The Tamron 28-200 was just the tip of the iceberg to come. Other independent lens manufacturers hopped onto the bandwagon and came up with their own 28-200. The new designs are compact due to new optical designs and innovative cam mechanics which allowed them to squeeze such long focal zooms into a compact body. The innovation of molded aspherical elements over the conventional elements made possible the great optical quality at a reasonable price. Aspherical elements are used to eradicate distortions of bright points of light, rendering them as points of light instead of comas. Traditionally, aspherical elements were ground from glass blanks. Now, special acrylics are molded over the normal elements to create aspherical elements. This process is cheaper and easier than the traditional grinding process. Technological advances also allowed for groundbreaking mechanical innovations, such as Tamron's triple-cam to shorten the physical size of the lens. Tokina's newest kid on the block is the 35-300mm. Sigma has it's 150-500mm. And you can expect to see more of such superzooms in the future. But why the fascination with superzooms ? And what are the compromises we have to make ?

Appeal of superzooms

It is easy to see the appeal of superzooms. They are everything that a budding photographer could ask for. They cover such a wide range, from the wide 28mm to the far-reaching telephoto of 200mm, in one single lens ! The photographer need only buy one lens, and he can confidently face any photographic situation which may await him. And he can save money by buying just one lens, instead of several to cover the range of the superzoom. Also, he need not worry about changing lens.

All of the above are indeed true statements about superzooms. They:

• cover a wide-range of focal length
• eliminates the need to change lenses
• are often high in optical performance
• are convenient
• saves space and weight

But since they're so darn good, why ain't everyone dumping their lens for one of these wonder lenses ? As you might have already guessed - there are compromises…

Distortion

Although the superzooms contain aspherical elements, they do not get rid of all distortions. Superzooms are usually plagued by bad distortion at both extreme ends. Such distortions include barrel and fisheye. Modern superzooms are getting better, but then your expectations always go one step ahead ! The distortions are usually not very evident in normal photos of landscape and portraits, but may be critical if you're shooting architecture or any other stuff with obvious straight lines. So if you don't shoot architecture or brick walls, the distortions usually don't count enough to matter.

Filter size

This is probably the most critical factor to stop you from buying a superzoom. When you want to buy filters for your lens, you have to specify the lens filter diameter. Here are the filter diameters for some superzooms:
 
 
 

Now, consider that the diameter of a 28-70mm or 70-210mm is only around 58mm, the superzooms have filter diameter several sizes bigger than them. In fact, they need the one of the biggest sized circular glass filters that manufacturers make, typically 72mm. The Sigma 150-500mm needs a filter size of 86mm, which doesn't exists for most filter manufacturers !!! Such huge filter sizes such as 72mm usually will cost 2 times or more the price of a 58mm filter.

If you thought you're saving money by buying a superzoom, think again. The hidden costs is in the filters. Even if you're willing to spend the money, the filter may not exists in the larger size.

AF speed

Most of the superzooms exhibit excruciatingly slow autofocusing speed. They have helluva lot of noise, and painfully whines and turns to the correct focus.

Aperture

The aperture of the superzooms are usually a tad "slower" than the normal zooms. For example, the 28mm end may start at f/3.8 for a superzoom, but at f/3.5 for a 28-70mm zoom. A 35-70mm zoom starts at f/3.5, while the Tokina 35-300 starts at one stop slower (f/4.5). A 70-300 lens ends at f/5.6, the Tokina ends at f/6.7. When they start combining longer focal range, the aperture usually starts suffering. So watch for the maximum aperture if you decide to get a superzoom. And the dimmer image due to the small aperture may lead to the AF hunting for focus.

Convenience

No doubt about it. Superzooms win hands-down. They offer the ultimate in convenience. Just pack one in your bag, and you're ready for almost anything. In fact, superzooms are my choice for travel photography. Remember, the more gear you carry on, the less energy and mood you have for photography. Be prepared to bring along faster films though.

Should you get 2 lens, or just one?

My advice is to avoid superzooms if you can. The only advantage of superzooms is convenience of having a wide focal range in one lens. This makes it very convenient for travel.

Savings ? Not really. Superzooms may seem cheap for the focal length it covers. But check again. A combination of 28-70 and 70-210 lens does not cost much more than a 28-200 lens. It may even cost less !! And the two lens have smaller filter diameters, which means you actually save on filter costs, not to mention that you actually have two physical lenses as a security. If one lens goes, you still have another (touch wood !!).

Having 2 lenses and changing them isn't as difficult as you think. And they won't weigh much more than one superzoom. Advertisements entice novice users with the wide-focal range, but they often play down the huge filter diameter, slower focusing speed and aperture. So unless you cannot do without the convenience of having all focal-length in one lens, you'd be better off hedging your bets on a 28-70 mm and a 70-210 mm.

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