3. Different Lenses

Almost all this information comes from lessons by Chris Parker & Chris Bray, including the images. Information on tilt/shift lenses and those photos come from the Creative Live channel on Youtube.

There are a few basic types of lenses: standard (prime), telephoto, wide angle, and others. It’s good to have one of each of these, although many of them are prohibitively expensive. Most lenses have a zoom feature. To zoom in or out, just twist the barrel of the lens. 

Lenses also have the ability to focus - you can twist the outer ring of the lens (the part farthest from you). Most lenses have an option for manual or auto focus - it's a button on the side. Don't turn the focus ring while it's in auto mode! In general it’s good to set your lens to autofocus and turn on the stabilizer - this limits blurring from your camera shaking (if you’re using a tripod, turn the stabilizer off, as the lack of real shake can cause the stabilizer to add blur)

All lenses have a set focal length, which is a measure of how the light is focused inside the lens, and this is what allows for wider or narrower fields of vision in the lens. The smaller the focal length, in millimeters, the wider the field of view:

The higher the focal length, the narrower the field of view:

When you zoom in or out, what you’re doing is changing the focal length of your lens.

Photographers will often talk about the “speed” of a lens. Lens speed refers to how big the aperture can be. The smallest possible F number (the largest opening) is the "speed" of that lens. It lets you know how quickly you can get lots of light through the lens.

All lens glass has special coatings that reduce light reflections and unwanted optical effects like moiré patterns (seen here in the door): 

Be sure not to scratch or mess with the glass! Use only appropriate lens cleaners to wipe your lenses.

Standard Lenses (50mm)

These mimic the way you see in real life – the focal length and aspect ratio are the same as your eyes. The one pictured above is also a prime lens (see below).

Wide Angle Lenses (anything less than 50mm)

These take a more panoramic view, fitting in more from right to left.

Wide angle lenses are popular for weddings and real estate photography:

When you get to extremely wide angle lenses, they are referred to as “fish-eye” lenses:

You can tell it's a fish-eye lens because the glass on the front is dome shaped, not flat, like other lenses. Fish-eye lenses distort the image to emphasize what's in front of you, and to de-emphasize what's in your peripheral vision.

Telephoto Lenses (anything above 50mm)

These have a narrower field of vision, but allow for you to zoom in to a great extent, like a telescope:

Telephoto lenses can be very expensive, but there is a cheaper option, to double the magnification, by adding a teleconverter, although this can potentially lower the quality of your image:

Macro Lens

These are for extreme close ups of things. With a macro lens you can get really close to an object - with a minimum focusing distance of 5-7 inches, and still get a great shot - compare to telephoto lenses that usually have a min focusing distance of 5-6 feet. Technically, every macro lens is a prime lens, with a focal length fixed at 60mm.

With a macro lens, you get to look at the world on a micro scale:

Macro lenses are also great for portraits, because they naturally use a very small F number for aperture (see lesson on aperture).

Prime Lenses

These are lenses with no zoom feature, and are typically cheaper than zoom lenses, although they can be extremely expensive (i.e. for a wider aperture range, or a high focal length - I saw a 300mm prime lens sell for $5,000). Why do people buy them? They are designed to do just one job, and do it perfectly. With a zoom lens, what you have is a trade-off––quality versus versatility. A zoom lens isn’t perfect because the glass of the lens isn’t crafted perfectly for one exact focal length – it’s meant to be merely adequate for a range of lengths. Additionally, as you zoom out, the telescoping introduces a bit of wobble, and it can sag down ever so slightly, so the optics might not line up perfectly. A prime lens avoids all this. So, in addition to sharper images, prime lenses also tend to have larger apertures, making them better in low-light situations, and for blurring out backgrounds. This is why some professional photographers claim that zoom lenses are for amateurs - but it's debatable. Many professionals prefer zoom lenses.

Tilt/Shift Lenses

These special lenses can change the perspective of your subject, without you having to move to another angle. The shift feature can change your view so that objects above you (trees or buildings) that would normally converge on a vanishing point, instead seem to go straight up and down. This makes them ideal lenses for architecture.

This comes in handy in nature as well, where perspective could make a tree appear to be falling backward. Use the shift feature of the lens to correct it:

Tilt/Shift lenses also take great panoramic shots – by shifting, you get photos that line up perfectly, much better than when you pan your camera and take a series of shots with a standard lens. Tilt/Shift lenses are also wide angle, which helps for getting big views. You can even buy a macro tilt/shift lens. Because of the complexity of these lenses, most, if not all, are manual focus. And, because they are so expensive, most photographers only rent them.

A Lens Baby

This is a brand of specialty lenses that create special effects. There are different kinds of Lensbabies. Most have no focus or aperture features. It's like a little accordion, you can grip the lens and point it in different ways for a variety of effects. Generally, what's in the middle should be in focus, within a circular frame. Everything outside that circular window will be blurry and distorted, like this:

photo by Elizabeth Wilson.