Part.3 F-stops (How they work)

F-stops

F-stops control the diameter of your diaphragm (aperture). The f-stops are clearly marked on the lower ring of your lens. (Some new lenses designed for digital cameras will not have this ring.

For now on we will refer to the iris opening as the aperture. The f-stops control the aperture.




Opening up one full f-stop doubles the amount of light entering the camera. Closing down one full f-stop cuts the light in half.

f/2.8 lets in twice the amount of light as f/4, f/4 lets in twice the amount of light as f/5.6, f/5.6 lets in twice the amount of light as f/8, and so forth.

A typical f-stop sequence wil look like this:

f/1.4 - f/2.8 - f/4 - f/5.6 - f/8 - f/11 - f/16 - f/22

The full range of f-stop number :

f/1 - f/1.4 - f/2 - f/2.8 - f/4 - f/5.6 - f/8 - f11 - f/16 - f/22 - f/32 - f44 - f64

Becoming familiar with your f-stops is very important. Knowing the full sequence of f-stops will be a valuable tool in the future.

A helful tip is to remember that with minor varitations, each whole f-stop is twice the f-stop that is two stops back.

Take a look at the sequence above.

f/1 will let in the greatest amount of light while f/64 will let in the least light.

Knowing this we will now move on to lens speed. Lens speed simply refers to the greates amount of light your lens will let in.

A fast lens is a lens that allows in greater portions of light and a slow lens refers to lenses that let in small anounts of light.

A typical fast lens would be f/1.2 - f/1.4 - f/1.8

These apertures allow for much more light to enter the camera.

Slower lenses such as f/2 - f/2.8 - f/3.5, let in smaller portions of light.

When more light enters your camera the less time is needed to expose the film or activate your digital sensor to record an image. Slower lenses need more time to record the image.

A typical fast f/1.4 Fujinon lens.



I hope you can see why we call f/1.2 and f1.4 fast lenses.

Prt. 2 The Camera and Lens

Paris, 1839, Daguerre introduces the world to photography. America’s George Eastman brings photography to the masses in 1890. The Germans jump onboard and bring the highest quality of engineering and optical performance to mass-market production; by 1920 Leica and Rolleiflex are introduced and remain on the market for many years to come. The Japanese are not to be left out, by the1950’s using computer technology they design lenses and optics of very high quality. They then took micro circuitry concepts and computer chips to a new level developing the metering systems, automatic exposure systems, and auto focus systems that we take for granted today.

And now the digital age!

Photography has come along way.

What is a camera?

1. A camera is a lightproof box. That’s all there is to it. The body keeps unwanted light out.

2. A lens is glass that gathers light rays and focuses them to form an image on film or your digital sensor. Most lenses contain multiple lens elements. (More than one piece of optical glass.)



3. Film/Digital Sensor – film is a light sensitive material (silver halide) that records your images when treated with chemicals. A digital sensor reacts to the light and stores information onto your memory card.

4. Your viewfinder shows you the image that will be recorded. Some viewfinders are just little glass window (rangefinder cameras) while other viewfinders allow you to view directly through the lens, such as an SLR /DSLR camera.

5. The shutter is a mechanical or electronic device that controls the length of time that light is allowed to enter your camera.

6. The shutter release simply activates the shutter.

7. The diaphragm is the lens opening, which varies in size. The opening controls the amount of light that enters the camera at any given time. The “iris” (diaphragm) is a series of metal leafs that overlap leaving a circular opening in the center. This opening can be made large or small by rotating a ring on your lens. Some camera lenses are auto focus and will automatically change via a microchip.

8. Film advance is a lever on manual cameras used to advance film to the next frame. Auto focus cameras will advance automatically, digital cameras the same.


This is the basic camera design. Digital cameras of course have much more circuitry but the light tight box and amount of light let in to capture an image are of the same principal. This may seem old hat to many who read this, but to those who just picked up a camera this is information well worth reading.

Prt. 1 With Eye's Wide Open...

Photography is more than a passion, for me it’s a way of life and enables me to view the world from a different perspective.

I started taking simple snapshots as a young boy with an old Polaroid B&W instamatic camera. This takes me back to 1974 – 1975 or there about. I fell in love with photography after watching my first polaroid print develop before my eyes. From that very moment I knew photography would become part of my life in some way, shape, or form.

Moving into the new era of photography has been very exciting. There have been many discussions on film verse digital. I use both medias and I enjoy both medias. I feel photographers should use whatever media makes them happy and concentrate on the important aspects of making a good image. It’s not how we got there; it’s getting there that counts.

The eye of the photographer is the foundation on which all good images emerge. We need a theme and more importantly we need to focus attention on the theme. Keeping a photograph simple (eliminate everything that might distract) helps to meet these goals.

I completely understand that art is subjective; you cant please everyone with every image you take. Focusing on a theme and keeping your image simple will move you in the right direction.

Until next time…