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The 70-200mm type lenses being manufactured today are quite
good, sometimes great, and this goes for the lenses from many
of the top manufacturers...Nikon, Canon, Pentax, Minolta, etc.
However, using this type of lens requires a different mentality
compared to using shorter lenses like the 85mm, 50mm, or short
zoom (i.e., 28-105mm) type lenses.
Since you'll always be shooting in the telephoto range
with a 70-200mm type lens, your shutter speeds need to be higher
in order to get crisp results, especially if you need enlargements
to look tack sharp. At the long end of the zoom, handheld, be
sure to try for a shutter speed of at least 1/250th sec. Personally,
at the 200mm end of the zoom, I'm comfortable only when I'm getting
speeds of 1/500 and 1/1000th sec (and above). At these speeds
you can handhold and be reasonable sure (as long as you are somewhat
steady) that you will freeze both camera shake and subject movement.
Remember, at long telephoto lengths, camera shake is increased
significantly.
Another area to attend to with long focal length (zooms) is achieving adequate depth of field. You can get some really beautiful blurred background effects by using a zoom at its long end, with a shallow aperture like f4 or f5.6. But, beware of the extremely precise focusing necessary. The DOF using, for example, a 200mm at f4 is much more shallow than the DOF of an 85mm at f4, all other variables being constant. (See the link to our DOF chart on the main site.)
One quick note: For optimum sharpness and image quality with zooms, use an aperture that is at least 1 or 2 stops closed from its maximum aperture, especially if you own one of the inexpensive zooms. However, they do perform adequately at max aperture if you will not be enlarging the image to extra large sizes. Try f5.6 for starters when photographing at the long end (200mm) of the zoom. The expensive wide-aperture lenses perform quite well at f2.8, so stopping down is not as necessary.
The reason I'm pointing out these issues is because I too have
to force the longer lens mentality on myself when I use my Nikkor
80-20mm f2.8 lens. As with everything else, once you practice
and use these lenses during photo sessions, the necessary long
lens mentality will become second nature.
The longer zooms are very fun to use -- just make sure you exercise
adequate long lens technique!
--Eddie Bonfigli. |