Lens Basics: Mid-Range Zoom

Muddy Creek Falls
Canon EF 17-85mm

As we discussed in my previous post, the most important lens in your arsenal as you develop your photographic interests will be the mid-range zoom lens.  If you're using an APS-C sized sensor DSLR, this will be a zoom that begins around 15-18mm on the wide end and ends at the 55-135mm range on the telephoto end.  If you're using a full frame camera, the range will begin in around 24-28mm on the wide end and 135-200mm on the telephoto end.

I recommend buying the best lens you can afford without going crazy.  Professional lenses are great, but you can get by with less, and good photographic practices can often cover up some weaknesses in lenses.  For instance, if you know your lens is not sharp at its widest angle shooting at its widest aperture, you can often "fix" this by stopping down.  So if your widest aperture is f/3.5 at 17mm, try shooting at f/4 or f/5.6, or back up and zoom in a little.  Some lens weaknesses can also be corrected with software.  Barrel distortion is a common problem with consumer grade lenses at wide angles, and it can cause straight lines to look curved.  But this can also be improved or even removed in Lightroom and other software.  Buy the best lens you can afford, learn its weaknesses, and learn how to compensate for them.

Near St. Augustine Lighthouse
Canon EF 17-85mm

Most good lenses will be sharp and work just fine throughout most of their range.  Problems usually surface near either the shortest focal length or longest focal length.  At wider angles, lenses often loose sharpness around the edges and exhibit increased distortion.  Vignetting can also be a problem, where images get darker around the edges, especially the corners.  At the longest focal lengths, lenses also tend to lose sharpness.  Good reviews of lenses will let you know exactly what to expect from your lens before you buy.

Also, keep in mind that lens weaknesses may not even be noticeable in some types of photography.  Barrel distortion is a real problem when shooting architecture. But for flowers, you don't have straight lines, so you won't notice the problem as much.  And when it is a problem, distortion and vignetting can be improved or corrected with software.  It adds a little more time to your workflow, but at least you can deal with it.  Buying professional lenses can help with this tremendously, but you don't have to have professional lenses to get good pictures.

Baltimore's Inner Harbor
Canon EF 17-85mm

Here are some examples of mid-range zooms by Canon with prices you can expect at the time of this post.  Obviously, Nikon will have a similar lineup:

Professionsal
EF 24-70mm f/2.8L USM ($1400)

EF 24-105mm f/4L IS USM ($1100)

These lenses will not compromise on distortion, vignetting and sharpness, but as you can see, you're going to pay for it as well. The 24-70mm lens is more expensive because it is "faster"--it has a larger maximum aperture of f/2.8 instead of f/4.

Consumer
EF-S 17-55mm f/2.8 ($1060)

EF-S 15-85mm f/3.5-5.6 IS USM Lens ($700)

EF-S 18-200mm f/3.5-5.6 IS Lens ($600)

EF-S 17-85mm f/4-5.6 IS USM ($520)

EF 28-135mm f/3.5-5.6 IS USM ($450)

Of these, the 17-55mm and 15-85mm lens are the clear winners in terms of image quality.  The other three have comparable image quality with differences in price largely do to the focal lengths they offer.  I have used the 17-85mm lens extensively, though not the other two, and I can say that this lens has served me very well, and I have no real complaints about it.  It has significant weaknesses around 17mm (distortion, loss of sharpness, etc), but I've been able to handle it pretty well.  And I recently bought Canon's 10-22mm lens, so I no longer use 17-85mm lens at its extreme wide angle.

Canon's EF-S 17-55mm f/2.8 will be attractive to those who want a zoom lens with the ability to shoot at wide apertures.  Personally, though, the zoom range is so limited that I would often want to be closer to my subject. If you want a wide aperture and a longer zoom range, you could buy Canon's EF-S 15-85mm lens and Canon's EF 50mm f/1.4 ($350) for about the same price.  This way you get a more manageable zoom and the option to shoot at an even wider aperture than the zoom lens will give you. The choice is yours, of course, but you options.

Baltimore's Inner Harbor
Canon EF 17-85mm

Canon and Nikon both make "kit" lenses in the 18-55mm zoom range.  Generally these are not very well-built or sharp, and likely your camera will take better pictures with a better lens. If the lenses I listed above are all too expensive, consider older non-IS lenses that are still good quality.  I used to use Canon's  EF 28-105mm f/3.5-4.5 II USM, and I was very happy with it.  You may find one used under $200.  Be creative to find cheaper prices if you need to, but try to get yourself a lens that will let you exploit the benefits of the DSLR camera you own.