Get maximum sharpness

How do you get the sharpest possible photographs? Start with a sharp lens. To make sure you get one, try it before you buy it—even among big-name lens makers, you'll occasionally find a lens that's not quite right.

Each lens has a sharpest aperture. At wide apertures, various lens aberrations reduce sharpness, and at very small apertures, diffraction reduces sharpness. (You get more depth of field at small apertures, but you won't get optimum sharpness. And depth of field is just an illusion—the point focused on is sharp; everything closer and farther away is less sharp. Within depth-of-field limits, things appear acceptably sharp, but only the point focused on is truly sharp.) Generally, the lens's sharpest aperture is a stop or two down from wide open. Test it on your lenses.

Of course, a sharp lens won't produce sharp images if it isn't sharply focused. As good as today's autofocus SLRs are, they still miss sometimes. For maximum sharpness, focus manually on the most important portion of the subject. (If your images still aren't pinpoint sharp, you might have your camera checked—the camera can get out of alignment so the image isn't sharply focused on the film when it is sharply focused on the focusing screen.)

If the camera moves during the exposure, the image won't be sharp. So for maximum sharpness, it's a good idea to mount the camera on a sturdy tripod whenever possible. Even so, you can jiggle the camera when you press the shutter button, so use a cable release (or the camera's self-timer, if exposing at a decisive moment isn't important) to trip the shutter. An SLR camera's mirror creates vibration when it flips up out of the light path during an exposure, so lock it up ahead of time if your camera has this capability—this is especially important in high-magnification shooting, as in close-up work and when using super telephoto lenses.

Finally, use a sharp (i.e., slow) film for maximum sharpness. Slow films are sharper and finer-grained than faster ones, so use the slowest film that will let you get the shot.

If all this sounds like too much trouble, don't despair—today's cameras, lenses and films are capable of providing great image quality even if you don't follow all the just-cited rules.

Petersen's PHOTOgraphic

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Close-up photography is one of my favourite things to do. You can always find an interesting subject, whether you're on a trip to Africa or a jaunt through your own backyard. Plus, it's always the right time of day—you can take close-up images when the light is wrong for landscapes, for example. Even if the light is terrible, you can modify it with reflectors, diffusers or flash when you work up close. So I took the new Tamron SP AF 90mm f/2.8 macro lens into the field with great anticipation. This lens is an update of the old 90mm, not a whole redesign, so I expected it to perform well, too.

I enjoy photographing flowers, especially when I can get in close with minimal depth of field. By choosing to focus on a very precise, but also very limited area and letting everything else go blurry, you gain an ethereal, colourful and sensual look in the images. Since depth of field is very shallow anyway when you get close, this technique simply uses that "problem" as a creative tool.

The minimum-focus technique works best with a wide-open f-stop and a telephoto lens. But you need the sharp areas to be sharp and the out-of-focus areas to have a pleasing gradation when the lens is at its maximum aperture. Not all lenses can do this. I actually bought my first true macro lens (a lens designed for optimum sharpness up close) so I could get excellent sharpness when the lens was used this way.

The Tamron delivers. Sharpness is excellent and the out-of-focus areas have a wonderful quality to them. I was really pleased with what I got in my images. One thing you notice very quickly when shooting with different lenses up close is that "out of focus" isn't a simple "either it is or it isn't." Different lenses give different looks. This 90mm looks great for both the in- and out-of-focus areas. When you need more depth of field or sharpness from near to far, you can stop this lens all the way down to f/32 for superb results.

This incarnation of the Tamron SP AF 90mm still uses a lens construction of 10 elements in nine groups, but it's both smaller and lighter than the old version, with a 2.7x3.8-inch size and a 14.2-ounce weight. The lens' size makes it easy to hand-hold for the sharp/soft photos shown here, as you usually shoot at such high shutter speeds that a tripod won't make any difference. If you stop down to f/11 or so, use a tripod, as close-up work with telephoto lenses is highly susceptible to camera movement blur.

A very nice new feature of the lens is a focusing clutch, which engages and disengages the focusing gear from the lens focusing ring. Often, when shooting close-ups, you must shoot with manual focus. This is absolutely critical for the minimum depth-of-field technique as you must carefully select the exact spot you want your sharpness to be. Often, the autofocus will choose something inappropriate. With this lens, you can bounce back and forth from manual to autofocus by just sliding the focusing ring forward or backward. The lens takes 55mm filters and can focus to 11.4 inches for 1:1 magnification. It's available in Canon, Minolta, Nikon and Pentax mounts.

Get most out of your wide-angle zoom lens

What can a wide-angle lens offer you? For starters, a 35mm lens covers roughly twice the area of a standard 50mm lens, and a 17mm lens covers about nine times the area of a 50mm. That's significant when you find yourself in tight quarters or in front of a spectacular landscape - you'll capture much more of the scene.

Wide-angle lenses also offer you the ability to emphasize foreground elements while still recording the surroundings. The closer you get to your subject, the more you'll notice the perspective distortion that wide-angles offer. Objects close to the lens appear much larger in relationship to objects farther away, drawing attention to foreground details that might get lost in a photo taken with a standard or telephoto lens. Most wide-angle lenses also have short minimum focusing distances, so you can take advantage of the perspective distortion without losing focus.

Wide-angle zooms used to be a trade-off. They were either prohibitively expensive, or the quality of the lens wasn't very good. That's changed - modern manufacturing techniques have allowed lens makers to use technology such as aspherical elements to produce high-quality wide-angle lenses at a fraction of the cost of previous models. That's really good news because of the benefits that a zoom model offers over a prime lens:

Another benefit: As you push toward the ultra-wide end of the range, wide-angle images have a unique look. You'll find yourself considering compositions that you wouldn't have even conceived without the wide-angle perspective, and you'll be capturing scenes that elude standard lens-bearing shooters. The following tips will help you get more out of your wide-angle photography:

Tamron's 14mm rectilinear-corrected lens 
challenges more photographers to try 
the super-wide experience

Wide-angle lenses are typically purchased when a photographer feels the need to capture more of a scene on film, although they also strongly affect such things as perspective, color and depth of field. The idea of capturing "more" works down to a focal length of about 20mm for the average 35mm photographer. Go beyond that and some things change quite dramatically, offering much more than what we usually expect with a wide-angle.

At 14mm, the world in front of your camera changes hugely! We don't normally see the landscape with this lens' unique combination of angle of view (114 degrees) and perspective. It can give such an amazing view of the world, besides letting you photograph in very small spaces. However, this extremely wide angle of view now includes so much that foregrounds become a huge challenge. If you're not careful, you'll even end up with your feet or other body parts in the image (plus a tripod leg or two). And the background recedes so far back that it can be hard to see.

Tamron's new SP AF14mm f/2.8 aspherical lens offers all of the magic of a super-wide with perfect rectilinear correction. Once you shoot with this dramatic-looking lens (that first lens element is amazing), things pretty much look like a normal photo on the surface - excellent sharpness, crisp colors and a snappy image brilliance. But "normal" changes when you actually look at the strange world uncovered by the focal length.

The SP AF14mm lens has 14 elements in 12 groups (that's a lot of glass), including two hybrid aspheric lenses. The aspheric lenses actually make this lens possible, correcting aberrations that made such a focal length extremely difficult to make in the past. Lenses of this focal length were very, very expensive (if available from a given manufacturer at all).

Don't confuse extreme wide-angle effects with aberrations, however. All rectilinearly corrected (meaning straight lines are straight, not curved) super-wide lenses stretch photo elements near the corners. They have to do this stretching in order to make the lens "see" in a rectilinear way (otherwise, we'd see some natural curvature to straight lines - the curves look wrong to our eyes, but are actually true to perspective at this viewing angle).

This gem from Tamron features an f/2.8 maximum aperture for ease of shooting in lower light levels. A maximum aperture of f/2.8 seems fairly fast and, on a normal lens, would offer some different depth-of-field effects. But in the magical 14mm world, depth of field is deep at every f-stop. Even at the lens' minimum focusing distance of approximately eight inches, depth of field is far more than the couple of inches you'd normally expect.

What the f/2.8 does offer is more speed so you can use a faster shutter speed and gain more brightness to the viewfinder so you can compose more easily when the light levels drop. Focusing can be a challenge because of the great depth of field, so it often helps to simply estimate medium and far distances and set them manually.

I had only shot wide-angles this size a few times before I had a chance to work with Tamron's new lens. Putting on a 14mm is a truly amazing experience. It makes a 28mm lens seem like a telephoto. I really enjoyed using this lens in the field. I love the perspective effects it gives, as well as its extreme wide angle of view, especially up close. It's incredible to move within a foot of a group of flowers, for example, and get a view that's looking straight down and straight ahead - at the same time. And once those photos were taken in the field, the results back at the light table were superb.

Although OP is dedicated to the outdoor photograph, our readers sometimes find themselves in tight spaces, especially when traveling. The SP AF14mm would be a wonderful travel lens for the photographer who likes to shoot foreign architecture. It's so wide that you can often get in front of visual obstacles and still see the subject. Realize, though, that perspective is extreme and can give striking, although sometimes eccentric results with architecture.

The Tamron SP AF14mm lens uses an internal focusing mechanism and stays fairly compact, with dimensions of 3.4x3.5-inches and a weight of 32.3 ounces.

Vivitar 100mm f/3.5 MACRO

For aspiring macro shooters on a tight budget, Vivitar's 100mm f/3.5 Manual Focus Macro lens is a great choice. It doesn't focus down to 1:1 on its own (it goes to 1:2), but it comes with an adapter that gives it 1:1 capability, performs well, and costs much less than the other 100mm macro lenses. It comes in mounts for Canon, Minolta, Nikon, Olympus, Pentax, Ricoh and Yashica-Contax manual-focus SLRs. Specs include five elements in four groups, a minimum aperture of f/22, a minimum focusing distance of 264mm (measured from front of lens), an economical 49mm filter size, a diameter of 68mm, a length of 71mm, and a weight of just 257g.  There's also an autofocus version for Canon EOS, Minolta Maxxum and Nikon AF SLRs.