some of the information overlaps.

Another way I use a higher film speed is as the sun is getting low in the sky, or any low light situation. I can continue shooting a moving subject in the lower light. And I can hand hold the camera later in the day with a faster film speed.

In other words it extends the daylight hours I can shoot. And it offers more times I can shoot without the need of a tripod. Though I lose quality, the loss will only show if I am enlarging the prints.

Film speed 640 ISO, Aperture setting 5.6 and shutter speed of 1/10th of a second. I shot this carousel on a rainy day, inside the protective enclosure.

I hand held the camera by perching myself against the railing. A higher film speed, but at this size and at least up to about 8"X10" the quality is great.

I don't like to use a tripod. They are too restrictive for me.

Here’s how I choose film speed.

If you have a subject that is completely still like landscape 100 ISO is normally a good choice. Many times one will want to crop and/or enlarge a landscape picture.

Shooting at a slow film speed the camera captures more of the details. (As in the gas can picture above) This allows you to crop and/or enlarge while retaining a crisp finish.

Shooting people, even if they are posing I start at 200 ISO. Invariably people move! In the brightest of lighting you can still shoot at 100 ISO should you so choose, but the difference in quality is negligible.

You can even use 400 ISO if you are posing children and want to ensure sharp pictures.

Moving on up to active children and pets, I start at 400 ISO and go up from there. In good lighting 400 does a good job. In shade or on a cloudy day, you may even want to go up to 800 ISO.

On the other hand if you are shooting a speedboat slamming past you down the river you will never get a crisp picture at 100 ISO. That is when you will want to use something closer to 1,000 ISO.

Now it’s time to enter another variable.

Sunlight. If the sun is high in the sky and shinning brightly you will use a lower ISO than if it is cloudy or the sun is near setting.

Early in the morning and as the sun sets you will increase your ISO setting.

There you have it; some guidelines…

for different types of photography and what film speeds work well. This will give you the highest quality prints in each type of shot.

As I always say, if you will be cropping or enlarging your pictures you will want to make sure you use the appropriate digital film speed for each type of shot. This will give you the best quality possible in each shot.

If your pictures will be used only for 4”X6” prints or on a digital screen you need not concern yourself about the noise caused by fast digital film speed.

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