Lens (optics)

What Are Prime Camera Lenses, and Why Would You Use Them?

In photography, there are two types of lenses: zoom lenses and prime lenses. Zoom lenses cover a range of focal lengths. If you’ve just bought a new DSLR, the kit lens that comes with your camera is almost certainly a zoom lens; most come with an 18-55mm lens, which means that lens covers every focal length between 18mm and 55mm. A prime lens, on the other hand, covers just one focal length. A 50mm lens is just a 50mm lens.

If, however, the 18-55mm lens that comes with your camera can be used as a 50mm lens, why on earth would you get a dedicated 50mm prime lens?

Prime Lenses Perform Better

Focal length is just one of the characteristic of a lens; the other important one is aperture. Just knowing the focal length of a lens doesn’t tell us a whole lot about how it will perform in the real world.

This image, like all the others in the article, was shot with a prime lens. For this photo, I used a $150 50mm prime. Even a $2000 zoom lens would have struggled to get this shot.

Focal length determines the field of view and apparent magnification of the lens, while aperture determines the depth of field and low light performance. All 50mm lenses will share the same field of view and magnification, but they can have vastly different apertures.

Looking back at our 18-55mm kit lens, at 50mm it probably has a maximum aperture of f/5.6. This isn’t especially wide, and won’t make pleasing portraits or perform great in low light. The 50mm prime lens, however, will have an aperture of f/1.8…

What Is a Telephoto Lens?

Telephoto lenses can be incredibly useful, but how is it different from other lenses, and when should you use it?

What Is a Telephoto Lens?

A telephoto lens is a lens that appears to magnify distant objects. To do that, they need to have a focal length longer than that of a normal lens, or a lens that approximates the optical qualities of the human eye. A normal lens has a focal length of between 40mm and 58mm on a full frame camera so any lens with a focal length longer than 60mm can be considered a telephoto lens. The longer the focal length, the more magnification there is.

The most common telephoto zoom lenses have a focal range of 70mm to 200mm. Any lens with a focal length longer than about 300mm can be considered a super telephoto lens as well.

On a crop sensor camera, telephoto lenses are those with a focal length longer than about 40mm, although the magnification will be minimal until about 50mm.

Let’s look at this in action. This photo was taken at 50mm, a normal focal length, on a full frame camera. The photo appears pretty similar to how things look with your eyes. The other photos were all taken from the same spot with a crop sensor camera; I don’t have a long enough full frame telephoto to really make the point clear.

This photo was taken at 45mm using a crop sensor camera. The full frame equivalent focal length is 72mm. You can see how the image is a little tighter on the car.

This photo was taken at 85mm, equivalent to 136mm on a full frame camera. Now the car totally fills the frame.

This photo was taken at 135, equivalent to 216mm on a full frame camera. We’re incredibly close to the car compared to the normal photo. It’s impossible to fit the whole thing in the picture.

How a Telephoto Lens Affects Your Images

The main effect of telephoto lenses is that, like a…

Hubble Space Telescope Reveals Glittering Galaxies Of New Stars

These six Hubble Space Telescope images reveal a jumble of misshapen-looking galaxies punctuated by exotic patterns, such as arcs, streaks and smeared rings. The images have been magnified by an effect called gravitational lensing. Some of these odd shapes may have been produced by spectacular collisions between faraway galaxies.

Using “natural magnifying lenses in space,” the acclaimed Hubble Space Telescope has photographed amazing close-up glimpses of what NASA refers to as “the universe’s brightest infrared galaxies.”

“The galaxy images, magnified through a phenomenon called gravitational lensing, reveal a tangled web of misshapen objects punctuated by exotic patterns, such as rings and arcs,” NASA says. “The unusual forms may have been produced by spectacular collisions between distant, massive galaxies in a sort of cosmic demolition derby.”

It’s not just the glitz, glamour and garish-looking spectacle of the galaxy clusters. These galaxies are producing more than 10,000 new stars a year. And their glow is so bright in the infrared range that they shine with the intensity of 10 trillion to 100 trillion suns.

“We have hit the jackpot…

What Is a “Normal” Camera Lens?

The lens you use has a huge effect on how your photos look. A wide-angle lens will give you a much greater field of view, while a telephoto lens will magnify distant objects. These aren’t perfect, though: the photo will look like it was taken with whatever lens you used.

There are weird optical quirks like barrel distortion with wide-angle lenses—straight lines appear to curve—and compression with telephoto lenses—objects appear much closer together—that come with using different lenses.

So what do you do if you want a photo to look something like the real world? For everything to appear how you see it in front of you and not strangely distorted by your lens? That’s when you use a “normal lens”.

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What Is a Normal Lens?

A normal lens is one that best approximates the optical characteristics of the human eye. In other words, the photos taken with a normal lens look closest to how we see the world. This has nothing to do with aperture, but is entirely dependent on the focal length of the lens.

It’s difficult to perfectly compare human vision to cameras; both work in very different ways. Our eyes aren’t the equivalent of any specific lens. Instead, there are a range of focal lengths that will create photos that look roughly the same. There will always be differences, but the photos shouldn’t look distorted like a wide-angle or telephoto photo can.

On a full-frame camera, a normal lens is considered to have a focal length of 50mm. This was set by the creator of the Leica camera system, Oskar Barnack, pretty much arbitrarily. In reality, any lens with a focal length of between about 40mm and 58mm will look roughly like how things appear to your eyes.

On a…

New Process Will Allow You to 3D Print Glass on Demand

The surge in affordable 3D printing in recent years has allowed hobbyists to craft everything from customized toys to hair to prosthetic duck feet, with the only limit being the creator’s imagination. Now, researchers in Germany are close to achieving a technique that could revolutionize both 3D applications and glassmaking by giving us the power to 3D print glass.

In a study published in Nature this week, Karlsruhe Institute of Technology (KIT) investigator Dr. Bastian Rapp presented a way of manufacturing a “liquid glass” that can be manipulated with 3D printing software and then heated until it’s a useful solid. (Normal glass consists of melted sand made from sheets in molten tin vats.) By making the glass dispensable through 3D printing nozzles, Rapp believes we’ll soon be able to 3D print glass that’s of sufficient quality for lenses, mirrors, and even drinking cups.

Previous attempts to conceive of a new way of glass production via 3D printers haven’t resulted in glass smooth enough for…

Snapchat World Lenses Are the Next Step in Augmented Reality

Since it was founded in 2011, Snapchat has used cutting-edge technology to successfully set itself apart from other photo-sharing services. The app’s latest feature, Snapchat World Lenses, integrates colorful, 3D objects into real-world scenes captured on your smartphone.

As The Verge reports, Snapchat World Lenses were introduced on Monday, April 18. This is the latest experiment with augmented reality we’ve seen from the mobile app. As Snapchat says in a statement:

“We launched Lenses over a year ago as a whole new way to express ourselves on Snapchat. Since then, we’ve become puppies, puked rainbows, face-swapped with our best friends—and begun to explore how Lenses can change the world around us.

Today, we’re adding new ways to use Lenses.”

Unlike most of the app’s high-tech filters, Snapchat World Lenses aren’t designed for faces. They’re meant to be plopped down anywhere in the space being recorded on your phone’s rear-facing camera. That’s where the augmented reality element comes in: The 3D objects behave as if they’re physically in front of you. Move your…