New Orleans photography » A Big Easy photo blog

Remember, we agreed that you’re looking to create images that are first and foremost in-focus and not too bright (overexposed) or too dark (underexposed.) Simple. First learn the rules, then learn to break them.

Lenses come in various focal lengths, the length or distance from the front of the lens to the camera’s sensor measured in millimeters.

Some lenses are primes (one focal length) and others are zooms (various focal lengths). Many photographers swear by prime lenses to achieve tack-sharp focus; other photographers swear by zoom lenses for versatility. I am both. If I’m looking to take a close up of a spider on the veil of an 8-year-old witch, I use my fixed-focal-length prime 105mm macro (it’s also considered a telephoto lens; more on that in a minute).

Nikon D300, 105mm prime lens, f5.6 @ 1/250 second, ISO 200.

My workhorse lens, the one I grab most often, is a 28-70mm f/2.8 zoom lens (zoom because it covers all focal lengths from 28 through 70, wide angle to telephoto because of the field of view it covers. Keep reading.) This lens doesn’t produce quite the tack-sharp images as my primes, but the tradeoff I get is versatility. If I’m shooting portraits of a 1-year-old, who by definition movesveryfast, it’s incredibly helpful to be able to change the focal length of my lens in one quick movement from a 70mm to a 28mm and everywhere in between as she starts to run toward me — AND, because this lens is f/2.8 at any focal length, I don’t have to adjust my settings mid-run. Can’t do that so easily with a telephoto lens, a prime lens or a zoom lens with variable aperture. When working with children or in fast-changing environments, switching lenses can mean missing the shot. The flexibility and versatility of a zoom can be a gift to photographers.

My 28-70mm is a wide-angle to telephoto zoom lens (clue: two numbers with a dash, indicating those focal lengths and everything in between.)  My 105mm is a “prime” telephoto lens. Focal length numbers range from fisheye to wide angle to normal to telephoto. A fisheye lens has a field of vision covering up to 180 degrees; wide angle is between fisheye and normal; a 50mm lens is considered “normal” because it sees roughly the same field of view as the human eye; and a telephoto lens has a narrower field of view and a magnified image (think spotting scopes or binoculars.)  Telephoto lenses are notorious for beautiful bokeh (the visual quality of the out-of-focus areas) and compression of distance.

Here’s a chart to help you visualize focal lengths:

Here’s an example of my 28-70mm lens shot at 28mm and again at 70mm without changing the distance from me to the subject:

Nikon D700, 28-70mm lens at 28mm, f4 @ 1/1250 second, ISO 400

Nikon D700, 28-70mm lens at 70mm, f4 @ 1/1250 second, ISO 400

If you are a realtor looking to photograph the interior of homes, or a pilot looking to photograph your co-pilot inside a cramped flight deck, or a tourist looking to fit the Washington monument inside your frame, you’ll need a wide angle lens. 16mm or 28mm for example; the drawback to wide angle lenses is some visual distortion. (There is software that can fix this.) Traditionally, wide angle lenses are not considered ideal for portraits. (Although, we’ll discuss this later in “first learn the rules, then learn to break them.”)

Nikon D300, 16mm f/2.8 prime lens at f5.6 @ 1/2500 second, ISO 200

Nikon D300, 16mm f/2.8 prime lens at f5.6 @ 1/50 second, ISO 800

Most portrait photographers start out at 105mm, partly because there is no unflattering distortion to facial features and partly because of this:

bokeh
noun Photography
the visual quality of the out-of-focus areas of a photographic image, especially as rendered by a particular lens : a quick, visual survey of the foreground and background bokeh of a variety of lenses.
ORIGIN from Japanese.

Nikon D200, 105mm f/2.8 prime lens at f3.2, shutter speed not recorded, ISO 100

If you didn’t know what bokeh was but you know you love images where people are sharp and the background is really, really blurry, then you know you should be looking for a telephoto lens.

There are some instances in which you can’t physically move closer to your subject, so you need a lens that can take you there. If you are looking to photograph your son on the football field, or your daughter at a swim meet, or the Pope who drives by in the Pope Mobile while you stand behind police barricades from 25 feet away, you’ll need a telephoto lens to magnify the image you want to shoot. Examples of telephoto focal lengths are 85mm, 105mm, 200mm, 400mm. The numbers go even bigger than that — Sports Illustrated photographers use behemoths from the sidelines. If I were out shooting 300lb. men trying to kill one another, I’d use behemoth too, as my favored 28-70mm would put me right in the crossfire trying to get an image (if I didn’t get thrown out of the game first for walking onto the field.)

Following is an example of shooting from the edge of the pool with my 70-200mm telephoto zoom, first at 70 and then at 200. Note: my D700 is a digital full-frame; so I lose the times-1.5 factor on focal length. 70mm is in fact 70mm. Also note that I’m at ISO 400; when shooting sports, even in sun, I bump up my ISO to 400 to give me a faster shutter speed so I can freeze action — totally unnecessary for this shot, but I had my settings ready in anticipation of shooting swimmers and divers.

Nikon D700, 70-200mm f/2.8 zoom telephoto lens at 70mm, f5 @ 1/1600 second, ISO 400

without moving, this is the same shot as above only I changed the focal length of my lens to 200mm. notice I had to adjust my shutter speed to compensate — longer focal lengths suck up more light. if my shutter speed starts to go slower than 1/250 with this lens at 200mm, then I need to start looking at bumping up my ISO.

Nikon D700, 70-200mm f/2.8 zoom telephoto lens at 200mm, f5 @ 1/800 second, ISO 400

Okay okay okay, I get it you say. I understand focal length. Next lesson.

But wait — one more thing. There a really, really important exposure equation that relates to focal length, and if you don’t learn it straight-up, you’ll spend a lot of money on a telephoto lens and come back asking why your pictures are consistently blurry. Here’s the magic equation to keep in mind:

Your shutter speed must be equal to or faster than your focal length to avoid camera shake. What does this mean? If you are hand-holding your camera with a 200mm telephoto lens, you must use a shutter speed of 1/200 or faster to avoid blurry images. Handholding a 400mm lens? Shutter speed must be 1/400 or faster. Handholding a 50mm lens? Shutter speed must be 1/50 or faster. Of course, you can use a tripod or a monopod to keep your camera still to compensate for this law (notice the Sports Illustrated photogs on the sidelines with their monopods, partly for this reason.) This might not make sense right away, but when we get to shutter speed it’ll start to click (pun intended?) For now, just remember this:

Focal length affects shutter speed choices.

Buying tips: Remember, you can’t put a Canon lens on a Nikon body or a Pentax lens on a Sony body. Lens mounts have electronic connectors that relay information from body to lens. There are some third party lenses that are built specifically for Nikon or Canon bodies, Sigma lenses, for example. But again, you can’t put a Sigma lens for Nikon mount on a Canon body. You can save money on third party lenses but be sure to do your research to make sure your lens is compatible with your camera body.

Some digital SLRs have smaller sensors than others. Check your manual. If your digital SLR has a “full frame” sensor, then the focal length of your lens will be equal to the focal length number printed on the lens and you can skip to the next paragraph. (85mm = 85mm on a full frame body, for example.) I wasn’t always shooting with a full frame digital SLR, and the way I got around this annoyance was to multiply the focal length of the lens by 1.5 to determine roughly how a lens would perform on my camera body. So my 85mm prime lens suddenly became equal to 127.5mm, which means my 200mm was suddenly 300mm. This is GREAT if you’re looking to make telephoto lenses more telephoto without spending money! However, this same law can prove bothersome if you work a lot in the fisheye or wide angle range. Some manufacturers make digital lenses designed specifically for digital bodies that are not full-frame. I don’t personally own any of these lenses, so I can’t show you any pictures from them.

Okay, so now you have some rough guidelines for choosing the focal length of your lens. You know you need a roughly wide angle/normal/telephoto lens for the kind of images you want to shoot, and you might try to find a zoom that could kill two birds with one stone. You start looking for lenses in respective categories. And now you’re confused again, because after the focal length numbers, there are ADDITIONAL numbers stamped on each lens, and you don’t know what they mean other than to make some of the lenses ghastly more expensive than others even though the focal length is exactly the same. What gives?

[return to the PHOTO 101 Table of Contents]

Nikon D200, 70-200mm lens at 105mm, f2.8 @ 1/1250 second, ISO 400

Q: What kind of camera do you have? Do you use Nikon or Canon? Do you shoot .jpg or RAW? Do you use Bridge or Aperture or Lightroom?

A: Nikon or Canon, digital or film, .jpg or RAW … all are just tools in a photographer’s toolbox. The question I am most often asked is best answered in “Letters to a Young Poet” by Rainer Maria Rilke.

That’s how I used to answer this question.

And then I would get:

Q: What does that mean?

A: A young poet sends his poems to Rilke and asks for Rilke’s critique. This is but a glimpse of Rilke’s answer to the young poet:

“You ask whether your verses are any good. You ask me. You have asked others before this. You send them to magazines. You compare them with other poems, and you are upset when certain editors reject your work. Now (since you have said you want my advice) I beg you to stop doing that sort of thing. You are looking outside, and that is what you should most avoid right now. No one can advise or help you – no one. There is only one thing you should do. Go into yourself. Find out the reason that commands you to write; see whether it has spread its roots into the very depths of your heart; confess to yourself whether you would have to die if you were forbidden to write. This most of all: ask yourself in the most silent hour of your night: must I write? Dig into yourself for a deep answer. And if this answer rings out in assent, if you meet this solemn question with a strong, simple “I must,” then build your life in accordance with this necessity; your whole life, even into its humblest and most indifferent hour, must become a sign and witness to this impulse.”

Q: Uh, yeah, okay. So, does that mean Canon or Nikon?

A: It means it’s not the camera! It wasn’t the quill that produced Shakespeare’s timeless works. It’s not a camera that takes great photos — it’s the photographer.

Q: Oh. So…what kind of lens should I get?

Since I keep getting the questions, I’ve decided to expand my answer. It’s probably going to take me a couple of posts to get it all in. I plan to include photos (how better to illustrate my point?) and a “cheat sheet” that I hand out to students when I’m teaching classes.

The bottom line is, if you don’t know what you’re trying to achieve (you being the photographer), how can you possibly expect your camera to?

Google “Nikon vs. Canon” and you’ll come up with thousands of forum discussions and reviews.  Both companies make great cameras (and, perhaps more importantly, great lenses!)

My very first camera was a Canon. My current point-and-shoot (PAS) is a Canon. My digital SLR body is a Nikon. I’ve owned at least a dozen SLR camera bodies, both digital and film, since I was a college freshman, but there’s one very good reason I continue to buy Nikons: I have Nikon lenses. I bought my first lens, a 50mm, when I was 18. I’m still using that lens. (That’s an inadvertent yet relevant plug for Nikon; newer bodies work with old lenses. A Nikon lens from 1959 can be used as-is on the digital Nikon D40. This is a general truth, please do the prudent thing and check specifically with your lens and/or body for compatibility before purchasing.)

Sometimes, when Canon outpaces Nikon in a particular heat, I toy with the idea of switching over; but I’ve found if I hold out long enough, Nikon will pull ahead again as surely as Canon will catch up and give Nikon a run for its money. There are a few details where Canon outshines Nikon and few others where Nikon outperforms Canon, but the bottom line is that they are fiercely competitive companies and both produce a good product.

If you’re already invested in lenses for Nikon or Canon, the questions of whether to buy a Nikon or Canon digital SLR is best answered first by whether or not those particular lenses are compatible.

If you’re not already invested, flip a coin.

Q: What kind of lens should I buy?

A: What kind of pictures do you want to take?

Because here’s the deal: there is no magic pill that will reverse the effects of aging, remove unwanted pounds without diet or exercise, grow you an instant billionaire overnight by working from home. It’s the same thing with photography! There is no PAS or body-lens combo that will deliver you the images you want. Cameras don’t shoot pictures; photographers do. Cameras aren’t photographers; people are.

This is why we have to start by breaking things down into a crash course in photography. There are many factors to creating one image, and choosing the right gear to create specific images requires knowledge of such factors.

Q: Will it be long and tedious and involve a lot of math?

A: Of course not! I’m an English major, so math is guaranteed limited (unless you want to step it up a notch in the comments. I’ll moderate, but I’m not going to calculate.) If you wish you knew more but don’t really have time or energy to dig through mounds of information on your own, I’ll boil it down here.

Q: What if I already have some gear and don’t want to buy more?

A: Then your best option is the same as everybody else’s: learn to use the gear you already have!

I’ll file the series in “Photography 101″ so you can come back anytime and find all the installments (after they’re written!) by clicking on that category thread or by clicking on the Table of Contents.

So before we begin, let’s agree, for the sake of simplicity, that you’re looking to create images that are first and foremost in-focus and not too bright (overexposed) or too dark (underexposed.) Simple. And you’re looking at digital SLRs (because if you’re looking for a PAS, CNET reviews would suffice.) Send me your questions and we’ll get started…