Choosing Camera Lenses

Choosing camera lenses demands both knowledge of and experience with different types of camera lenses. Although knowing which lenses work best in given conditions is important, a photographer also chooses a particular lens to produce a specific photographic effect. Light, composition and subject matter of a scene all influence photographers’ choices of lenses.
Wide-Angle LensAlthough some will take landscape shots with telephoto lenses, most photographers opt for the wide-angle lens. Because a wide-angle lens has a wider field of vision than the human eye, it can take in more of a topographical expanse. Consequently, the wide-angle lens is one of the preferred landscape camera lenses.
A wide-angle lens can focus on the foreground and background simultaneously, another ability that the human eye lacks. Wide-angle camera lenses are best for large, dynamic landscapes where background and foreground both catch the eye’s attention. However, a photographer should refrain from using a wide-angle lens if he wants to focus in on the details of a single, distinct subject.
Zoom LensA zoom lens allows the photographer to widen or shorten the lens’ focal length to increase or decrease the magnification of the subject. This feature makes the zoom lens a popular camera accessory in many types of photography, ranging from landscape to portrait photography. However, because zoom lenses have small apertures (or lens openings), they are not well suited to taking pictures in low-light conditions.
Zoom lenses have replaced the fixed focal length camera lens in most camera models, especially with the advent of digital cameras. When choosing camera lenses, bear in mind that an optical zoom lens and a digital zoom lens are different.
While an optical zoom lens magnifies the image, a digital zoom lens crops the image after the maximum zoom is reached. Essentially a digital zoom enlarges and crops the image seen in the viewfinder instead of magnifying the subject. This digital enlargement results in lower resolution and, therefore, a poorer quality image.
When choosing camera lenses with zoom capabilities, photographers should look for high optical zoom capabilities rather than being deceived by claims about digital zoom capability. Pictures are of much better quality with an optical zoom lens.
Telephoto LensThe difference between a zoom lens and a telephoto lens is subtle. A zoom lens enlarges and magnifies the image. In contrast, a telephoto lens brings the subject “closer” to the photographer, reducing the distance between objects in the photograph and the camera’s lens. This allows a telephoto lens to show greater detail than the human eye could see at the same distance.
Fixed-Focal Length Camera LensA fixed-focal length camera lens is a permanent, non-adjustable lens found on some low to mid-range quality cameras. Often (but not always) doubling as a wide-angle lens, fixed-focal lenses tend to work well for low-light photos.
A fixed-focal length lens can do wonders for beginning photographers by helping them learn the art of photography. Without zoom capabilities, the photographer must give more thought to basic photography composition to produce good quality shots. Consequently, a budding photographer may learn the basics of good photography faster if by choosing a fixed-focal length lens.
Fixed-focal length camera lenses are less common than they once were, in part because most mid-range digital cameras now have built-in zoom lenses.
The Macro LensA macro lens is used to take extreme close ups of objects. Its short focal length allows the photographer to take pictures at close distances without distortions. The resulting image is as large as, or larger, than the original subject.
Choosing a macro lens has been complicated by digital camera settings. Originally, a macro lens was an extension tube for the camera lens. However, today’s digital cameras often have a macro setting. Although the setting replaces the traditional lens, it stillproduces the same effect as the previous macro lenses.
Macro lenses or macro settings are best used for magnifying the details of already smallobjects. For example, a photographer can use his macro setting to photograph ripples in water, the dew on a flower petal or the crevices of a rock.
Fisheye LensFisheye camera lenses distort the subject image, producing photos with curved and convex appearances. The fisheye lens was first developed for astronomy photography that seeks to capture as wide a range of sky as possible.
Today, the fisheye lens has become popular with landscape photographers, as the lens distortion curves horizons and hints at the earth’s curve. A portrait of a person taken with a fisheye lens has the distortion similar to what’s seen when looking through a door’speephole.
Front of Lens AccessoriesChoosing among different camera lenses isn’t an issue for most mid-range cameras because they already have built-in lenses that cannot be changed. While single lens reflex (SLR) cameras have interchangeable lenses, their steeper prices tend to make them a tool for professionals or serious amateur photographers.
For the hobbyist who doesn’t have an SLR camera, front of lens accessories that mimic the effects of certain lenses are available. A front of lens accessory is a disc that clips onto the front of a camera lens to provide specific effects. While some front of lens accessories filter out light, others mimic the effect of a wide-angle or fisheye lens.
Photos taken with a lens clip on accessory lack the quality of those taken with camera lenses designed for the same effect. As choosing a lens is not possible with many cameras, front of lens accessories increase the average photographer’s options.

Infrared Characteristics

Infrared radiation has a longer wavelength (lower frequency) and lower energy than light from the visual spectrum. The spectral range from 700 to 1350 nanometers can be photographed but conventional cameras are limited to the range of approximately 700 to 925 nanometers. Infrared beyond the 1350 nanometer range can be imaged but only with special non-photographic equipment. Georg Dittie's Thermal Infrared & Thermography web page is a useful introduction to imaging in the infrared region beyond the grasp of conventional photography. The infrared region between 1000 to 1350 nanometers requires special photographic equipment and special order film. Infrared spectrum in the range from 700 to 925 is the region that is most accessible to conventional photography.
Most 35mm, 120 (6cm)and sheet film cameras can be used for infrared photography in the range of spectrum from 700 to 925 nanometers. A few of the newer plastic body cameras may not be completely opaque to infrared.
You can easily test your equipment to see if it is completely suitable for infrared photography. Load a roll of infrared film into the camera and fire off several exposures at high shutter speed and small f-stop, with lens cap in place and indoors. If you open the fresh film container and load the film into the camera in total darkness you will have a completely unfogged roll making the test results easier to interpret. This will leave blank, unfogged film in the exposure chamber of the camera. Now place the camera in full 10 am to 2 pm April to September sunlight in several orientations for about 20 minutes in each (lens cap on if it is a rangefinder!). Process the film to normal or slightly greater than normal gamma. If the film is fogged, the equipment is leaking infrared radiation. Inexpensive, older model 35mm cameras usually make good infrared cameras if your plastic camera body leaks infrared.
The same test works for sheet film cameras and film holders. Sheet film holders are particularly troublesome with infrared photography and should be kept in the dark as much as possible. Some film holder bodies and dark slides may not be opaque to infrared. The dark slide, light trap may also leak infrared. Some view camera bellows may leak infrared. The safest solution is to keep direct sun off of the camera and film holders.
Since the range of infrared spectrum beyond 1350 nanometers is thermal radiation and imaging here involves recording heat patterns, infrared film tends to be especially sensitive to heat and age fogging. The further the film's sensitivity extends into the infrared region, the more apt it is to fog easily. Store infrared film in a cool place and shoot fresh film whenever possible. Process infrared film as soon after it is exposed as possible to minimize subsequent fogging.
Most photographic lenses are designed so that they have the same focal length for all colors of the visual spectrum. They are not usually designed to correct focus for infrared light. On many lenses there will be a red line or dot near the focus index. This is the correction factor for infrared. You focus visually, then move whatever is opposite the focus index to the infrared mark. This adjusts the lens away from the film by about 1/400th of the focal length (1/4 percent) and brings the infrared image into sharp focus at the film plane.
Most infrared films are sensitive to light from the visual spectrum in addition to infrared radiation. Various sharp cutting color filters can be used to limit imaging radiation to the infrared region. The following table gives mid and maximum usefully recordable wavelengths for several commonly available infrared films.

Sports Photography

We have all at one time or another been captivated by sports images. It may be Kirk Gibson's World Series Homerun, and the image of him running the bases, overcoming the pain he was in or an image of high flying Michael Jordan slam dunking a basketball with his tongue out. We have all been captured in the moment of human drama. We all like a good action photo and, in particular, if your kids play sports, you want to remember them in their toils.
Quality sports shots are somewhat difficult to come by. Most people have limited access to events to photograph them. The further away you are from the event, the harder it becomes to capture the event in a pleasing manner. Sports are an event where crowd control is important, not only for the crowd's safety, but for the players also. There is nothing more frightening than to be on the sidelines of a football game, focused on a play in the field, when out of the blue a 250 pound line backer drives a player into your legs or a foul ball comes crashing at your $8,000 lens!
Location, Location, Location!
You can only photograph things you can see. The closer you are to someone, the better you can see them. Sports are no different. You have to get as close to what you are shooting as you can. Typically, for a photographer with a press pass, you can get to the sidelines or other similar locations. You generally will not be permitted on the playing field. Depending on the sport, you most likely will be limited to designated locations. For instance, at most Division I football games, the media cannot shoot between the two 35 yard markers. For most people, the situation is even worse. You probably don't have press access and are stuck in the stands for your shots. Get as close a possible. Even if you make it to the sidelines, you will be jostling for space with many other photographers, both still and video who have worked hard to get there and have the same job to do that you have.
You also have to be familiar with the sport to be able to capture the moment. This means knowing where to position yourself for the best action. This is critical because of angular momentum that will be discussed in the section on freezing action. Not only does it matter with the subject, but the background. Look at what is going to be behind your subject. While we will try to minimize the impact that a background has, it will still be unavoidable. So you need to position your self where the background is the most pleasing.
The Decisive Moment
Sports and Action photography is all about timing. Its about reacting. Its about being in the right place at the right time and its about execute. These are all qualities of the athlete and those of the photographer as well. Each sport has predictable and unpredictable moments. Under "Knowing your Sport", you will learn about these moments for individual sports. For instance, in basketball, you will have opportunities to photograph layups, jump shots, free throws, etc. Understanding the timing of these predictable actions allows you to capture the peak moment, when the action is most dramatic.
By knowing these moments you can anticipate the action. This helps in two ways, one it helps you with focus which will be discussed in a later segment, and secondly it helps you snap the shutter at the right time. The saying goes "If you see the action you missed it." This basically means if you wait for the soccer player to head the ball then press the shutter release, the ball most likely will be sailing out of the frame. You have to push the button before the action so that the mirror has time to flip out of the way and the shutter open and close. There is a delay between the image hitting your optical nerve and the shutter closing. You have to, through experience, learn what that time is and adjust for it.
Required Equipment
Most sports are shot on 35mm cameras because of their portability. While some photographers have captured great sports moments with other format cameras, we will concentrate our efforts on the 35mm arena which is the most commonly used gear.
"Its not the equipment but the photographer who makes the picture" is generally a true statement. However with sports and action photography, having the wrong equipment means not getting the shots you want or need. This relates back to the section on location. The further away, the longer the lens is needed to capture the same image in the frame. Different sports require different lens lengths. For instance, basketball is generally shot from the baseline or sideline near the baseline. You generally can get good results with an 85mm lens in this situation. However, by the time the players are at mid court, you need a 135mm to capture them. If they are playing under the far goal, a 200-300mm lens is needed to fill the frame well, yet for shooting a soccer game, a 300-400mm lens is needed for just about anything useful.
Generally, for a 35mm camera, each 100mm in lens focal length gets you about 10 yards (9 meters) in coverage. This coverage means that on a vertical format photo, a normal human will fill the frame fairly well. Thus, if you are shooting American Football from the 30 yard line with a 300mm lens, you will be able to get tight shots in an arc from the goal line to mid-field to the other 40 yard marker. As players get closer, your lens may be too long. Many photographers will carry two bodies with two different length lenses for this reason.
Lens speed is also a critical factor. The faster the lens, the faster the shutter speed you can use, which as the lens grows longer, this becomes even more important. This will be covered in the freezing action section in more depth. If you look at the sidelines of any Division 1 college football game or an NFL football game, you will see people with really big lenses. These range from 300mm to 600mm or longer and even then, they may have a 1.4X converter or 2X converter on. You need fast shutter speeds to freeze action with long lenses. Every F Stop you give up requires a faster film or less freezing potential.
Most consumer grade long lenses and zooms have variable apertures, but most are F5.6 at the long end of the lens. F5.6 is good for outdoor day time shots, but becomes very inhibiting for night games and indoor action. Most people use lenses that are F2.8 or faster. These lenses are very expensive. A 400mm F2.8 sells for over $8000 US. They are also very heavy and bulky. Using a monopod is a life saver with these big lenses.

Underwater Photography Primer

Underwater photography combines the challenges of (1) trying to make an aesthetic statement that hasn't been made by thousands of photographers who've dedicated decades of their life to the craft, with (2) trying to stay alive.
The easiest way
Get into submarine. Get out camera. Point. Shoot. Here are some examples from a 800' dive in the Cayman Islands.

The second easiest way
Snorkeling is much simpler than SCUBA diving. The key to snorkeling is to remember that the human body will always float. It just doesn't float high enough that you can breathe easily. However, if you add a few inches of extension to your mouth, your natural floating position will be more than sufficient for breathing. You can thus stay in the water for 8 hours without exerting any energy and wait for interesting subjects to drift or swim underneath.
If you're staying near the surface, you don't need a camera that can handle the pressure of deep water. A compact digital camera that has been augmented for snorkeling will work fine. Typically these cameras are specified waterproof to 10' but will work a little deeper as well. A good example is the Olympus Stylus 720SW, $320.
How did it work in the old film days? If you can find a Nikon Action Touch, you might be surprised at how good it was. This camera has a very high quality 35/2.8 lens and autofocus above water. Underwater, you set the subject distance with a convenient dial. There is a nice big switch that turns the built-in flash on or off.
The Action Touch sold for about $150 in the late 1980s, after which Nikon took it off the market and no company ever made a similar camera. The Japanese concluded that nobody is intelligent enough to focus a camera manually. All the cheap underwater cameras introduced after the Action Touch were fixed focus underwater and came with lower quality lenses.
Most film photographers would use slide film despite its attendant narrow exposure tolerance. This may have been because prints can never convey the drama and brilliant colors of the underwater world.
Here are some snapshots from an old Nikon Action Touch:

Note that an "underwater-lite" camera ends up being a great camera for rafting, kayaking, heavy rain, or any other time when you need a high quality waterproof camera but don't need high pressure resistance.
The bad thing about snorkeling is that nearly all of your photos will end up having a "looking down" perspective. Here are a couple from Hawaii (taken with the Nikonos V, described below):
The hard (case) way
Strap some tanks, ideally filled with Nitrox, on your back and dive. Many compact digital cameras, notably the popular Canon line, are marketed with accessory underwater housings. These rigid plastic cases typically cost around $160 and are designed for use at all recreational SCUBA depths, i.e., down to 130' underwater. A housed camera is never as easy to use as a camera designed specifically for use underwater, so if you are mostly going to be using a camera at snorkel depths, you are better off with a camera from the preceding section.
The hard way
What if a compact digital camera is not an adequate tool for the job? You can put any standard camera into a plastic bag. A plastic bag?!? Not just any plastic bag. A thick German plastic bag made by ewa-marine with a metal screw-down zip-loc top. These ewa guys make plastic bags for cameras of all sizes with various combinations of lenses and flashes.
We have tested some ewa-marine bags here at photo.net. To our amazement, they did not leak. However, we were never been able to use them successfully. The last time we tried the ewa bag was on a liveaboard trip to the Great Barrier Reef. The bag was stuffed with a Nikon 8008, SB-24 flash, and 60mm macro lens. As soon as I got to about 30 feet underwater, the bag was pressing up against the camera to the point that the controls were inoperable. The AF drive wasn't strong enough to rack the lens out against the pressure of the bag. The few snapshots produced in this matter were of substandard quality and, with a 20mm lens, there was pronounced vignetting from the housing (example at right).
Why Wide-angle Lenses Are Important
Now that we're deep underwater, let's talk about fundamentals rather than gear for a moment. One fundamental fact is that water magnifies. Thus you end up needing a wider angle lens than you thought. A 20mm lens on a full-frame digital SLR or 35mm film camera is not especially wide for underwater use.
If you have a longer lens, why not just back up? The problem with backing up underwater is that water tends to absorb red and yellow light. The more water between your subject and your lens, the bluer your subject will be. If your light source is on-camera (i.e., if you are using a flash), every extra foot of water between you and the subject addings two feet worth of bluing (one as the light goes from the flash to the subject and one on the way back to the lens).
Underwater photographers are thus very fond of very wide lenses and very powerful flashes.
Back to the Gear: the Rigid Housing System
If we don't like the plastic bag idea, what about going back to the rigid plastic housing idea that works so well for digital point and shoot cameras? We would need a housing custom-designed to enclose a digital SLR body. Then we would need some kind of extension matched to any particular lens that we might mount to that body. Then we would need some way of extending the enclosure to surround an attached electronic flash. Maybe we would want to have an off-camera flash connected via an underwater cord. Sound complex? It is, but it works and is the kind of system that most professional underwater photographers use. The oldest and most popular brand of underwater housing is Ikelite.
The Classic Nikonos System
For several decades, Nikon produced a line of flexible cameras that were inherently waterproof and pressure resistant. The most popular model was the Nikonos V. This was a rugged little rubber-coated body that took interchangeable lenses in 15, 20, 28, 35 (standard lens; works above water too), and 80mm lengths. The camera gave you aperture-priority or manual exposure control with center-weighted TTL metering. Optics and image quality are excellent. It was a real camera that you could take into the shower or down on any SCUBA dive.

The Nikonos V had a fairly unfriendly user interface for a camera that was designed for people breathing a limited air supply. To focus, you flip the camera over and stare at the front. Then you turn a dial until the correct distance is indicated. Then you flip the camera back over and take your picture.
Nikon fixed all of this with their Nikonos RS SLR, introduced with great fanfare in 1992. From the feature list, it looked basically like a water- and pressure-proof Nikon land SLR. Everything was automatic if you wanted it to be, the viewfinder offered super high eye relief (since the user was presumed to be wearing a SCUBA mask). There was an amazing 20-35 zoom lens and a tempting macro lens.
Warts? The Nikonos RS was priced at approximately $10,000 for a system, much more than a housed SLR. The camera would flood and require expensive repairs, which Nikon invariably blamed on user carelessness, despite the fact that these same people had been using the Nikonos V for many years with no problems. One photo.net reader who sold his said that what he hated most was the lack of neutral buoyancy: "I would hand the camera to my wife and then have to adjust my BC; I don't want a camera that becomes part of my weight system."
Nikon discontinued the RS system in 1996.
Nikonos V Gallery
Here are some snapshots from Hawaii with a Nikonos V and the standard 35mm lens.

Is it all worth it?
One of the best moments of my life was snorkeling in Kealakekua Bay on the Big Island of Hawaii. This is the bay where Captain Cook was worshipped as a God and subsequently stabbed to death by Hawaiians in 1779. I was about 1/2-mile out in the bay, drifting and look down at three reef sharks, each about six feet in length. They swam off suddenly and I looked up to see that a school of dolphins, perhaps 60 in number, had entered the bay. They were 200 yards away and I started swimming toward them. By the time I'd moved 10 yards, the school was all the way down at the other end of the bay (1/2 mile in the distance).
I gave up.
To my immense joy, the dolphins started coming back. They were heading straight toward me, occasionally one would leap but mostly I just saw 20 dorsal fins out of the water at a time (the other dolphins swimming underneath). My joy eventually turned to fear when I thought that perhaps a direct encounter with 60 bottle-nosed animals traveling at 30 miles-per-hour would not be pleasant. At the last minute, when the dolphins were no more than 15 feet away, they dove about 10 feet underwater and swam directly underneath. Some of them rolled on their sides to get a better look up at me. I snapped their picture with a Nikonos V.
When I got the images back, I found that the dolphins were only faintly visible on film. My eyes had adjusted to the blue light, but the film did not. The contrast between dolphin and water, dramatic to my eye, was very subtle.

Must you have a camera with you?
If you want to be a great photographer, the general rule is that you should carry a camera at all times. Competing with Christopher Newbert or Norbert Wu is a tall order, however. These guys go into the water every day year after year and wait.
It is difficult to take decent photos on land. It is difficult to go down underwater with tanks on your back and get back to the boat or beach alive. Don't feel compelled to combine these activities, especially if you're going on a dive that is challenging for you. There is nothing wrong with enjoying the underwater scene while you're privileged to be on vacation and underwater.
by Philip Greenspun