LENS INFO

Lens Lingo

One of the things new photographers grapple with is lens lingo.
What do all those numbers and abbreviations mean?
We’ll start with the kind of lens, or lenses, that likely came with your dSLR.
Note: Each camera maker has their own lens mount design. Nikon lenses (F-mount) cannot be directly mounted on Pentax cameras (K- mount). However, someone may make an adapter that allows such a mash up.

Two Lens Types

There are 2 lens types:

Digital SLR Camera Settings

More people than ever before are using digital SLR cameras.

When film was the primary medium people used to make photos, you didn't get to see your photos until they were printed. If you didn't do your own darkroom processing, you relied on the photo lab to develop the negatives and make the prints for you.

Now, dSLR photographers can see a small version of their photo right on the camera, but if they want those photos to display nicely on a computer monitor, somewhere online, on some other digital device or have it printed, there are choices about camera settings that need to be made. Those choices can have a big impact on how sweet your photos look and how much editing you can do to them and still have them look nice.

Each camera has many settings, and most are covered in each camera's users manual, but 2 of the more important, somewhat esoteric settings, are worth taking a closer look at.

Recommended Reading - Technical

The technical aspects of photography seem daunting to a lot of new photographers. From a technical viewpoint the basics are really rather simple and can be conveyed without much muss or fuss.

One of the best at doing that is Bryan Peterson. Bryan is a successful professional photographer that also has a gift for explaining technical aspects of photography in easy to understand ways. I recommend three of Bryan's inexpensive, yet information packed books:

Recommended Reading - Composition

I have a couple of book shelves filled with various books I have read on the many different aspects of photography.

A lot of new photographers aren't aware of many of those books so I decided it would be helpful to let people know about them.

My book collection covers several different aspects of photography:

The In-Camera Light Meter

Since we rely so heavily on the in-camera light meter it's very helpful to have a good understanding of how it works and how you can configure it so it provides you the most reliable information.

Reflected Light and Algorithms, oh my!

Your in-camera meter measures how much light is reflecting off the scene it is metering. If everything reflected the same amount of light we would be home free. Obviously, a nice polished piece of chrome on a motorcycle will reflect more light than the skin of a pretty girl sitting on the bike.

Since the amount of light being reflected from different parts of the scene varies, in-camera meters measure the light intensity in different parts of image and uses an algorithm to determine the most suitable exposure for the final picture. We get to tell the meter which algorithm to use. Well, the camera manufacturer gives us the chance to select from several metering modes that each represent a different algorithm.

Using The Exposure Adjustment Triad

Exposure is the total amount of light allowed to reach the image sensor during the process of taking a photograph. We've seen there are 3 things that we can adjusted to control that exposure: the lens aperture, the shutter speed and the ISO sensitivity.

The DSLR Reflective Light Meter

Your DSLR has a built-in reflective light meter. It tells you if your current settings will make a good exposure or an over/under exposure.

Exposure...Part 3 - ISO

ISO - Sensor Sensitivity to Light ISO stands for the "International Organisation for Standardization". The ISO was founded in early 1947 and is headquartered in Geneva, Switzerland and is composed of representatives from various of it's 158 members national standards organisations.

One of the standards defined by this organization is photographic film's sensitivity to light. An image sensors 'film speed', is often referred to as its "ISO number."

ISO - and Stops of Exposure

Just like aperture and shutter speed ISO is set up as multiples of 2. ISO 100 allows twice as much light as

Exposure.....Part 2 - Shutter Speed

Today's DSLR cameras use a two curtain focal plane shutter.

At left is an image of a two curtain focal plane shutter part way through the sequence of making an exposure. The image sensor is immediately behind the curtains.
This shutter was set to 1/500th of a second. Both curtains move from the top to the bottom. The front curtain is released first and in this image is near the bottom of it's range of travel below the black horizontal gap low in the image. The rear curtain follows close behind due to the the 1/500th of a second shutter speed.
The gap between the two curtains travels down and is spaced to expose each part of the image sensor for the required 1/500th of a second.
Once the exposure has been made both curtains get reset to the top of the frame so they are ready for the next exposure.
If the shutter had been set to 1/60th of a second the front curtain would travel all the way down before the