Lenses For Panoramics

Perspective Control In Panoramics • Tripod Shopping • Megapixel Printing • Is What You See, What You Get?

Tech Tips: Lenses For Panoramics

Perspective Control In Panoramics

I’m interested in trying panorama landscapes. In a class I recently took, the instructor said that the only way to get a good panoramic landscape is to use a PC (perspective control) lens. It’s a lot of money! Is there another way?
Participant at Photoshop World
Boston, Massachusetts

It doesn’t have to be so hard! It’s true that there are advantages to using a perspective-control lens when shooting panoramics, but in most situations, it’s completely irrelevant. A perspective-control lens lets you keep straight lines unbowed. But if your horizon is roughly centered in your frame or you don’t have a strictly defined, straight-line horizon in your landscape, the potential for bowing doesn’t matter.

A panoramic rendition of a flat sea or a Kansas prairie might be affected if you’re shooting with your camera aimed up or down on the scene. If your composition includes mountains in the distance, a jagged line of foliage or no horizon at all, don’t worry about taking it with a normal lens. Level the camera side to side, overlap the shots by about 20 percent (50 percent if you’re using a wide-angle lens), and enjoy taking panoramas with the equipment you already have.

Spend the money on a great software program, such as ArcSoft’s Panorama Maker 4 Pro (www.arcsoft.com) or the new Photomerge feature included in Adobe Photoshop CS3 (www.adobe.com) to make putting your panoramic images together a breeze. And if you’re into fixing it in the computer, look at DxO Software (www.dxo.com); it’s a nifty program that, among other tricks, straightens a bowed horizon.

The advantage of a Canon tilt/shift or Nikon PC/tilt/shift lens is that once the lens is leveled along its axis and to the horizon, the front elements can be raised or lowered to change the vertical or horizontal framing without changing the position of the camera. This can be important for images with a defined horizon. With a normal lens, if the camera is pointed up to frame a lot of sky, the finished panoramic series will produce a slightly concave (bowed downward) horizon. If the lens is pointed down and the horizon placed low in the frame, the result across the series will be a slightly convex horizon (bowed upward). The PC or tilt/shift lens eliminates this curvature of the horizon when the horizon is placed extremely high or extremely low within the frame.

The panorama image shown here was taken in Yellowstone National Park with a 100-400mm Canon zoom lens set to 100mm. It’s a series of eight images, four across the top and four across the bottom. It was composited in the new Panorama Maker 4 Pro. There’s no horizon in the image, so I wasn’t concerned about any bowing of the horizon. I’ve taken panoramas with lenses from 1000mm to 16mm wide-angle. And, yes, I occasionally use my tilt/shift lenses.

Tripod Shopping

What features do you recommend when shopping for a new tripod and panhead? I’m a smallish woman and mainly take landscape and macro photographs.
G. Montgomery
Dallas, Texas

This is the perfect time for you to invest in a new tripod because there are so many choices in different price ranges that are perfect for you. You need to look for a tripod that’s both lightweight and sturdy—something that carbon fiber gives you. Even though carbon-fiber legs are light in weight, they’re sufficiently rigid to handle telephoto lenses up to 400mm.

You need a tripod that can place your camera low to the ground. This last feature is important to macro photographers. Another useful feature is a center column that can be removed and placed horizontally in a configuration that improves its macro capability. Flexibility in positioning the legs in many ways can also help bring the camera and lens close to the ground.

In my opinion, the optimal choice for the types of photography you mention is one of the tripods with new leg-locking mechanisms, such as Gitzo’s G-lock. These lock and unlock with very little effort. This completely eliminates the problem of legs that collapse or are overtightened, which many women especially find frustrating.

An equally important part of your camera/lens support system is the head. The choice of most professional nature photographers is a ballhead because you can quickly position it and lock it into place with a single knob. A quality ballhead will have a quick-release top and a panorama base to allow you to smoothly rotate the camera/lens combination. Beware of low-priced tripods and ballheads that might seem okay for your endeavors. While better tripods and heads can be a bit pricey, they’ll serve you well for a photographic lifetime. Sometimes, you really do get what you pay for.

> Visit www.geolepp.com.

Megapixel Printing

Using an 8-megapixel camera, what are the largest prints I can reasonably make?
B. Johnson
Via the Internet

There are a lot of variables here, starting with the kind of camera you’re using. All megapixels aren’t created equal. A point-and-shoot or advanced compact digital camera typically has a 5.32×7.18mm sensor. That’s a lot of tiny pixels packed together on a very small surface, and the potential for noise and image degradation is noticeably greater when prints are enlarged from these cameras.

At the other end of the 8-megapixel scale, the midrange digital SLRs have a sensor of approximately 23x15mm—nearly 10 times the surface area of the smaller sensor. The pixels are larger, allowing better light-gathering capability and better color, minimizing noise. The files captured with these cameras are capable of producing much larger prints.

But it’s not only pixels that matter. The maximum print size is a subjective decision for each photographer, but I’d set a maximum of 13×19 inches from an excellent capture (sharp, good color, proper exposure and controlled contrast) taken with the smaller-sensor cameras. A capture from an 8 MP D-SLR with the same excellent file qualities is capable of a print in the 16×20- or 17×22-inch size. Of course, these results require that the prints are being made on a photo-quality inkjet printer, with proper media profiles. You can extend the size if you print on a watercolor or canvas media because less detail is required on these surfaces.

Is What You See, What You Get?

I’ve heard that the information I see on the LCD on the back of the camera isn’t very accurate when compared to the actual image file captured. Is this true, and if it is, how do I get better information?
B. Williams
Via the Internet

What you’ve heard is right. That little LCD isn’t capable of giving you an image that matches the file. That said, the newer 2.5-inch LCDs can give you most of the information you need to determine whether your capture is well composed, sharp and properly exposed. It’s this last feature that requires some extra attention when you’re working in the field.

The image on the LCD can give you reasonably accurate exposure information at a glance if you first keep the brightness of the LCD to its middle setting (usually this is the default). Some photographers set the brightness up when working outside so that they can see the image better. But this gives a false sense of the brightness of your image capture.

You can circumvent this problem by throwing a dark cloth over your head and pretending you’re shooting large-format. No, just kidding. You can get the HoodLoupe by Hoodman (www.hoodmanusa.com), a handy little gadget you hang from a strap around your neck. It fits over your LCD and slightly magnifies it, letting you get a clear view even in bright sunlight.

The LCD can also tell you whether you’ve overexposed the highlights; you’ll see a flashing highlight-warning that indicates blown-out areas that have no detail. The “blinkies” reflect the camera’s JPEG setting, so if you’re shooting JPEGs, you can believe what you see. But if you’re shooting in RAW, you’ll need to make some adjustments in your camera software to get a correct “blinky” reading. Setting the JPEG contrast parameter to its lowest setting will give you an accurate reading in RAW.

Finally, learn to love—and believe—your histogram. A histogram that’s piled up against the left, or black, axis is telling you there are no details in the shadows of your image. A high pixel count against the right, or white, axis, says you’re overexposed and have no detail in your highlights. Unless you’re shooting coal or a pure white sheet of paper, you want to keep your histogram off those two edges. Check it, and adjust your exposure as necessary to move the captured data away from either end.

The LCD may not give us as perfect a rendition of our images as we can see on our computers, but it gives us enough information so that there’s no excuse for bringing home images that lack the critical elements of sharpness, composition and exposure. One of the great benefits of shooting digital is the ability it gives us to make our corrections in the field and to get the best possible image file before we begin to optimize it in the computer.

> Visit www.geolepp.com.

One of North America’s best-known contemporary outdoor and nature photographers and a leader in the field of digital imaging and photographic education, Lepp is the author of many books and the field editor of Outdoor Photographer magazine. One of Canon’s original Explorers of Light, Lepp finds inspiration in advancing technology that fuels creative innovation and expression of his life-long fascination with the natural world.