Remember the last time you went to the eye doctor? They told you to look at the chart and read the letters from 20 feet away. This is the most basic of eye exams however, it is very effective. So what does this have to do with photography? Well the answer is really quite simple, just as our eyes are important to our vision, a camera's lens is equally important to the final images produced by your camera.
Most of us will by a new camera based on the camera's features. The fact of the matter is, you should be looking at the lens. I tell my students all the time, in photography "Glass is God" meaning that if you have poor glass on your camera, you will likely have poor images as a result.
Most camera manufacturers know this and will create "packages or camera kits" with lower quality lenses to help sway potential customers with lower prices. I mean after all, if a Canon lens carries a list price of $1000, and for the same money you can buy a camera body, 2 lenses and get a great bag too, you'll be going for what's behind door no# 2. I am not suggesting that all so called "package" deals are bad, I am simply stating that if you truly want to turn out the best images, you should consider going Ala Carte.
See today's camera's are changing much like the computers of the 1980's and 90's. There was a faster machine to be had every 18 months of so. In this case it's the camera bodies, more specifically their insides, that are making this same sort of transition. About every 18 months or so a "new improved" version of what you just bought, is out on the market. It might be smaller, lighter and even cost less than the one you have, it might even have like twice the mega pixel rating. The one thing in this scenario that hasn't changed is the fact that you still have the same low quality lenses from the old system to put on this new race horse. Why? Because you bought the Kit and you don't want to totally replace your system.
Let's look at this a little deeper. A camera body is basically a black box. That's all that camera's have ever been. Sure they might be packaged with shiny knobs and dials and a glowing 2 in" screen for viewing your images, but understand without that lens, they are nothing but a black box. The quality of that lens will totally determine the quality of your final image. Period.
Now some might argue that you can Photoshop your images, or run a fractal sharpening program to bring out detail missed by the lens etc... yada yada yada. Without an initially strong image, you are only adding icing to a crooked cake. In stead of people asking what kind of camera do you have, they need to start asking what kind of lens do you have.
Different manufacturers have different ways of indicating that a lens is of better quality and has more functionality than others lenses they produce. For Nikon lenses are of the "G" Type and for Canon they are of the "L" type. These lenses typically have more functionality with your camera than other types of lenses, as well as a higher quality of glass.
So what does all this mean? Basically when you go to that optician to have your eyes checked if you need glasses, you can see better when the new prescription arrives. If you think of higher end lenses like a great set of glasses you are on the right track. Higher end lenses will produce a crisper cleaner image than those lenses produced to a lower quality standard. The lower quality standard lenses may be fine for general use however, if you need to "stretch" the lenses capabilities you will find that it doesn't perform as well.
Some simple tests you can do right at home using regular household items may help you determine just how well your lens performs. First off look at your lens, does it look clean? If your lens is removable, actually take it off of the camera and look through it. If you can actuate the aperture mechanism inside the lens, open it up completely, so you can see inside the entire lens. Hold the lens up to the light and make sure there isn't anything inside the lens like algae, dirt, bubbles or scratches on the elements that would degrade the quality of your images.
Now you will want to check for fall off in your lens. This is a darkening of the image as it reaches the edge of the frame also known as vignetting. It isn't a bad thing for portraiture, but for some other applications it might not be that desirable especially if it is heavy. To test this, simply place a 8.5x11 piece of white paper on an evenly lit, darker toned wall. You will fill the frame with the white paper, don't leave any edges showing. If you have a zoom lens you do 3 tests, first set the lens at it's widest setting, then at it's mid and finally at it's longest setting. You will have to move away as you shoot each consecutive image, each time filling the frame. It would be best to use a tripod for this test to insure angle and height remain the same, also to steady the camera. ( example; 1st shot will be done at 28mm, the second at 50 and the final at 75 mm. For a 28 to 70 mm zoom lens.)
The next test will be a pin cushion / barrel distortion test. This is a common problem with zoom lenses. When a lens reaches it's outer most settings, a straight line near the edges of the frame may bow out or contract inward. You can test this using a standard playing card. Evenly light the card, get in as close as you can and still be in good sharp focus, photograph the card. If you can't get close enough, use that same piece of paper from the last test and this time shoot it so the edges are showing. As you get in close, you will likely see the straight edges of the subject bow in or out as you zoom in and out. If these changes are drastic you might want to consider moving up in lens quality. You can access Canon or Nikon's website ( as well as other manufacturers) to get lens data.
The lens data you will likely see will vary depending on the manufacturer. Each of them have their own "alphabet soup" to describe their lens' functions and abilities. They also have a legend that goes along with this alphabet soup to help you determine which lens is best for you. The long and short of it is this. A lens with a lower minimum aperture or "F number" will likely cost you more and will also likely be a lens of higher quality. Lenses that offer vibration reduction or image stabilization are a good alternative to the lower F number lenses. While these lenses have a higher minimum F-number, they usually cost less and allow you to still shoot in low light situations. This is done by compensating the for higher minimum aperture with your shutter speeds. These lenses are designed to allow you to achieve a sharp photo at longer exposures because of their ability to reduce camera shake and lens motion. Finally you will want to make sure that you are purchasing a lens designed for digital use. Most of these will have some sort of "D" rating. Because your focus is so much more critical using digital than it was with film, a digitally rated lens is a must have.- Aloha
